i V SUMMARIES OF PAPERS IN THIS I S S U E December, 1979Summaries of Papers in this IssueAbsorptiometric Determination of Low Oxygen Concentrations inPower-station Waters. Part I. Manual MethodA simple, fast method for determining low concentrations of oxygen inpower-station waters has been developed, based on the reaction of dissolvedoxygen with the leuco-base of methylene blue to give a soluble blue oxidationproduct the absorbance of which is a function of the oxygen concentration.A special glass cell has been devised, which acts sequentially as a sample-collection vessel, a reaction vessel and a spectrophotometric cuvette. Thecell design permits the easy addition of the leuco-base and also the air-saturated water used for calibration. A novel technique of “zero-timeextrapolation” for the determination of the reagentlcuvette blank circumventsthe difficulty of making this measurement with oxygen-free water.The calibration graph is linear up to 50 pgl-l, but satisfactory measure-ments may be made up to 100 p g 1-l.The criterion of detection is approxi-mately 1.0 pg 1-1 with standard deviations ranging between 0.4 and 1.7 pg 1-1,depending on the concentration. The analysis time is 5-10 min for a singledetermination.Iron(I1) and copper(I1) ions are the only ions likely to be present in boilerwaters that cause serious interference and these must be removed beforeanalysis by passing the water sample through a cation-exchange column.Keywords ; Oxygen determination ; absovptiovlzetry ; water analysis ; manual!analysisG.I. GOODFELLOW and H. M. WEBBERCentral Electricity Research Laboratories, Kelvin Avenue, Leatherhead, Surrey,KT22 7SE.Analyst, 1979, 104, 1105-1118.Absorptiometric Determination of Low Oxygen Concentrations inPower-station Waters. Part 11. Continuous Automatic MethodUsing the Technicon AutoAnalyzerA continuous automatic method for the absorptiometric determination oflow oxygen concentrations in power-station waters using the TechniconAutoAnalyzer is described.Keywords : Oxygen determinution ; absovptiometry ; water analysis ; continuousanalysisG. I. GOODFELLOW, D. F. LIBAERT and H. M. WEBBERCentral Electricity Research Laboratories, Kelvin Avenue, Leatherhead, Surrey,KT22 7SE.Analyst, 1979, 104, 1119-1123vi SUMMARIES OF PAl3ERS I N THIS ISSUESingle Reagent Method for the S:pectrophotometric Determinationof Phosphorus in SilicatesDecember, 1979A method has been developed for the spectrophotometric determination ofphosphorus in silicate rocks following fusion with a lithium borate flux anddissolution of the melt in dilute nitric acid.By using a single reagentincorporating antimony and relatively high concentrations of ascorbic acidand hydroxylammonium chloride, a stable colour has been achieved. Thecolour is fully developed within 30 min and is stable up to 4 h in solutionscontaining up to 0.8 pgml-1 of phosphorus(V) oxide with nitric acid con-centrations not greater than 0.04 N. Beer’s law is obeyed and E = 22 200a t 880 nm.Keywords : Phosphorus determination ; silicate rocks ; spectrophotonzetry ; singlereagent method; molybdonntimony1;t)hosphoric acidP.J. WATKINSGeology Department, Imperial College of Slcience and Technology, London, SW7 2BP.Analyst, 1979, 104, 1124-1 128.Modified Colorimetric Method for the Determination of MalathionA thorough investigation has been made of the recommended method for thedetermination of malathion, and the rnajor cause of two of the most seriousproblems in this method has been resolved. The method that uses acopper(I1) complex as the basis of colorimetric measurements suffers fromthe disadvantage that the colour fades quickly and that an increase of a fewseconds in the contact time of the copper(I1) solution and the hydrolysisproduct of malathion results in a reduction in the intensity of the yellowcolour.Attempts to overcome these drawbacks have been reported, someof which are tedious and others only partially successful, but it is suggestedthat if copper is replaccd with bismuth the problems may be more simplyresolved. Isomalathion does not react in this method.Keywords : Malathion alkaline hydrolysis ; malathion determination ; copperchelate colorimetry ; colour instabiliiy ; bismuth chelateE. R. CLARK and I. A. QAZIDepartment of Chemistry, University of Aston in Birmingham, Gosta Green,Birmingham, B4 7ET.Analyst, 1979, 104, 1129-1134.Histochemical Identification of Commercial Wheat GlutenThree methods for the microscopical identification of commercial wheatglutens are compared.A periodic acid - Schiff and an iodine - potassiumiodide method both indicate gluten by showing the wheat starch present.Toluidine blue contained in an aqueous mountant distinguishes gluten proteinfrom both soya and meat proteins. Each method identified commercialgluten present in a gluten - soya protein - meat mixture. Testing for bothstarch and protein is recommended for protein products that may containadded starch.Keywords : Commercial wheat gluten identification ; gluten - soya mixture ;gluten - soya - meat mixtureF. 0. FLINT and R. F. P. JOHNSONProcter Department of Food Science, University of Leeds, Leeds, LS2 9JTDecember, 1979 SUMMARIES OF PAPERS I N THIS ISSUEInvestigation of Atomiser Tube Design for Carbon FurnaceAtomic - emission SpectrometryviiModifications to a standard graphite furnace tube, designed for atomic-absorption measurements, are shown to give improved performance foratomic-emission measurements of a number of elements.Four differentmodified tubes are compared with a standard Perkin-Elmer HGA-72 graphitetube with respect to their thermal characteristics and the detection limits often selected elements of varying atom-appearance temperatures. Differentelements were found to give lowest detection limits in tubes of differentdesign. The results indicate the need for a new approach to tube design,specifically for atomic-emission measurements, in order that best detectionlimits can be achieved for all elements in a single graphite tube.Keywords : Modijied atomiser tubes ; atomic-emission spectrometvy ; carbonfurnace atornisationD.LITTLEJOHN and J. M. OTTAWAYDepartment of Pure and Applied Chemistry, Iinivcrsity of Strathclyde, CathcdralStreet, Glasgow, G1 1XL.Analyst, 1979, 104, 1138-1 150.Separation of Bismuth-210 and Polonium-210 from AqueousSolutions by Spontaneous Adsorption on Copper FoilsA description is given of factors controlling the adsorption of trace amountsof radioactive bismuth and polonium from aqueous solution on to thincopper foils. Optimum conditions are defined for the selective and quantita-tive adsorption of bismuth-210 and polonium-2 10 from aqueous solution andfor a subsequent desorption process to give separation of the extractedbismuth and polonium.The method is demonstrated to be suitable for thepreparation of thin sources for a-spectroscopy and for analysis of bismuth-210and polonium-210 in marine sediments. The kinetics of the adsorption anddesorption processes are briefly discussed.Key words : 210Pb, 210Bi and 210Po analysis ; spontaneous adsovption ; desovp-tion ; copper suvfacesA. B. MacKENZIE and R. D. SCOTTScottish Universities Research and Reactor Centre, East Kilbride, Glasgow,G75 OQU.Analyst, 1979, 104, 1151-1158.Determination of Mercury in Smelter Flue Dusts byAcid Digestion MethodsIn order to develop a mercury digestion method suitable for flue dust fromnon-ferrous and secondary lead smelters, seven acid digestions, two in aclosed system and five in an open system, were studied. Closed systemswere less convenient to use and had no real advantage over open systems.We conclude that the use of aqua regia in open systems is the most effectivedigestion method. A 96% recovery for spiked mercury(I1) sulphide andmercury(I1) oxide and a 98% recovery for mercury(I1) chloride were obtained.Keywords : Mevcuvy determination ; acid digestion ; ftue dust ; non-fervoussmelterCHUNG H. CHIU and JOHN C. HILBORNChemistry Division, Environment Canada, Air Pollution Technology Centre, RiverRoad, Ottawa, Canada, K1A 1C8.Analyst, 1979, 104, 1159-1 164