ANALYSIS OF WATER IN LIQUID AND SOLID SAMPLES BY HEADSPACE GAS-CHROMATOGRAPHY .1. LIQUID AND SOLUBLE SOLID SAMPLES

Equilibrium headspace gas chromatography is applied for the analysis of water in liquid and solid samples which are first dissolved in a water miscible solvent. The preferred quantitation technique is the method of standard addition. A particular problem is the water blank, caused by the humidity of the enclosed air in the headspace vial and by the residual water content in the solvent. It has been found more convenient to include this water blank in the calculation rather than to avoid it by working under dry conditions. Both, precision and detection limit, depend on the reproducibility of this water blank. The combination of a hot wire detector with a fused silica capillary column was found superior to that with a packed column. Good agreement of the analytical result with the theoretical value was achieved with oxalic acid dihydrate as a test sample to prove the accuracy of the headspace approach. Practical applications are given for water analysis in a liquid solvent and in new and used engine oil. © 1990 Springer-Verlag.