A Flame Ionization Detector Highly Selective and Sensitive to Phosphorus—A Sodium Thermionic Detector

Abstract

Abstract A selective detector for use in a gas chromatography system for the detection of organophosphate pesticide residues in foods has been developed and investigated. The device consists of a conventional detector with a coat of a sodium salt fused onto the electrode. There are two requirements: sodium must be present and it must be heated. This sodium thermionic detector is highly selective in response to phosphorus in an organic compound. Other atoms generate some response also, but the relative sensitivity to phosphorus is so great that the sensitivity of the detector can be adjusted to measure essentially only phosphorus. The detector also responds selectively to halides but to a much lesser degree. The detector can detect and measure both organophosphate and chlorinated pesticide residues in a sample extract.