Elimination of the chloride interference on the determination of arsenic using hydride generation inductively coupled plasma mass spectrometry.

In the determination of arsenic, attention has recently focused on the speciation of As(III) and As(V). Reversed-phase HPLC can be used to efficiently separate these two arsenic species. When inductively coupled plasma mass spectrometry is used for arsenic detection, an isobaric interference at m/z 75 is caused by the presence of chloride in the sample. These experiments describe the use of hydride generation in conjunction with a polypropylene-membrane gas-liquid separator to completely eliminate the transport of chloride to the plasma. A detection limit of 0.46 ppb for As(III) was achieved with this system. The chromatographic resolution of the system was not compromised by the addition of the gas-liquid separator. A determination of the arsenic content of a NIST urine sample was performed to demonstrate the effectiveness of the chloride elimination.