Determination of six arsenic species in human urine by HPLC-ICP-MS

Objective To establish an High Performance Liquid Chromatography-Inductively Coupled Plasma-Mass Spectrometry （HPLC-ICP-MS） method for determination of six arsenic species in human urine，including arseniccholine （AsC）， arsenobetaine （AsB）， arsenite （As³⁺）， dimethylarsinic acid （DMA⁵⁺）， monomethylarsonic acid （MMA⁵⁺）， and arsenate （As⁵⁺）.

Methods The pH value of mobile phase and the content of anhydrous ethanol were optimized. Ammonium carbonate （50 mmol·L^-1， containing 2% anhydrous ethanol， pH-8.5） mobile phase was selected. Cl^- interference was eliminated by He mode. The arsenic species in 10-fold diluted human urine samples were separated by an Hamilton PRP X-100 anionic column. A method for the determination of six arsenic species was established.

Results Six arsenic species could be separated in 13 minutes. The linear correlation coefficients were above 0.999. The limits of detection were 0.10‒0.20 μg·L^-1， and the limits of quantification were 0.30‒0.50 μg·L^-1. Precision experiments showed that RSD ranged from 5.96% to 9.07% when adding concentration 0.20 μg·L^-1； from 2.48% to 6.38% when adding concentration 2.00 μg·L^-1； and from 1.41% to 2.57% when adding concentration 5.00 μg·L^-1. Accuracy test showed that the recoveries were 80%‒125%.

Conclusion The established HPLC-ICP-MS method for determination of six arsenic species in human urine is rapid， accurate and sensitive. It can be applied to the determination of arsenic species in human urine.