Instrument: Gas Chromatograph
Instrument separating gases, volatile substances, or substances dissolved in a volatile solvent by transporting an inert gas through a column packed with a sorbent to a detector for assay. (from SeaDataNet, BODC)
Processing description says it was used as described in the following reference.
Cutter, L.S., G.A. Cutter, and M.L.C. San Diego‑McGlone. 1991. Simultaneous determination of inorganic arsenic and antimony species in natural waters using selective hydride generation with gas chromatography/photoionization detection. Anal. Chem. 63:1138‑1142. http://dx.doi.org/10.1021%2Fac00011a015