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An efficient and stability-indicating method has been developed and validated for the quantitative determination of tetrahydrofuran (THF), a hydrolytic degradation impurity, in Busulfan injectable pharmaceutical products by using gas chromatograph equipped with a liquid autosampler and a flame ionization detector. The chromatographic separation was performed on a fused silica capillary (Stabilwax; 60 m length × 0.32 mm i.d., 0.5 µm film thickness) column. The methodology was validated in accordance with regulatory guidelines. The proposed method was found to be specific, stable, precise, linear, accurate, robust, and rugged in the concentration range from 4 to 1,080 ppm for THF. The developed method was successfully applied to determine the THF content in Busulfan injectable pharmaceutical products.

An automated procedure is described for the rapid determination of the residual herbicide atrazine at ppb levels in soil-water extracts. The system consists of an autosampler connected to a C18 precolumn linked via a switching valve to a C18 analytical column and spectrophotometer. Peak height is superior to peak area for quantifying results with coefficients of variation of 0.48% and 0.89%, respectively, for 7.5 ng standard injections. Precolumn concentration eliminates the need for sample cleanup and achieves up to a 37% increase in peak height compared to an isocratic system. In a black earth soil, atrazine is identified as the principal phytotoxic constituent. The minimum detectable level is one-tenth the critical no-effect threshold for wheat. The method is well suited for predicting possible atrazine injury to susceptible crops and the measurement of other nonpolar analytes in aqueous solution.

An analytical method is developed to quantitatively determine glucosamine, galactosamine, and mannosamine in dried-and-ground burley and flue-cured tobaccos. Extraction is shown to be quantitative in the range of 0.01 to 2.0% (w/w). The extraction procedure consists of shaking one g of sample with 50 mL of deionized water adjusted to pH 7 for 30 min. This extract is filtered directly into an autosampler vial. An autosampler is programmed to withdraw two different aliquots: one with o-phthalaldehyde (OPA) derivatizing solution and the second one from the tobacco extract. The derivatization reaction occurs in the tubing connecting the autosampler and the chromatographic column. The OPA derivatives of these aminosugars are then detected with a fluorimetric detector, and their simultaneous analysis is performed with an external standard. This method is shown to be selective, accurate, and precise.