Validation of a gas chromatography/thermal conductivity detection method for the determination of the water content of oxygenated solvents.
A gas chromatographic (GC) method for the determination of the water content of acetone solutions containing methyl isobutyl ketone (MIBK) and other by-products of MIBK synthesis was developed and validated. Linearity is demonstrated (R2=0.9999) over a broad range of water concentrations in acetone ranging from 0.04 to 15.2% (w/w). The quantitation limit (QL) of this technique was found to be 0.346% (w/w) and the detection limit (DL) was estimated to be 13ppm. Validation of this analytical method's accuracy against a coulometric Karl Fischer titration (KFT) method showed excellent agreement between these two techniques. The GC/TCD method is accurate to within a relative error of 3.49% with respect to the KFT method for water concentration above the QL. However, the analysis of six samples below the QL showed an average relative error of 10.96%. Consequently, the KFT method is recommended for the moisture analysis of samples for water concentrations below 0.35% (w/w). Excellent precision is realized for water concentration above the QL (RSD<<0.8%). Good precision (RSD=1.1%) was obtained for the sample with the lowest water concentration investigated (0.04%, w/w). Repeatability, robustness and excellent specificity of this technique are demonstrated.
O'Keefe
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WK
The University of Waterloo, Department of Chemical Engineering, 200 University Avenue West, Waterloo, Ont. N2L 3G1, Canada.
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Rempel
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D002849:Chromatography, Gas / Q000379:methods*; D015203:Reproducibility of Results; D012997:Solvents / Q000032:analysis*; D013814:Thermal Conductivity; D014867:Water / Q000032:analysis*
D012997:Solvents; D014867:Water