142 THE ANALYST. ON THE ANALYSIS OF BUTTER FAT. B Y FRANK P. PERKINS, Pllblic ~ ~ ? ~ d t J s t . ~ O T Ex&,*. HITHERTO the determination of the volatile as well as the non-volatile acids, contained in butter, has generally been accomplished in the gravimetric way. Satisfactory, however, as the processes which have been devised in this direction may be, there is little doubt tliiit they are somewhat tedious to perform ; and although where the greatest accuracy is required, analysis by weight must always rank the highest, yet 1~ fairly accurate volumetric method, easily and rapidly executed, must be a desideratum. A few steps towards this e d have already been made.In the first volume of THE ANALYST theye is a paper by Dr. Dupr6 devoted principally to the volumetric estimation of the volatile acids in butter, and in a paper lately published in the same journal by Dr.Koettstorfer, the author proposes to determine the noiz-volatile acids volumetrically. About a year ago, I showed how the amount of volatile acids may be approximately ascertained by taking the acid filtrate derived from the insoluble acids, titrating a, portion of it with K Ho to determine total acidity, evaporating another known portion to small bulk, titrating again, and then converting the difference between the two experiments to butyric acid.I have now made a further advance. On referring to Messrs. Angel1 and Hehner’s treatise 011 (‘ Butter,” it will be found that the endeayonr to obtain the amount of volatile acids by saponifying the fat and then distilling with sulphuric acid, mas futile, the distillation was difficult to manage, and the results unsatisfactory; but I find that, by liberating the fatty acids with oxalic acid this difficulty is overcome, and I believe that the method now proposed will be found simple, workable, and fairly accurate.Weigh out 1 to 2 gramines of purified butter fat, saponify in a beaker in the usual way, drive off the alcohol, cool, set free the acids by adding a cold saturated solution of oxalic acid in very slight excess, pass through a small filter, previously moistened with water, wash the insoluble acids thoroughly, first by decantation with cold, and lastly with hot water on the filter, make up the filtrate to, say, 200 c.c., transfer 100 C.C.to a small retort connected with a condenser and distil slowly until the 2oAoEc has passed over, add a few drops of litmus solution, titrate with deci-normal K Ho, calculate the amount consumed by the volatile It is as follows.THE ANALYST.143 acids in 100 grammes of fat, and translate to butyric acid { C C3H7 0 Ho. Tlie insoluble acids on tlie filter are treated witli hot, ,zlcoliol, tlie fluid holding the acids in solution being received iii it flask.Tlie filter is washed witli alcohol until it 110 longer reddens litmus, and the filtrate is made 111) to 100 C.C. with alcohol. Half of tliis is taken, coloiired with a suitable inclicittor, and heated gently ; deci-normal K Ho is run in and tlie number of cubic ceiitimctres required for neutralization noted, tlie second portion is similarly treated.Tlie first experiment serves as a guide to coloiir, &c. ; tlie number of cnbic centimetres used is nscertaiuecl, niid the amount required by the non-volatile acids in 100 grammes of fat calculated, For tlie purpose of comparisou with fats used as achdterants, it may, perliaps, be coiivenieiit to coiivert tliis to stearic Eqwrinlclct 2.-1-351 grammes of purified fat from good farm butter was takeii, The solntioii containing tlie volatile slcicls wits made 111) to 300 C.C.Tlie distillate from 100 C.C. required 8.5 C.C. KHo. Tliis on 100 grammes of fat gave 4-31 KHo or 6-7 butyric acid. Expcriincitt 2.-Tlic alcoliolic solution containing tlie iioii-volatile acids of tlie above was made up to 100 C.C. This on 100 grammcs of fat gave 18.14 KHo or 92.0 stearic acid.I;I,qJei*ir~rent 3.-1.19 grammes of fat from another sample of the same class mas tdien. The solution containing the volatile acids measured 170 C.C. Tlie distillate from 100 C.C. required 5.6 C.C. KHo. Tliis calculated 011 100 grammes of fat gave 4.122 I< 110 or 6.8 bntyrk acid. E.q~o.irnent 4.-The alcoliolic solution coiitaining the noii-yolatile acids of tlie above required 38.5 C.C. K Ho. This on 100 grammes of fat gave 18- K Ho or 91.7 stearic acid. 43.8 C.C. of I< Ho were required. These results agree closely witli tliose obtained by Dr. Koettstorfer. Tlius- Per ccnt. of K Ho. Experiment 1. -Volatile acids 4.31 Experiment 2,--Non-volatile 18.14 22-45 Experiment 3,--Volatile acids 4.42 Experiment 4.-Non-volatilc 18.0 - 23.42