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An atomic absorption spectrometric method has been used for the determination of lead and manganese additives in gasolines. Using a pre-heated Pyrex reactor, gasoline samples and standards are volatilised and introduced into the flame, in the vapour phase, by a nitrogen carrier gas flow. The detection limit for manganese with this method is 0.3-1 p.p.m. and in the order of 2 p.p.m. for lead. Results obtained for the analysis of commercial gasoline samples by the recommended procedure are compared with a reference method. Resultsfor manganese additives are similar to those obtained through emulsification of the samples. For lead additives it is necessary to use a calibration graph prepared for samples of the same type which had been analysed previously. For this reason caution must be taken in applying the method indiscriminately to the determination of lead in gasoline from sources which have not been characterised.

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Different co ba It complexes with 6-d i ketones, dit hiocarbamates and 8-hydroxyqu i no1 i ne were evaluated for the direct determination of cobalt by flame atomic absorption spectrometry with vapour-phase sample introduction. The order of sensitivity is COCo(TFA),, where Ox = 8-hydroxyquinoline, PDC = tetramethylenedithiocarbamate (pyrrolidinedithiocarbamate), AA = acetylacetone, HFA = hexafluoroacetylacetone, DTC = diethyldithiocarbamate and TFA = trifluoroacetylacetone. The sensitivity of Co(TFA), expressed as the slope of the Cali bration graph is 0.502 ng-1, with a reproducibility varying between 0.6 and 2.5% (relative standard deviation). Two simple volatilisation systems that can be adapted to conventional instrumentation, have been designed. The most sensitive method was applied to determine cobalt in steel, bronze and brass, with good results.