The Development of New Methods for the Analysis of Glutathione and Mercury Species Enabled Through Speciated Isotope Dilution Mass Spectrometry

摘要

When the body is exposed to mercury, in all of its speciated forms, there are toxic effects. These effects include neurological, respiratory, and cardiovascular damage. As a result of these toxic effects, the state of California has lowered the limit of detection (LOD) for Hg2+ and methylmercury to 0.2 ppt and 0.02 ppt respectively. The speciated measurement of 0.02 ppt is a level not yet achieved in the literature. Therefore, a new instrument was built in conjunction with ICP-MS using EPA Method 6800 for quantification of the species. This research and instrumentation development describes the progress thus far to enable sensitivity in the nanogram and sub-picogram region for mercury quantification. The body has various mechanisms to rid itself of toxins, such as mercury and other heavy metals. One essential method is using the molecule glutathione to bind and transport mercury from the body via the kidneys in a phase II detoxification mechanism. Quantifying the ratio of reduced glutathione (GSH) and oxidized glutathione (GSSG) is an indicator of health for an individual's immune system. A parameter not previously accounted for during quantification of glutathione in blood, which is appearing in saliva, is the digestive enzymes. These enzymes can hydrolize the peptide bonds of glutathione during shipment and lead to the loss of detection of both the isotopically spiked and natural abundant molecule. Development of a method to increase analyte stability in saliva is one improvement being researched in this study. Preliminary results show that stability can be achieved by adding acetonitrile to the samples in the field during acquisition.