Comparison of conventional and fast thermal programme approaches for determination of total and extractable Cd in sediments by electrothermal atomic absorption spectrometry following sequential extraction

Abstract

Conventional and fast thermal programmes are optimised so that determination of total and extractable Cd according to the Bureau Reference of Standards (BCR) sequential extraction scheme (SES) can be performed using aqueous standard calibration. Matrix effects arising from the different reagents corresponding to the above scheme were checked by constructing pyrolysis–atomisation curves. Using the appropriate matrix modifier and amount of it, platform atomisation, optimised thermal programmes (conventional or fast programmes) and D2-background correction, an improved methodology is proposed as compared with the existing one recommending the standard additions technique for calibration. Quantitative Cd recoveries could be attained when hot injection and omission of the pyrolysis stage were implemented even in the absence of a Pd matrix modifier. After validation with a CRM certified in extractable metals according to the BCR scheme (original and modified), an application to two river sediments is presented.