Since As+3 and As+5 form  stable hydrides that have ionization potentials of 10.5 eV, it can be detected using a photoionization detector that has a lamp energy of 10.6 eV. Photoionization has been coupled to hydride generation and shown to be a very sensitive technique by a number of researchers to determine arsenic in natural waters at low or sub ppb concentrations. The disadvantage of this technique is that it uses a liquid nitrogen trap to concentrate the arsine. We have modified that method by eliminating the liquid nitrogen and using a new PID that improves the detection limit by up to 10 fold. We can detect arsenic down to 0.1 ppb. We have applied this method to the analysis of water, juices and rice.The hydride generation minimizes any sample preparation, and the GC is used to separate arsenic from other metal hydrides and their organic counterparts.

New analytical method for low level detection of arsenic in food and beverages

248th National Meeting (2014)

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