Simultaneous determination of glycine betaine and arsenobetaine in biological samples by HPLC/ICPMS/ESMS and the application to some marine and freshwater fish samples

• We report a method for the determination of glycine betaine and arsenobetaine.
• The method covers a broad concentration range of both analytes simultaneously.
• We applied the method to various marine and freshwater fish.

We describe a HPLC/mass spectrometry method for the simultaneous determination of glycine betaine and arsenobetaine in biological samples. The sample preparation included a water/methanol extraction followed by clean-up of extracts on a strong cation-exchange resin; the HPLC system consisted of a cation-exchange column with an ammonium formate buffer solution as mobile phase. Glycine betaine and arsenobetaine were quantified in a single chromatographic run by splitting the HPLC flow with an adjustable flow splitter and detecting glycine betaine selectively by electrospray MS in the positive single ion monitoring mode at m/z 118, and arsenobetaine with the arsenic-selective detector ICPMS at m/z 75. The proposed method was validated for arsenobetaine by analysis of CRM Dorm-2, and for glycine betaine by spiking the CRM Dorm-2 with a defined amount of glycine betaine. Finally, the developed method was applied to determine glycine betaine/arsenobetaine ratios in single specimens of four species of marine fish and one species of freshwater fish.