Determination of arsenic species by high-performance liquid chromatography-inductively coupled plasma mass spectrometry
Arsenic(III), AsV, monomethylarsonic acid (MMAA), dimethylarsinic acid (DMAA) and arsenobetaine (AsB) were separated by high-performance liquid chromatography (HPLC) and determined on-line by inductively coupled plasma mass spectrometry (ICP-MS). Two forms of HPLC were used: ion pairing and ion exchange, with absolute detection limits for arsenic ranging between 50 and 300 pg. These detection limits were independent of the arsenic species when peak area was used for quantification. Anion pairing was found generally to be more sensitive to changes in the matrix of the sample injected. Anion exchange was more tolerant because of the higher buffering capacity of the mobile phase. Cation pairing was found suitable for the determination of DMAA and AsB in a biological sample containing high concentrations of salts.