Study of the Possible Benefits of Flow Injection Sample Introduction for Flame Atomic Absorption Spectrometry

Flow injection techniques for use with atomic spectrometry are briefly reviewed, from which it is apparentthat there has been a considerable increase in interest recently in on-line pre-concentration and matrixisolation methods. In addition to the use of immobilised reagents and solvent extraction, methods based onprecipitation and collection of the precipitate in the manifold have been reported. The possible benefits ofrunning the nebuliser under starvation conditions both with and without air compensation are examinedtogether with the benefits of peak-area as opposed to peak-height measurements, claimed in some previousstudies to lead to improved detection limits. It is shown that with a Baird Atomic A3400 nebuliser thedepressive effect of phosphate on calcium may be removed at low flow-rates and that with a Philips SP9nebuliser the best detection limits are obtained when strategies for maximising the peak height are adopted.Preliminary results for the generation of a volatile metal chelate (copper trifluoroacetylacetonate) as the basisfor matrix isolation show a considerable improvement in peak-area sensitivity over conventionalnebulisation, although the peak-heig ht sensitivity is similar

Flow Injection Analysis Techniques of Method Development for Flame Atomic Absorption Spectrometry

The flow injection introduction of samples that would be difficult by conventional nebulisation owing to dissolved solid content, viscosity or quenching effects on flame reactions is demonstrated. The various ways of achieving sample dilution by control of volume injected, tube dimensions and flow-rate are discussed and a manifold described for producing solutions for calibration purposes and diluting off-range samples. The important characteristics of the nebuliser and instrument for flow injection work are evaluated. A simple manifold for investigating interference effects is described and its use illustrated for some well known effects. The possibilities of achieving pre-treatment by solvent extraction and extension to include indirect methods are discussed and the role of flow injection procedures in the method development for, and the extension of the range of application of, flame atomic-absorption spectrometry is critically evaluated

Production of Sodium Cyanide from Cassava Wastes

ABSTRACT An acid hydrolysis method of cyanide release from cyanogenic glucosides in cassava was investigated for the release of cyanide ion (CN -) to be used for the production of sodium cyanide from cassava. The released cyanide was fixed in Sodium Hydroxide after hydrolysis. Sodium cyanide was crystallized from the slurry by maintaining the temperature between 60 0 C and 70 0 C in a drying oven. Characterization of NaCN was done via the Deniges' modified silver nitrate titration. Cyanide concentrations between 140mg CN/50g to 342mgCN/50g of sample were obtained. The yield range was 0.28% -0.68%