摘要:

JANUARY 1939 THE ANALYST Vol. 64 No. 754 PROCEEDINGS OF THE SOCIETY OF PUBLIC ANALYSTS AND OTHER ANALYTICAL CHEMISTS AN Ordinary Meeting of the Society was held at the Chemical Society’s Rooms, Burlington House December 7th 1938 the President Professor W. 11. Roberts, in the chair. Certificates were read in favour of G. Carter B.Sc. A.I.C.; 0. B. Darbishire, BSc. A.R.C.S. D.I.C. A.I.C.; F. M. Dyke B.Sc. F.I.C.; ,4. A . Eldridge B.Sc., F.I.C. ; Prof. F. Feigl Dr. Ing.; G. H. Fraser ; M. B. Ichayoria M.Sc. Ph.D. A.I.C. ; R. Porter; A. C. Ratcliff B.Sc. ; W. H. Templeton B.Sc. F.I.C. The following were elected members of the Society :-W. A. ,ilexander B.Sc., A.I.C.; D. R. A. Davies B.Sc.; E. R. Jones B.Sc. Ph.D. F.I.C. M.D. Ch.B., D.P.H.; H. A. Jones A.I.C.; Dr. B.A. Macola; J. M. Malcolm A.I.C.; Mrs. S. M. L. Tritton M.P.S. F.I.C.; S. A. Ullah B.Sc. Ph.D. A.I.C. The following papers were presented and discussed :-“The Selective Oxidation of Animal and Vegetable Fats A New Constant,” by W. A. Alexander B.Sc., A.I.C. ; “The Determination of the Essential Oils of White and Brown Mustards,” by R. C. Terry M.Sc. A.I.C. and J. W. Corran Ph.D. F.I.C. ; “The Electrolytic Determination of Bismuth,” by F. G. Kny-Jones M.Sc. NORTH OF ENGLAND SECTION A MEETING of the Section was held in Manchester on October Znd 1938. The Chairman (Prof. T. P. Hilditch) presided over an attendance of thirty-seven, which included the President (Professor W. H. Roberts) who introduced a discussion on the Food and Drugs Act 1938 in which many members took part.The following communications were made and discussed :-“L4 Note on Nigerian Ginger,” by P. H. Jones F.I.C. and a paper on the “Quantitative Determination of Mercury in its Compounds with Special Reference to the Assay of Solution of Mercuric and Arsenious Iodide,” by H. Brindle B.Sc. F.I.C. Ph.D. and C. E. Waterhouse A.I.C. Ph.D. A Meeting of the Section was held in Manchester on December loth 1938. The Chairman (Prof. T. P. Hilditch) presided over an attendance of thirty-nine. The following papers were read and discussed :-“The Estimation of Vitamins and Hormones,” by R. A. Morton Ph.D. D.Sc. F.I.C.; ‘‘A Note on the Behaviour 2 EVANS A NEW COLOUR REAGENT FOR LEAD AND ITS USE of Rice Bran,” by C. Louden BSc. F.I.C. and F. L. Kinsella; “A Convenient Method of Estimating the Hydrocyanic Acid generated by Linseed Cake,” by C.Louden B.Sc. F.I.C. and H. Antrobus. Resolutions were passed congratulating Mr. U. A. Coates on the occasion of the diamond jubilee of his wedding day and Mr. H. Humphreys Jones on his appointment as a Justice of the Peace. SCOTTISH SECTION A 4 ~ Ordinary Meeting of the Section was held in the Central Station Hotel Glasgow, on November 18th 1938. The meeting was of an informal nature and the following subjects were discussed:-“American Food and Drugs Act,” introduced by R. G. Thin; “Copper Content of Tomato Purke,” introduced by A. Dargie; “Memorandum on the Food and Drugs Act 1938,” introduced by M. J. Robb; “Determination of Alumina in Water,” introduced by R. T. Thomson; “Determination of Lactose and Sucrose in Milk Chocolate,’’ introduced by H. C. Moir ; “Air Raid Precautions,” introduced by J. W. Hawley

ISSN:0003-2654    

DOI:10.1039/AN9396400001

出版商:RSC    

年代:1939

数据来源: RSC

摘要:

2 EVANS A NEW COLOUR REAGENT FOR LEAD AND ITS USE A new Colour Reagent for Lead and its Use as an Indicator in the Titration of various Cations and Anions* (Read at the Meeting October 5 1938) COLOUR reactions for lead due to the formation of soluble compounds with the range of stability necessary for indicator purposes are rare.ll The well-known colour formed with diphenyl thiocarbazoneltg is intense and easily produced but it is so stable as to preclude its use as an indicator. Carbazones give relatively intense colours with many metals including lead c ~ p p e r ~ iron nickel cobalt zinc, thallium* and others but here again the lead colour is so stable that it is not readily destroyed by most precipitants. It was observed that if an acetone solution of diphenyl carbazide is added to a solution of lead nitrate containing pyridine nitrate a very pale pink colour is produced; if the solution is allowed to stand the colour slowly deepens becoming eventually (after about 20 hours) a dark red proportional in depth to the amount of lead present.After a considerable amount of work a reagent was evolved which immediately developed the full colour. REAGENT.-The reagent used in the work done for this paper was prepared as follows: Solutiom required-(a) A 1.5 per cent. solution of diphenylcarbazide in alcohol (this solution seems to keep its properties indefinitely although it darkens and * Communication from the Research Department Woolwich AS AN INDICATOR IN THE TITRATION OF VARIOUS CATIONS AND ANIONS 3 the carbazide is probably converted into carbazone); (b) purified pyridine (vi& infra); (c) dilute nitric acid (sp.gr.1.2). A mixture of 10 ml. of (a) with 30 ml. of (b) was diluted with 120 ml. of cold water 2 ml. (carefully measured) of ( c ) were added and the liquid was heated to boiling and allowed to stand on the bench overnight after which it was ready for use. It has subsequently been found that the heating is entirely unnecessary, and it has consequently been discontinued; the reagent is now prepared as follows: Preparation.-A mixture of (b) (c) and water in the correct proportions is made up in bulk and to the required volume of this mixture an amount of (a) is added to produce the strength indicated above. The liquid is allowed to stand overnight and is then ready for use.With a fairly new (a) solution the colour directly after mixing will probably be very pale; if a test is made with it on a lead nitrate solution the colour produced is almost imperceptible at first but gradually deepens to the full shade if allowed to stand for some hours. After the reagent has stood for its appointed time its colour is a fairly deep orange-brown and on being mixed with lead nitrate solution it should develop its full colour (a cherry-red with 1.0 mg. of lead nitrate in 100 ml. of water) immediately. The reagent keeps fairly well for several days but it slowly deteriorates and eventually ceases to give any red colour whatever with lead. Since the completion of the work for this paper however I have found that an alcoholic solution of diphenyl carbazide which has been made up for several weeks (in one instance five) produces a reagent which can be used without any standing (presumably because the carbazide has been oxidked to carbazone).If only fresh carbazide solution is available the lead and zinc colours can be developed by the cautious addition drop by drop, of bromine water to the liquid after the addition of the reagent (for lead until the full colour is produced ; for zinc 5 drops). A satisfactory reagent seems also to be produced by warming 2 ml. of the carbazide solution with 1 drop of hydrogen peroxide (20 vols; stabilised with sulphuric ?zot with phosphoric acid) until the brown colour ceases to deepen and then mixing with 30ml. of the pyridine-nitric acid-water mixture. These oxidising agents however are very liable to destroy the properties of the reagent altogether if used in slight excess and on the whole it is better to prepare the reagent by the method given above.THE TEST.-If a small amount of lead nitrate solution is neutralised and diluted to about 100ml. and 10ml. of the reagent are added the red colour developed is proportional to the amount of lead present ; with 0.002 g. of lead nitrate the colour should be a fairly dark cherry-red; a blank test done in the same way, but without lead gives a pale orange-brown due to the colour of the reagent. The colour difference is made more apparent by adding acetone which seems to eliminate the reddish factor from the reagent colour without disturbing that due to the lead; the colours are now a permanganate tint and a very pale yellow, respectively.If to the solution containing the developed lead colour successive additions of very dilute nitric acid are made it first turns paler and then at a certain point is entirely bleached; if instead of nitric acid dilute ammonia is added the colour first darkens and then at a certain point is replaced by the orange-brown shade characteristic of alkaline solutions of diphenylcarbazide. There is thus a pH range over which the colour is effective and a fairly limited on 4 EVANS A NEW COLOUR REAGENT FOR LEAD AND ITS USE at which it is a t an optimum; this is the reason why the 2 ml. of nitric acid added to the reagent must be carefully measured and why the lead solution has to be neutralised before making the test. The colour seems to be destroyed by anything liable to precipitate lead under the pH conditions prevailing; thus phosphates, arsenates tungstates vanadates molybdates and citrates destroy it promptly and sulphate in any appreciable amount weakens it.It is this fact that makes the colour reaction interesting because so many other metals give a similar colour (vide i9tfYa) that it is not of much use as a test for lead; but if the colour can be progressively removed by addition of small amounts of any of the reagents mentioned above (i.e. by titration) it can obviously be made the basis of a volumetric process for minute amounts of lead; on the other hand it should equally be possible to use it as an indicator in the titration of these reagents with lead nitrate solution.The following method has been worked out for the volumetric determination of lead: VOLUMETRIC PROCESS FOR LEAD.-The solution of lead as nitrate neutralised (to litmus paper) with ammonia is placed in a flask and diluted to 100 ml.; 100 ml. of distilled water are placed in a similar flask; 10 ml. of reagent are added to each, followed by 30ml. of acetone. The titrating liquid is prepared in the following manner:-Ten ml. of syrupy phosphoric acid are made up to 100 ml. (A) ; 20 ml. of (A) are made up to 250 ml. (B) ; 10 ml. of (B) are diluted boiled cooled and made up to 1000 ml. (C). The lead colour is titrated away with solution (C> until the colours of the supernatant liquids in the two flasks match. The colour at first diminishes rapidly but towards the end-point the change becomes slower; there is no difficulty with the titration up to within about 0.4 ml.of the end-point; from then onwards the colour change is very slight and gradual; the presence of the slightly brownish precipitate of lead phosphate somewhat complicates the matching and when matching becomes difficult it is desirable to allow the liquid to stand for a minute or two after each addition. The end-point however can be determined with reasonable speed and certainty. The titration can be performed as accurately in the absence of acetone but it then becomes much slower as towards the end, the precipitate has to be left to settle for a considerable time after each addition; an additional function of the acetone is to prevent adsorption of the colour on the precipitate making the latter a mauve colour and so masking the end-point.The phosphoric acid standard must be standardised against lead nitrate. The method was tested with the following results : (a) With Acetone. Lead nitrate taken g* 0-0090 0*0080 0.0070 0.0060 0*0050 0.0040 0-0030 0*0020 0*0010 0*0100 T i t r a t i o n ml. 16-10 14-40 12.30 10.70 8.85 7.00 5.20 3.65 1 *75 17.75 Lead nitrate found g. 0.00907 0*00812 0.00694 0.00603 0-00499 0.00395 0.00293 0.00206 0.00099 0~0100 AS AX INDICATOR I N THE TITRATION OF VARIOUS CATIONS AKD ANIOKS 5 The first nine of these results were calculated from the factor (1.0 ml. = 0.0005645 g. of Pb[NO,],) obtained by the tenth titration; the tenth result was calculated from the mean of the factors obtained from the other nine (1.0 ml.= 0*0005640 g. of Pb[NO,],). (b) Withowt Acetone. Lead nitrate taken g. 0~0100 0*0090 0.0080 0.0070 0.0060 0.0050 0.0040 0.0030 0~0020 0~0010 Titration ml. 9-15 8.10 7.30 6.35 5.45 4.55 3.65 2.70 1 -80 0.95 Lead nitrate found g. 0.0 1006 0.0089 1 0.00802 0.00698 0.00600 0.00500 0.00401 0.00297 0.001 98 0 a 0 0 104 For these determinations a stronger phosphoric acid solution was used whose factor was 1.0 ml. = 0.00110 g. of Pb(NO,),. The precipitate formed in the course of titration appears to have the com-position PbO(Pb,[PO,],),. Titration with Ammonium Vanadate.-Lead can be titrated in the same manner with ammonium vanadate.The following results were obtained by the use of a solution containing 0.0184 g. of NH,V032H,0 in 1000 ml. (1.0 ml. = 0*00008 g. of V). Lead nitrate taken g* 0~0100 0*0090 0.0080 0*0070 0.0060 0*0050 0.0040 0*0030 0.0020 0.0010 Titration rnl. 13-80 12-45 11.05 9-70 8-32 7 -00 5.55 4.20 2.80 1.37 Lead nitrate found R. 0.00998 0~00900 0.00799 0-00701 0.00601 0.00506 0.00401 0.00304 0.00202 0-00099 The factor (1 ml. = 0*000723 g. of Pb[NO,],) was calculated from the mean of the first four results. The titration is somewhat sharper than with phosphate, but the composition of the precipitate does not appear to correspond with any simple relationship of Pb:V. Probably a mixture of meta- and ortho-vanadate is formed (cf.Calliere and Guiter’s work).15 DETERMINATION OF ACID RADICLES.-M~~Y acid radicles are precipitated by lead salts at or near the neutrality point. The difficulty in using these reactions volumetrically apart from the lack of an internal indicator is the tendency of lead to form basic salts thus rendering the composition of the precipitate un-certain. The reagent proposed besides being a good internal indicator provides a very efficient buffer thus keeping the pH value within narrow limits; consequentl 6 EVAKS A NEW COLOUK KEAGEXT FOR LEAD AND ITS USE several volumetric processes of very fair accuracy have been evolved. The acids dealt with are the following :-molybdic tungstic vanadic phosphoric and arsenic. None of these acids with the exception of vanadic gives any marked colour with the reagent (molybdic acid gives a pale orange) ; consequently if a solution of lead nitrate is run into a solution of one of their salts containing the reagent no marked colour change takes place until the lead is in excess when the liquid begins to turn red.The end-point is very similar to that of a titration with alkali using phenolphthalein as indicator. Molybdates.-The solution is neutralised with ammonia or nitric acid as the case may be (it is desirable that it should be on the alkaline rather than the acid side) and diluted to 100 ml.; 10 ml. of the reagent and 30 ml. of alcohol are added. The mixture is titrated with lead nitrate solution (1 g. of Pb[NO,] made up to 1000 ml.) to the appearance of the first permanent pink flush.The lead solution should be standardised in the same way against ammonium molybdate. Tested in this manner on a solution of ammonium molybdate the method gave the following figures : Molybdenum Titration (calc. froiii taken Titration the 0.004 Mo. figure) g. ml. mI. 0~0100 36.00 36-10 0.0050 18.05 18.06 0.0040 14.45 -0.0030 10.80 10.84 0~0020 7.25 7.23 The titration results therefore are strictly proportional within the limits of experimental error; they are not quite comparable with those next to be cited, as an old lead nitrate solution probably slightly concentrated was used. The process was tried on a sample of MOO obtained in the course of a molyb-denum determination. The sample which weighed 0.0527 g. (this included the weight of the filter-ash) was dissolved in sodium hydroxide and made up to 250 ml.; portions were neutralised separately with nitric acid and titrated as described above. Volume taken ml. 25.0 25.0 50.0 20.0 10.0 10.0 10.0 10.0 10.0 ‘litration ml. 12.30 12-30 24.70 9-80 5-00 4.90 4-95 4.95 4.95 MOO, g. 0.0051 9 0-00519 0-01042 0.004 14 0.002 1 1 0-00207 0.00209 0~00209 0.00209 -_- Calculated total weight of MOO, P -0.06 19 0.0519 0-0521 0-0518 0.0527 0.05 18 0.0522 0.0622 0.0552 * Neutralisation rather too much on acid side. j- Faintly alkaline AS AN IKDICATOR I N THE TITRATION OF VARIOUS CATIONS AND ANIONS 7 It will be noted that leaving out of consideration (e) the neutralisation of which was at fault the results group themselves closely round their mean 0.0520; the excess 0.0007 g.is presumed to be the weight of the filter ash contained in the sample. Details of the standardisation are as follows : Molybdenum Titration (calc. to taken Titration 0.010 g . of Mo) Xean g . ml. ml. ml. 0*0050 17.8 0.0030 10.7 35.7 0.0020 7.1 35-5 0.0040 14.2 35*6} 35.5 35,575 Hence 1.0 ml. E 0*0004218 g. of MOO,. From the foregoing figures it appears that the reaction is not quite stoichio-metric for the formula PbMoO, 1 atom of Pb = 1.03 instead of 1.00 atom of Mo. Phos$hates.-The following titrations were carried out on the phosphoric acid solution used for titrating lead (vide sz@ra). In view of the very faint acidity of the solution no neutralisation was attempted.The titration was performed in exactly the same manner as for molybdates escept that 30ml. of acetone were used instead of 30 ml. of alcohol. H,PO P205 found calc. P,O present, solution Titration from formula calc. from hTaOH taken Pb(NO3)2 PbO (Pb3 [Po41 z 3 filtration ml. 11-11. g . b", 10.0 6.9 0-000888 0-000898 5.0 3.6 0.000460 0.000449 4.0 2-8 0*000360 0.000359 3.0 2.2 0.000283 0~0002$4 2.0 1-5 0~000193 0.0001 80 1.0 0.T 0~000090 0*000090 It will be noted that the coinpound formed when lead nitrate is run into excess of phosphoric acid appears to be PbO(Pb,[PO,],) instead of the PbO(Pb,[PO,],) formed when the phosphoric acid is run into excess of lead. Arsenates.-The following titrations were carried out exactly as for phosphates; the solutions titrated were very slightly on the alkaline side of neutrality.AS' taken s. 0.00 100 0.00080 0-00060 0.00050 0*00040 0.00030 0*00020 0.000 10 Titration ml. 7 *5 6.0 4-45 3.8 3.0 2-3 1-45 0-75 Calc. factor 0.001 A s v = I3b(NO3j2 g. 0.0075 0.007 5 0.0073 0.0076 0.0075 0.0077 0.0075 0.0075 Asv f 0 u nd , calc. from mean factor s". 0~001000 0~000800 0-000600 0.000506 0.000400 0-000308 0~000200 o*ooo 100 Mean 0.007 8 EVANS A NEW COLOUR REAGENT FOR LEAD AND ITS USE The atomic ratio As":Pb calculated from the mean factor is 1:1.70 which lies about half-way between the two ratios given for phosphates (4:7 and 6:10 vide supra). Vanadah.-The acids so far dealt with give little or no colour with the reagent; with vanadium this is not so.Vanadium" gives a colour almost identical with that of lead V'" gives a very intense violet; in a titration with lead V'" does not come into consideration but it will obviously be necessary to ensure that all vanadium is in the highest stage of oxidation. If a neutral solution of a vanadate to which the reagent has been added is titrated with lead nitrate solution the cherry-red coloui- of the V" fades as lead vanadate is precipitated till only the colour of the reagent itself is left; an excess of lead then causes the lead colour to appear. The titration is therefore very easy to perform; it is carried out in exactly the same way as that for phosphates (Le. neutral solution volume 100 ml.10 ml. of reagent and 30 ml. of acetone). A series of titrations carried out on ammonium vanadate gave the following results : Arsenites do not appear t o influence the titration. Vanadiuniv found Factor calc. 7-- 7 from result Calc. from Calc. from Vanadiumv 0.001 V = ml. mean of factors formula taken Titration Pb (NO,) 0*0008 - 0.00056 3PbO[Pb(VO,)J, g* ml. 0*00160 0*00120 0~00080 0.00072 0.00064 0.00056 0.00048 0-00040 0.00032 0.00024 0*00016 0*00008 12.40 9.40 6.40 5.80 5.15 4.50 3.90 3.20 2.60 1 -95 1 -25 0-65 7.75 7.84 8-05 8.04 8.12 8.00 8-12 8.12 7.81 8-12 0.001544 0.001 17 1 0.0007 97 0.000722 0.00064 1 0.000560 0.000485 0.000398 0.000324 0-000243 0*000156 0.00008 1 0.001 527 0.001 158 0.000788 0.0007 14 0.000634 0.000554 0.000480 0.000394 0.000320 0-000240 0.000154 0*000080 It will be noted that results above 0.001 g.tend to be low although those below that amount show very good agreement; for this reason the method is not recommended for amounts of vanadium in excess of 0.001 g. Hence the factor from which the results in column 4 were calculated was the mean of the first four within the accepted range (those enclosed in brackets); this factor is 1.0 ml. G 0.0001245 g. of V; from this the atomic ratio of V Pb in the precipitate can be deduced giving 1 :1*236 roughly corresponding to 3(PbO) (Pb[V03]2)2 which requires an atomic ratio of 1:1*25 and gives a factor of 1 ml. = 0.0001232 or possibly a mixture of meta- and ortho-vanadate is formed (vide supra).A paper has recently been published (ANALYST 1938 63 870) in which is described a volumetric method for determining amounts of vanadium from 0-01 to 0.001 g., covering the interval between this method and the ordinary permanganate process. The whole range of amounts of vanadium down to below 0.08 mg. can therefor AS A?! INDICATOR IF THE TITRhTION O F VARIOUS CXTIOKS AND ANIOX'S 9 now be determined volumetrically. When it is remembered that 0.2 mg. of vanadiuri gives only a very faint and 0.1 mg. an almost imperceptible colour with hydrogen peroxide in the ordinary colorimetric process5 the significance of the process just described becomes apparent. Tzt@ates.-The last member of the series of acids under consideration is exceedingly difficult to determine in small amounts.We are not here concerned with its separation from other elements (cf. Schoeller,6 Yagoda and Fales,' HalberstadP) ; the present research was undertaken primarily to provide the necessary step of an accurate means of determining the small amount when separated. Lead tungstate is precipitated very completely from neutral solution, but it readily dissolves in either acid or alkali; from pyridine-buffered solution, however precipitation appears to be as complete as one could wish. It seemed obvious that if the constitution of the precipitated lead tungstate could be regulated the method of titration already described for phosphates etc. should be available also for tungstates. The first experiments were made by adding a known excess of lead nitrate to the buffered solution and titrating the excess of lead away with phosphoric acid as described already.The results obtained were only approximate and tended to be high (i.e. they were not very consistent among themselves and an excess of lead over that required by the formula PbWO, was used up). Apparently basic compounds (or adsorption complexes) were being precipitated and these as might be expected with tungsten were of uncertain composition; it was felt that with this particular element an attempt must be made to produce a precipitate of the theoretical composition PbWO,. After many experiments it was found that the addition of boric acid seemed to prevent the adsorption of lead (basic compounds did not appear to be formed); in fact too much boric acid swung the results over slightly in the opposite direction.The following figures illustrate this effect: Boric acid added, Tungsten saturated taken solution s. ml. Titration, standard in1 . Pb(NOA2 Tungsten found, calc. from formula PbWO4 g. 0.003 0.003 0.003 0.003 0.003 nil 20.00 - 13.95 =6*05 0.00336 10 10*00- 4.82 =~5*18 0.00288 10 11-00- 5*80=5*20 0.00289 5 10.00 - 4.82 =5.18 0.00288 2 10.00 - 4-65 -5.35 0.00297 A series of titrations was accordingly made in which 2 ml. of saturated boric acid solution were added to the neutralised tungstate solution diluted to such a volume that with the lead nitrate solution to be added the volume would be about 100ml. the excess of standard lead nitrate was next run in followed by 10 ml.of the reagent and 30 ml. of acetone; the excess of lead was then titrated with standard phosphoric acid exactly as described at the beginning of this paper. The following figures were obtained 10 EVANS A NEW COLOUR REAGENT FOR LEAD AND ITS USE Titration, -7 A r Pb( NO,) Pb (NO,) 2 Tungsten solution Tungsten solution equix to required from PbWO, taken H3PO4 added H,E-'O for WO, formula solution found calc. PWO,), g. nil. ml. 1111. nil. g. 0~0100 0.0090 0*0080 0-0070 0*0060 0.0050 0*0040 0-0030 0*0020 0-0010 2.40 4.15 1-00 2.80 4.70 6.60 3.15 5.25 1 46 3.65 20.00 20.00 15.00 15.00 15.00 15.00 10.00 10*00 5-00 5.00 2-12 3.67 043s 2-48 4.16 5.85 2.79 4-65 1.28 3-23 17-88 16-33 14.12 12-52 10.84 9.15 7.21 5.35 3.72 1.77 0.00994 0-00907 0.00785 0.00696 0.00602 0.00508 0.00401 0.00297 0~00207 0*00098 Standardisation 1 ml.of H,YO solution =- 0.885 ml. of Pb(NO,) solution. Repeated attempts to filter out the lead tungstate before titration invariably It would seem that lead is withdrawn as a loose adsorption Some titrations were also carried out on amounts of tungsten unknown to gave high results. complex which is broken down during the titration. the operator. The results were as follows: Titration, --h-- r \ (NO,) 2 Pb(NO,) Tungsten Pb (NO,) solu tiori solution found calc. Tung5ten solution equix t o required from PbW04 given H3~04 added HJ'O for WO formula g.ml. nil. 1111. in1 . g. 0.00370 15-05 20.00 - 13-32 = 6.68 0.0037 1 0-00610 10.50 20.00 - $).I% == 10.88 0.00604 0.005;50 11.40 20.00 - 10.09 = 9.91 0.00561 0-0008.5 21.10 20.00 - 18-67 = 1 a33 0.00074 0.00 122 20-20 20.00 - 17.90 = 2.10 0.001 17 0.001 88 19.00 20.00 - 16.80 = 3.20 0*00178 Standardisation 1 ml. of H,PO solution = 0.85 ml. of Pb(NO,) solution. The foregoing work was carried out before the direct titration process for phosphates etc. was discovered (vide supra); it seemed worth while therefore to ascertain if this process was also available for tungstates. The titration was performed in the manner described for vanadium but 40 inl. of acetone instead of 30 were added; as the end-point was rather difficult to observe 1 ml.of the lead nitrate standard was added to a blank and the tungsten solution was titrate AS AN INDICATOR IN THE TITRATION OF VAliIOUS CATIOSS AND ANIONS 11 until the colours matched 1 ml. being deducted from the result. results were obtained: The following Tungsten taken g. Titration solution ml . (Pb"P3J2) Tungsten found, cslc. from PbWO formula g. 0.0100 18.9 - 1.0 = 17.0 0-O099c? 0.0050 1O-0-1~0= 9.0 0-00500 0~0040 8*3-1.0= 7.3 0~00405 0-0030 6*4-1.0= 5.4 0.00300 0.0020 4.6-1.0= 3.6 0~00200 0-0010 2.9-1*0= 1.9 0*00106 0*0041 8.0-1.0= 7.0 0.0039 Unknown to operator Owing to the production of a slight mauve tint due presumably to ad-sorption of the lead colour on the precipitate it is as well to allow the vessel t o stand for a few minutes before the final matching.Somewhat contrary to expectation therefore tungstic acid alone amongst the acids dealt with appears to throw down the normal lead salt. The addition of acetone is more important in titrations of tungstates than of the other acids, as without it the lead colour is adsorbed on the lead tungstate making the end-point very difficult to observe. OTHER VOLUMETRIC METHODS FOR TUNGSTEK.-A paper published in 193611 contains an account of various diamine scarlets used as indicators for lead in a lead-tungstate titration somewhat similar to that given here. The dyes act as adsorption indicators and the results given are excellent but the quantities dealt with are not as small nor as varied as those which form the subject of this paper; also titration has to be carried out at the boiling-point.Another published volumetric method for tungsten appears to rely on some form of acidimetry.12 Dotreppe's reduction method13 has been severely criticised by H0lt.1~ NEUTRALISATION.-In view of the fact that carbonates seem to act in the same way as phosphates etc. in destroying the lead colour which is the subject of this paper it is necessary to bear in mind their possible introduction during neutralisation. For this reason it is best to boil the solution neutralised with sodium hydroxide and then make faintly acid with nitric acid and after cooling to bring it back to neutrality or faint alkalinity by cautious addition of dilute ammonia (mt sodium hydroxide solutionj. The exact pH value does not matter very much except where tungstates are being titrated as then the colour is being matched and the intensity of the colour is extremely sensitive to pH value.In this instance it is best to add 10 ml. of 20 per cent. ammonium nitrate solution to both the sample and the blank (the latter must not be omitted because ammonium nitrate distinctly lightens the colour) before adding the reagent. OTHER Acms.-The titration should theoretically work with chromates, but when this was tried a dark brown colour developed during the titration and The titration of tungstates is being investigated further 12 EVANS A NEW COLOUR REAGENT FOR LEAD AND ITS USE entirely obscured the end-point. Many organic acids (e.g. citric) are precipitated by lead in neutral solution and the titration should undoubtedly be available for them.In all the work hitherto described the strength of the titrating solution was 1.00 g. of lead nitrate per 1000 ml. It is desirable always to standardise it against the particular ion to be titrated and to use the same batch of reagent. colours with a number of ions; its behaviour is summarised in the following table: BEHAVIOUR OF THE REAGENT WITH DIFFERENT IoNs.-The reagent gives I O N CUII Crvl Cr'" Fe'" FeT1 HgII HgI Znil COI' Ni" Pb" CdII RE.4CTION ION RBACTIOS Red colour immediately fading and re-placed by the pyridine blue colour. No effect. No effect. Fe(OH) precipitated; no colour. Red colour. . Intense violet colour. Intense violet colour. Purple red colour tending to precipitate.Purple red colour tending to precipitate. Purple red colour tending to precipitate. Red colour. Red colour. Slight reddish brown (impurity ?). Red colour. Intense violet colour. No effect. No effect. Pale orange bronx . Slight yellow colour. Red colour. No effect. No effect. Slight brownish-red. Slight red colour (probably impurity) . C1' SO,'' NO,' PO,"' AsO4"' AsO3"' SO," No action. The red colour of vanadiumV is not interfered with by titanium" which gives no colour itself. Citrates and tartrates appear to destroy the colour not only of the lead complex but of that of vanadiumv and vanadiumiv as well. Many of the coloured compounds notably those of zinc nickel and cobalt are extractable with chloroform; that of lead seems to be partially and with difficulty extracted but slowly destroyed the reagent passing into the chloroform.The action of copper (vide su@z) appears to destroy the reagent as the solution no longer gives a red colour with lead; copper must therefore be eliminated. Sonre of the colours are probably merely those given with carbazones. It seemed worth while to attempt titrating away the colours of some of these cations in much the same way as was done for lead. Zinc and nickel were tried, but only with zinc was success achieved; the nickel complex seems to be too stable for its ready titration. ZINC.-TO obtain a satisfactory colour with this metal a rather higher PH is needed than for lead; consequently if one attempts to form it in the same manner as with lead the appearance of the colour is somewhat uncertain.Chloroform appears to catalyse the formation of the coloured compound which dissolves in i t ; this has the additional advantage of concentrating the colonr nnd making the titration sharper. The following process was tried :-The neutralised zinc solution was dilutcd to 100 ml. 30 ml. of acetone were added followed by 5 ml. of the reagent and lastly 5 ml. of chloroform ; it was shaken and then titrated with A 1 ,'lo00 paassiu AS AN INDICATOR IN THE TITRATION OF VARIOUS CATIONS AND ANIOXS 13 ferrocyanide solution with vigorous shaking after each addition until the chloroform showed only the colour of the reagent. Results thus obtained were: Zinc found calc. Titration from the 0.001 Zn Zinc taken (niIjl000 K,Fe[CN,) titration figure h”.ml. e;. 0*0010 8-30 O.OOO!)Yi (calc. from mean factor of the other results) 0.0005 4.10 0.000494 0.0004 3.35 0.000403 0-0003 2.50 0.00030 1 0*0002 1.70 0~000205 0~0001 0.85 0~000102 If the titration figures are calculated on the ordinary basis on the assumption that K,Zn,(Fe[CN],) is precipitated the results are about 20 per cent. too low. The ratio Zn K4Fe(CN) is approximately 2 atoms of Zn 1 molecule of K,Fe(CN),. Subsequent determinations have shown that if in the neutralisation, an excess of pyridine is added to the faintly acid solution the exact ratio is obtained and therefore the theoretical factor (1 ml. of M/1000 K,Fe(CN) = 0.0001308 Zn) for Zn,Fe(CX) can be used. The only modification required in the process described above is that neutralisation should be carried slightly to the acid side of neutrality and 1 ml.of 20 per cent. pyridine should then be added. It has since been found that minute traces of nickel are exceedingly liable to be introduced in the course of an analysis and that these entirely upset the titration by producing a pink colour which cannot be titrated away. This can be counteracted by adding 2 drops of 10 per cent. potassium cyanide solution immediately after the pyridine and allowing to stand for 2 or 3 minutes before adding the reagent. The titration should then be completed without delay as the nickel colour tends to recur. The blank liquid is treated in the same manner. PYRID1NE.-The question of the supply of pyridine for these experiments was one of some difficulty.Commercial pyridine is exceedingly impure and the reagent prepared from i t gave no colour a t all but a white precipitate with lead; other supplies of alleged “pure” pyridine gave a reagent which produced a lead colour that almost immediately faded. AnalaR grades of pyridine were not tried. Satisfactory samples were supplied by both Messrs. Hopkin tk Williams and British Drug Houses and doubtless the requirements could easily be met by any manufacturer who knew them. The interfering substances would seem to be ammonia or homologues or derivatives of pyridine ; water apparently has no effect whatever. It was found that if commercial pyridine is distilled from lead nitrate and the distillate subsequently boiled for 10 minutes in an open vessel the product can be used to prepare a very fair reagent; it however does not keep nearly as long and on the whole is not so satisfactory as that made from Messrs. Hopkin & Williams’ or the B.D.H. product. The use of other organi 14 SHENKAN QUINALDINIC ACID AS A REAGENT FOR COPPER ZISC ASD CADMIUM bases ( e g . cinchonine and aniline) is being investigated with fairly promising results up to the present. 1. 2. 3. 4. 6. d . 7. 8. 9. 10. 11. 12. 13. 14. 15. REFERENCES N. L. Allport and G. H. Skrimshire ANALYST 1932 57 440. C. Miller Cheinist Analyst 1930 25 90. 1. P. Krumholz and F. Honel Microchimica Arta 1937 2 177. B. S. Evans unpublished work. B. S. Evans and S. G. Clarke ANALYST 1928 53 480. Mi. R. Schoeller Analytical Cheinistry of Tantalitm and Niobiiiiii Chapman ei Hall 1937, H. Yagoda and H. A. Fales J Amer. Chewa. SOC. 1936 58 1493; 1938 60 610. S. Halberstadt Cow@. rend. 1937 205 987. H. Fischer Mikrochem. 1930 8 319. E. S. Vassermann and I. Suprunovitch J . Chim. Ukraine 1934 9 330. 2. Raichinstein and N. Korobow 2. anal. Chein. 1936 104 192. A. del Campo and F. Sierra Anal. Fis. Quirn. 1933,31 356. G. Dotreppe Chim. et Ind. Special Number 173 (March 1931). M. L. Holt I n d . Eng. Chena. Anal. Ed. 1934 6 476. E. Carrikre and H. Guiter Conapt. rend. 1937 204 1339. p. 80. RESEARCH DEPARTMENT Septembev 1938 WOOLWIC

ISSN:0003-2654    

DOI:10.1039/AN9396400002

出版商:RSC    

年代:1939

数据来源: RSC

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14 SHENKAN QUINALDINIC ACID AS A REAGENT FOR COPPER ZISC ASD C.IDMIUM Quinaldinic Acid as a Reagent for Copper, Zinc and Cadmium BY R. J. SHENNAN MSc. A.I.C. QUINALDINIC acid has been proposed as an analytical reagent for the quantitative determination of a number of and has been recommended as being suitable for the separation of copper from cadmium.l14. The following investi-gation was undertaken to establish the (PH range over which complete precipitation could be effected for the metals copper zinc and cadmium and so to define more precisely the conditions for determination. DETERMINATION OF CoPPm.-Copper sulphate AnalaR (15 g.) was dissolved in water and the solution was diluted to 2500ml. The copper-content of this solution was determined by the sodium anthranilate6 method (found copper, 0.03842 g.per 25 ml.). To 25 ml. of the standard copper solution were added 25 ml. of sodium acetate solution (5 g.) a measured quantity of glacial acetic acid and water to make up 150 ml. The solution was boiled and 20 ml. of reagent solution (5 g. of sodium quinaldinate in 250 ml. of water) were added slowly. After 45 minutes the pre-cipitate was collected on a No. 4 sintered glass crucible and the filtrate was reserved for subsequent pH determination by means of a hydrogen electrode. The pre-cipitate was washed well with water dried at 125' C. and weighed. The results are given in Table I. Attempts to extend the range above PH 7 resulted in the precipitation of copper hydroxide. In the absence of sodium acetate it was found possible to attain pH values below 2 and to extend the range of copper precipitation to $H 1.5.Complete precipitation was obtained over the pH range 2-5 to 6-96 SHENNAN QUINALDINIC ACID AS A REAGENT FOR COPPER ZINC AND CADMIUM 15 TABLE I Copper taken in each Experiment = 38-42 mg. Acetic acid 11. 125" loo* 40* 35" 100 75 50 5 0.05 nil 0.69 0.93 1 -43 2.20 2.05 2.34 2-60 3.59 5.69 6.96 wt. of ppt. mg. nil 131.5 251.7 257.0 124.4 210.8 255.7 257.2 256-8 256.8 Copper found mg. nil 19-66 37.54 38.43 18.61 3 1.52 38-23 38.46 38.41 38-41 * No sodium acetate buffer used in these experiments. DETERMINATION OF CADMIUM.-Cadmium sulphate AnalaR (9.6 g.) was The cadmium was The procedure adopted for the cadmium determinations was identical with dissolved in water and the solution was diluted to 2 litres.determined with anthranilic acid* (found cadmium 55.17 mg. per 25 ml.). that employed for copper. The results are given in Table 11. TABLE I1 Cadmium taken in each Experiment = 55.17 mg. Glacial acetic acid 111 1. 20 10 5 0.1 0.05 0.05 2N NaOH nil 3-15 3.37 3.95 5.92 6-47 6-82 7-17 M-t. of ppt. mg. nil 54.1 223.9 223.8 223.8 223.9 224.2 Cadmium found mg-nil 13.32 55-13 55-11 55.1 1 55-13 55.21 It will be observed that coniplete precipitation is obtained over the $H range 3.9 to 7.2. DETERMINATION OF ZIxc.-Zinc AnalaR (2-7 g.) was dissolved in the minimum quantity of nitric acid; the solution was made just alkaline with sodium carbonate and then just acid with acetic acid and diluted to 2 litres.The zinc u7as determined by the method of Funk and Ditt.* The method of precipitation washing and drying of zinc quinaldinate was similar to that employed for copper and cadmium. The results shown in Table 111 indicate that complete precipitation occurs over the range pH 2.3 to 6.5. The foregoing series of precipitations were also expressed graphically. The results show that copper-zinc separations are impossible by adjustment of $H, and that if any separation of copper from cadmium or of zinc from cadmium is possible it should be over the pH range 2.7 to 3-1. When sodium acetate buffer was employed it exerted a pronounced solubility effect; a parallel case is that of copper ant hr anilate 16 SHENNAY CJCINALDINIC ACID AS A REAGENT FOR COPPER ZINC AXD CADMIUfil TABLE 111 Zinc taken in each Experiment = 33.82 rng.Glacial acetic acid ml. 100 75 50 25 10 5 1 nil 0.1 2iV NaOH P H 1-72 1.96 2.10 2-30 2.75 3.09 3-52 5.43 6.45 U7t. of ppt. mg. nil 146.7 207.8 221-i 221.6 221.2 221.6 221.1 221.6 Zinc found mg. nil 22-27 31.i7 33-89 33.88 33-82 33.88 33.80 33-88 Experiments to separate copper from cadmium and zinc from cadmium were The conditions of precipitation washing and drying were essentially those The results are recorded in Table IV. made. employed in the separate determinations. TABLE I V Cadmium taken in each Experiment = 55.17 mg.Zinc or Glacial acetic copper taken acid mg. ml. 38-42 CU. 30 38-42 CU. 40 38.42 CU. 48 33.82 Zn. 25 33.82 Zn. 30 33.82 Zn. 40 PH wt. of ppt. mg. 3.1 1 268.8 2-93 262.0 2.69 259.0 2-85 240.0 2.60 239.1 2.30 236.9 Corresponding to copper or zinc mg. 40.20 CU. 39.18 CU. 38-74 CU. 36.70 Zn. 36-56 Zn. 36.07 Zn. High results were obtained in all experiments owing to co-precipitation of cadmium quinaldinate. In the separation of copper from cadmium co-precipitation varied from 0.8 to 4.5 per cent. over the $H range 2.7 to 3.1. In the separation of zinc from cadmium the results were inaccurate to the extent of 8 per cent. It is to be concluded from these results that while quinaldinic acid offers a convenient rapid and highly accurate method of determining copper zinc or cadmium separately it is unsuited for separation of these metals from one another. In conclusion I should like to thank Dr. A. J. Lindsey for the interest he has shown in this work. REFERENCES 1 . 2. 3. 4. 5. 6. 7. 8. P. R%y and M. K. Bose 2. anal. Chem. 1933,95 400. P. R%y and A. K. Majundar Id. 1935,100 324. P. R. R2y and M. K. Bose Mikrochem. 1935 17 11. P. R. R%yand J. Gupta Id. 1935 17 14. I>. K&y and M. K. Bose Id. 1935 18 89. M. Funk and M. Ditt 2. anal. Chem. 1933 93 242. R. J. Shennan J. H. F. Smith and A. M. W7ard ANALYST 1936,61 395. H. Funk and M. Ditt 2. anal. Chem. 1933 91 332. JEWRY STREET LONDON E.C.3 THE SIR JOHN CASS TECHNICAL INSTITUTE July 193

ISSN:0003-2654    

DOI:10.1039/AN9396400014

出版商:RSC    

年代:1939

数据来源: RSC

摘要:

\VILKISSON THE 171T,IMIN A -\NU TITAMIN D CONTESTS OF BUTTER 17 The Vitamin A and Vitamin D Contents of Butter 11. Seasonal Variation BY H. WILKINSON B.Sc. PH.D. (Rend at $he Meeting November 2 1938) IN a previous paper from this Laboratory (Morgan and Pritchardl) on the vitamin A and D contents of butter the assays of part of a series of Scottish butters were reported. This series has now been completed and the assay results together with those on a series of Danish butters form the basis of the present paper. The variation during the year in the vitamin A and D contents of butter was shown in the previous paper but the data were incomplete in that the dietary regime of the cows supplying the butter was not known and indeed in many cases the origin of the butter was also unknown.The present results are of interest in that in the Scottish series the rough feeding details and the origin and time of manu-facture are known whilst in the Danish series the time and place of manufacture are known although no feeding details are available. EXPERIMENTAL TEcmIQuE.-The vitamin A content of each butter was determined directly by means of the biological technique described by Morgan.2 The vitamin D content of some of the higher potency butters was determined directly on the butter. The method due to Xorgan3 was used. The basal vitamin D-free diet has been slightly modified as shown below: (Morgan) New diet Maize flakes (ground) . . 72 ti4 Meat meal (extracted) . . 1 12 Wheat gluten . . . . 19 -Salt mixture . . . . 4 4 __ Where the vitamin D potency was expected to be very low assays were made by means of the Bechdel-Hoppert alcohol-extraction method,* but it has been found that this method does not give complete extraction of the vitamin D a finding supported by other workers.Attempts were therefore made to determine the vitamin D content directly by incorporating the butter in the diet in place of part of the maize flakes. This method has proved satisfactory and has been used towards the end of the series. SCOTTISH BUTTERs.-Ariangernents were made with a creamery in Ayrshire t o send us a monthly sample of butter representative of the churning during 48 hours and dispatched to us as soon as possible. Details of the feeding practised by the farmers during the month represented by the sample were also sent to us.The district in which the creamery is situated lies between Rothesay Renfrew and Dumfries. To calculate the hours of sunshine daily a t the farms mentioned in this study the average of the average number of hours of sunshine daily fo 18 WILKINSON THE VITAMIN A AND VITAMIN D CONTENTS OF BUTTER: each of the three places mentioned above has been calculated and taken as representative of the district. The values used in the calculation have been obtained from the Weekly Weather Report Volume LIII (Meteorological Office), for the period March lst 1926 to February 2i’th 1937. These figures are shown graphically in Fig. 1. VITAMIN-A and -D POTENCY OF SCOTTISH BUlTERS 1936-37 Fig. 1 VITAMIN-A and -D POTENCY IN INTERNATIONAL UNITS PER GRAM OF 14 DANISH BUTTERS OCTOBER I936-DECEMBER 1937 1-.UC The vitamin A and D contents of the butters are given in Table I and shown The feeding details are gathered together in Table 11.in graphical form in Fig. 1. TABLE I VITAMIX-A AND VITAMIN-D POTEXCIES OF SCOTTISH BUTTERS 1936/3’i Vitamin -4 (International units, per g. of butter) February 1936 . . 14.S March 13.2 September October November December January, February March April May Vitamin D (International units, per g. of butter) 0.22 0.08 8::;) 0.08 0.60 0.99 0.60 0.so 0.40 0.20 0-30 0.08 0-1 1 0.13 0.08 0.12 0.6 11. SEASONAL VARIATION 19 TABLE I1 The number of farms supplying milk to the creamery each month and the number of farms on which the different foodstuffs were fed during the month.1936 Mar. Xpr. May June July Aug. Sept. Total No. o j Farms 9 8 6 6 6 7 6 Grass . . . . . - - 4 6 6 6 6 Concentrates . . 8 8 6 2 2 6 6 Straw . . . . . . 8 6 - - - - -Hay . . . . . . 9 6 - - - - -Turnips . . * 3 1 - _ _ - -Crushed oktts . . . I 3 1 - - - - 1 * . 4 3 - - - - - Beetpulp . Bean meal . . . . 1 - - - - - -. . 1 - - - - - - Maize . . . * * I - - _ - - _ Malt culrns . . . I - - _ - - - Lentil meal . . Barley meal . . . - l - - _ - _ -Screw pressed G.1J.O. Cabbage . . . . Green cut hay - 2 - - - - -Potatoes . . * 1 - - - - - 1 1 1 Marrow stem kale . . cake . . * * 1 - - - - - -- - - - - - -_ _ _ _ -Oct. Nov. Dec. 7 9 9 1 - -5 9 8 - 7 6 - 6 7 - 4 6 1 - -- 3 3 - 3 3 - - -- _ _ - 1 1 - - -- _ _ 1 - -- 1 1 1 1 1 3 4 -1937 v-7 Jan.Feb. Mar. Apr. May 7 9 7 7 7 7 7 9 7 7 7 5 6 6 6 -5 6 6 6 -3 4 5 2 -3 4 2 4 -3 4 3 2 -- 1 - - -2 1 1 1 -- - - - -- - - - -- - - - -DISCCSSION .-Vitamin A .-The highest and lowest vitamin A potencies encountered in this study are 29.9 u.p.g. in October 1936 and 8.0 u.p.g. in April, 1937 respectively. The average vitamin A potency during the summer months, when the animals received grass is 27.2 u.p.g. and the winter level is 13.8 u.p.g. The average value of the 16 samples assayed is 19.7 units of vitamin A per g. This value does not differ significantly from the average value reported by Morgan and Pritchard? The seasonal variation reported previously by many workers, is amply confirmed.It is evident that the vitamin A content of these butters undergoes a con-siderable increase immediately after the beginning of pasture feeding. The high level reached in June falls away in July August and September probably owing to deterioration in the quality of the pasture. However in October there is obtained a significantly increased vitamin A potency compared with the two previous months. This is due most probably to the flush of young grass that would occur in the pasture a t that period. This rise in the vitamin A potency of butter has been reported bef0re.l The cattle were taken from pasture at the end of October and the November sample shows an immediate and rapid fall which is continued through to December.This sample possesses about the normal vitamin A potency of winter butter. In 1937 there is again shown the sudden and rapid rise in the vitamin A potency of the butter when the cows go out to grass. In Table I1 are given the rough feeding details and various indications may be obtained from them: (i) Only during grass feeding is the vitamin A potency of the butter sig-nificantly increased 20 WILKINSON THE VITAMIN X AND VITAMIN D CONTENTS O F BUTTER: (ii) Although the peak in the vitamin A potency occurred in October only 4 out of 7 farms were feeding grass whilst in September all farms had their cows on pasture. The most probable explanation is that in October there occurs a flush of young grass in the pasture coupled with the feeding on the other 3 farms of marrow stem kale and green-cut hay, both probably richer in carotene than the grass obtainable in September.The high value in November is due possibly to the feeding on 4 farm&. of marrow stem kale. (iii) The winter feed is noticeably deficient in carotene the precursor of vitamin A. This applies especially to all materials except the concentrates, the carotene and vitamin A contents of which are not known and the green-cut hay. Definite conclusions are dificult to draw since the amounts fed per cow the milk yield and the amount of milk supplied to the creamery by each farm are unknown. Vitamin D.-The variations in the vitamin D content of this series of Scottish butters are perhaps even more profound than the vitamin A l-ariations. The highest potency was obtained in the June 1936 sample (0.99 unit of vitamin D per g.) and the lowest of 0.08 u.p.g.in March April and December 1936 and March 1937. The average summer value (i.e. while cows are out on grass) is 0.56 u.p.g. and the average winter value is 0.13 u.p.g. The average vitamin L) content for the 16 samples is 0.32 u.p.g. Consideration of Fig. 1 demonstrates quite clearly that the influence of the food on the vitamin D potency of the butter is negligible; the fall away is almost as rapid as the rise in potency although almost the same feeding regime was practised for a further 4 months after the peak in June. Campion et a1.5 have demonstrated that the vitamin D potency of butter varies directly with the amount of solar radiation which the cow receives.For this reason the approximate number of hours of sunshine per day have been calculated for the district around the farms supplying the milk. In Fig. 1 these values are shown graphically. However the effects of the feeding regime are well demonstrated. The following points are of interest : (i) Although the hours of sunshine in April and May in 1936 were high the vitamin D potency of the butter was low. The reason for the low April sample is that the cows were being stall-fed (i.e. indoors) during this month and did not go out to grass until the beginning of May. It is most probable that the increase in vitamin D potency of the butter lags behind the beginning of the solar radiation and this possibly accounts for the low vitamin D content of the May sample.The rapid increase in the May sample 1937 is due to the animals going out to grass about a fortnieht earlier than in 1936. (ii) The peak of the vitamin D potency in 1936 corresponds with the rnnximum number of hours of sunshine per day. (iii) The falling away in the vitamin D potency is very closely related to the drop in the number of hours of sunshine per day 11. SEASONAL VARIATION 21 I t may be concluded therefore in confirmation of the results of Campion et aZ.,6 that the vitamin D content of milk is due almost entirely to the ultra-violet irradiation that the cows receive. DANISH BuTTERs.-These are authoritative samples representative of Danish butter churned in the Jutland district of Denmark. No data about feeding or hours of sunshine are available.The vitamin A and D potencies are collected together in Table I11 and shown graphically in Fig. 2. TABLE I11 VITAMIN-A AND VITAMIN-D CONTENT OF Vitamin A (International units, Date per g. of butter) October 1936 . . 38.8 November ) . . 22.0 December a . 13.4 January 1937 . . 12.7 February , . . 16.9 March J ) ' * 10-8 April 7 * * 11.7 7 ' 18.4 34-2 9 * - 36.1 September , . . 41.8 October , . . 56.7 November , . . 33-8 May June I * -July August 9 - - -December , . . 23.7 DANISH BUTTER Vitamin D (International units, per g. of butter) 0.3 0.3 0.08 0.12 0.14 0.08 0.12 0.36 0-38 0.54 0.44 0.15 0.08 0.08 _-DIscussIoN.-Vitamin A .-The vitamin A content of this series of butters varies more widely than that of the Scottish butters.The highest potency was found in the October 1937 sample with 56.7 u.p.g. of butter. Incidentally this is by far the highest potency that has been obtained for butter in this laboratory, the next highest being 41.8 u.p.g. shown in the previous month's sample (September, 1937). The lowest potency (10.8 u.p.g.) was shown in the sample of March 1937. The average winter vitamin A potency is 18.1 u.p.g. (8 samples) which is higher than that reported for the Scottish butters (13.8 u.p.g.). This is due to the very high potencies of the last 2 samples received in November and December 1937. The average vitamin A potency of the 14 samples is 26-5 u.p.g. which is higher than the averages of the 16 samples of Scottish butter described earlier in this paper and of the 75 samples of various butters described by Morgan and Pritchard.1 No feeding details are available so that discussion of the results from this angle is impossible.The rise in potency in October noted previously in our work on butter has been obtained but unfortunately the August sample was not received so that it is not possible to tell whether there was a fall in potency in September before the October increase. However the general trend of the results follows previous experience. Vitamin D.-A variation in vitamin D content similar to that previously reported has been obtained in this series of butters. The range however is no 22 WILKINSON THE VITAMIN A AND VITAMIN CONTENTS OF BUTTER as wide as in the Scottish butters the lowest level being the same (0.08 u.p.g.in December 1936 and 1937 March and November 1937) but the highest level (0.54 u.p.g.) is only about half the highest Scottish level and is reachedin July 1937. The amount of sunshine may of course have been less in Jutland in 1937 than in Scotland in 1936. The average winter level is 0.12 u.p.g. and the summer level 0.36 with an average over the year (14 samples) of 0.23 u.p.g. CALCULATION OF ERRORs*.-Each assay is calculated from the mean of the “pair differences.” The standard deviation (0) of the pair differences of each assay is given by : 0 = PX n - 1 - M)e> JF where x = a pair difference n = number of pairs M = mean, the limits on either side of the mean within which two-thirds of the pair differences could be expected to lie being given by M & 6.Similarly the standard deviation of a group of m assays will be: where N = total number of pair differences ( = En) This value can be used to estimate the “probable error” of the assays themselves, 2.e. the percentage limits of the assay within which there is 1 chance in 2 that the true assay lies by combining it with the growth/dosage equation in the case of the vitamin A tests and the healing/dosage equation in the case of the vitamin D tests. Besides the probable error (P.E.) two other standards are in common use, uiz. 2 x P.E. which gives the limits within which there are 21 in 22 chances of truth and 2.576 x P.E. which gives the limits of 99 in 100 chances. This latter error written usually as “limits of error (P = 0.99),” has been adopted in the British Pharmacopoeia Addendum 1936.All three methods of expression are given below for the four groups of assays. Although the average number of pairs used per test was 9 the errors have been calculated on 10 pairs this being the standard number. TABLE IV PERCENTAGE ERROR WITH 10 PAIRS OF RATS PER TEST Vitamin- A Assays Scottish butters Danish butters P.E. +7 -6 +7 -7 3 P.E. . . +21 -17 +24 -19 P = 0.99 . . +28 - 22 +31 -24 Vitamin-D Assays Scottish butters Danish butters P.E. . . +9 -8 +9 -8 3P.E. +29 -22 +28 -22 P = 0.99 +39 -28 +38 -27 *Cf. Coward ANALYST 1934 59 681 MCNAUGHT THE DETERMINATION OF COBALT IN ANIMAL TlSSUES 23 For biological tests these errors may be considered very satisfactory. They are considerably smaller than the representative “limits of error (P = 0.99)’’ quoted by the B.P.Addendum which are: For vitamin A assays (10 pairs) + 239 per cent. - 70 per cent. Y Y > J J (lo ) J ) + ‘15 9 ) t > - 51 Y 9 9 ) SUMMAHY.-TWO series of butters taken at monthly intervals one in Scotland and the other in Denmark have been assayed for vitamin A and vitamin D. The typical monthly variation is shown in both series the highest vitamin A value being obtained when the cows are on grass. One sample (October 1937) in the Danish butter series has a vitamin A potency of 66.7 u.p.g. which is the highest potency recorded in this laboratory. The variation in the vitamin D potency of the Scottish butters has been related to the variation in the amount of sunshine received by the cows on pasture. It has not been possible to do this for the Danish butters owing to lack of the necessary data. The percentage error of the assays has been calculated. I wish to thank the directors of Lever Brothers & Unilever Ltd. for permission t o publish these results. 1. 2. 3. 4. 6. FOOD May, REFERENCES R. S. Morgan and H. Pritchard ANALYST 1937 62 364. R. S. Morgan Biochem. J. 1934 28 1178. H. E. Bechdel and C. A. Hoppert J. Nutrition 1936 11 337. J. E. Campion K. M. Henry S. K. I b n and J . Mackintosh Biochem. J . 1937,31 81. RESEARCH LABORATORY - I d . 1932 26 1144. LEVER BROS. & UNILEVER LTD. PORT SUNLIGHT 193

ISSN:0003-2654    

DOI:10.1039/AN9396400017

出版商:RSC    

年代:1939

数据来源: RSC

摘要:

426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents.It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate.There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively.Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited.The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation.Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE.By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time.The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice.Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years.The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion.The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on.Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation.Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp.15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction

ISSN:0003-2654    

DOI:10.1039/AN9396400023

出版商:RSC    

年代:1939

数据来源: RSC

摘要:

426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents.It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate.There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively.Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited.The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation.Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE.By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time.The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice.Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years.The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion.The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on.Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction

ISSN:0003-2654    

DOI:10.1039/AN939640027b

出版商:RSC    

年代:1939

数据来源: RSC

摘要:

426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents.It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate.There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively.Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited.The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction

ISSN:0003-2654    

DOI:10.1039/AN9396400031

出版商:RSC    

年代:1939

数据来源: RSC

摘要:

426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents.It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate.There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively.Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited.The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation.Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE.By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time.The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction

ISSN:0003-2654    

DOI:10.1039/AN9396400032

出版商:RSC    

年代:1939

数据来源: RSC

摘要:

426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents.It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate.There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively.Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited.The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation.Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE.By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time.The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice.Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years.The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion.The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on.Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction

ISSN:0003-2654    

DOI:10.1039/AN9396400035

出版商:RSC    

年代:1939

数据来源: RSC

摘要:

426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents.It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate.There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively.Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited.The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation.Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE.By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time.The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction

ISSN:0003-2654    

DOI:10.1039/AN9396400038

出版商:RSC    

年代:1939

数据来源: RSC