NEAR-INFRARED DETECTION OF FLOW-INJECTION ANALYSIS BY ACOUSTOOPTIC TUNABLE FILTER-BASED SPECTROPHOTOMETRY

The instrumentation development of a near-infrared (near-IR) spectroph otometer based on an acoustooptic tunable filter (AOTF) and its applic ation as a detector for now injection analysis (FIA) are reported, In addition to being compact and all solid state, this AOTF-based instrum ent is very sensitive, has high resolution, and can be rapidly scanned . The latter advantage make it uniquely suited as a detector for FIA, in that it can rapidly record the whole near-IR absorption spectrum of a mixture passing through the FIA now cell. Subsequent treatment of t he recorded spectra with multivariate calibration methods makes it pos sible to use the FIA, for the first time, for such applications as the simultaneous determination of trace amounts of water and benzene in e thanol, Because all organic compounds absorb light in the near-infrare d region, this AOTF-based near-IR detector can serve as a universal de tector for FIA; as a consequence, applications of the FIA techniques c an be expanded to other areas which are not possible otherwise.