Arsenic speciation analysis in human saliva.
BACKGROUND
Determination of arsenic species in saliva is potentially useful for biomonitoring of human exposure and studying arsenic metabolism. Arsenic speciation in saliva has not been reported previously.


METHODS
We separated arsenic species in saliva using liquid chromatography (LC) and quantified them by inductively coupled plasma mass spectrometry. We further confirmed the identities of arsenic species by LC coupled with electrospray ionization tandem mass spectrometry. These methods were successfully applied to the determination of arsenite (As(III)), arsenate (As(V)), and their methylation metabolites, monomethylarsonic acid (MMA(V)), and dimethylarsinic acid (DMA(V)), in >300 saliva samples collected from people who were exposed to varying concentrations of arsenic.


RESULTS
The mean (range) concentrations (microg/L) in the saliva samples from 32 volunteers exposed to background levels of arsenic were As(III) 0.3 [not detectable (ND) to 0.7], As(V) 0.3 (ND to 0.5), MMA(V) 0.1 (ND to 0.2), and DMA(V) 0.7 (ND to 2.6). Samples from 301 people exposed to increased concentrations of arsenic in drinking water showed detectable As(III) in 99%, As(V) in 98%, MMA(V) in 80%, and DMA(V) in 68% of samples. The mean (range) concentrations of arsenic species in these saliva samples were (in microg/L) As(III) 2.8 (0.1-38), As(V) 8.1 (0.3-120), MMA(V) 0.8 (0.1-6.0), and DMA(V) 0.4 (0.1-3.9). Saliva arsenic correlated with drinking water arsenic. Odds ratios for skin lesions increased with saliva arsenic concentrations. The association between saliva arsenic concentrations and the prevalence of skin lesions was statistically significant (P <0.001).


CONCLUSIONS
Speciation of As(V), As(III), MMA(V), and DMA(V) in human saliva is a useful method for monitoring arsenic exposure.
Yuan
Chungang
C
Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada.
Lu
Xiufen
X
Oro
Nicole
N
Wang
Zhongwen
Z
Xia
Yajuan
Y
Wade
Timothy J
TJ
Mumford
Judy
J
Le
X Chris
XC
D000328:Adult; D001149:Arsenates / Q000032:analysis / Q000633:toxicity; D020261:Arsenic Poisoning / Q000209:etiology; D001152:Arsenicals / Q000032:analysis*; D018053:Arsenites / Q000032:analysis / Q000633:toxicity; D002101:Cacodylic Acid / Q000032:analysis / Q000633:toxicity; D002853:Chromatography, Liquid; D004781:Environmental Exposure / Q000009:adverse effects; D005260:Female; D005618:Fresh Water / Q000737:chemistry; D006801:Humans; D008297:Male; D013058:Mass Spectrometry / Q000379:methods; D008875:Middle Aged; D012015:Reference Standards; D012463:Saliva / Q000737:chemistry*; D012871:Skin Diseases / Q000139:chemically induced
D001149:Arsenates; D001152:Arsenicals; D018053:Arsenites; D002101:Cacodylic Acid; C020300:monomethylarsonic acid