Comparative Gas Chromatography of Halides Using Different Substituted Phenylboronic Acids as Derivatizing Reagents

The GC of halides (chloride, bromide and iodide) using phenylboronic acid (PBA), 4-bromophenylboronic acid (BPBA), 3, 5 bis (trifluoromethyl) phenylboronic acid (FPBA) and 2,4- dichlorophenylboronic acid (CPBA) as derivatizing reagents are compared. The reactions are carried out in the presence of mercuric salts. The detection systems used are FID and ECD. The thermal analysis of the compounds are studied prior to GC to get an indication of the likely operating temperatures. The unsubtituted phenylboronic acid show better volatility and FID response, but substituted phenylboronic acids exhibit better responses using ECD system. Finally FPBA is examined for the possible use in quantitative determination of chloride, bromide and iodide using solvent extraction procedure and ECD detection system. Detection limits for chloride, bromide and iodide are reported in the range of 0.29-0.35 pg.