Flame AAS determination of total chromium in mussel samples using a continuous ultrasound-assisted extraction system connected to an on-line flow injection manifold

Total chromium was extracted on-line from solid mussel samples using a simple, rapid, and continuous ultrasound-assisted extraction system (CUES). CUES is connected to a flow injection manifold, which permits the on-line flame atomic absorption spectrometric determination of chromium. The manifold for total chromium determination is the simplest possible because a volume of 83 muL of acid leachate was injected into a water carrier stream. An experimental design was used for optimization of the continuous leaching procedure: Compared to off-line ultrasonic-assisted extraction methods, the sonication time was reduced by a factor of 4-28. The method allowed a total sampling frequency of 11 samples per hour, with a relative standard deviation for the complete procedure of 1.7% [for a sample containing 2.9 mug/g chromium (wet mass)]. Accuracy was verified using TORT-1 certified reference material and the procedure applied to the analysis of mussel samples.