This is a 1974 photo from my first lab, with Canada Fisheries in Newfoundland, Canada. We were measuring arsenic in water, fish tissue, sediments, etc, by distillation of arsine into a solution of diethyldithiocarbamate in pyridine. The color was measured at 520 nm. We could detect 0.3 +/- 0.1 micrograms. The only interference was from antimony (which max'd at 500 nm). I adapted the method from one in Standard Methods for Water and Wastewater.

The hood was homemade and drew away the large amounts of hydrogen produced, plus the pyridine stink.

People said to us, why didn't you use AA or some other fancy instrumental method? The reasons were (a) this method was far more sensitive than FAA, and ICP was not a thing yet, and (b) we could turn over three racks of 20 samples per day, or 60 samples, without breathing hard, much faster than we could prepare samples.