Analytical system for arsenobetaine and arsenocholine speciation

Arsenobetaine (AsBe) and arsenocholine (AsCo) were determined with an HPLC-ultrasonic nebulization (USN)-AFS system. Several parameters, viz., the argon and hydrogen gas flow rates, the eluent buffer concentration, the eluent pH, the loop volume and the nebulization temperature, were investigated and optimized. HPLC-thermospray MS was used to verify the HPLC-USN-AFS results. The detection limit of the method was 6.7 ng for AsBe and 8.2 ng for AsCo. The method was applied to the determination of AsBe and AsCo in tap water and freshwater carp samples using standard additions; the recoveries were 95-102%.