Numerous methods have been described in the literature for the determination of arsenic both in water and in particulate matrices. Many of these methods essentially employ the same principles, but apply different reagents, concentrations or instrumentation. The most popular techniques for arsenic analyses include hydride generation and AA, ICP-OES or ICP-MS. Although many water labs have these types of spectrometers already, many labs do not. The cost of these types of spectrometers is in the $100-200K price range.
Many labs would have to choose the older colorimetric methods but we have developed and modified the PID and GC-PID methods for arsenic in water analysis at ppb levels (1) to work with food and juice. The system cost is a fraction of the $100K spectrometer price.