We used gas chromatography to simultaneously quantify methanol, acetone, ethanol, and isopropanol (propan-2-ol) using propan-1-ol as the internal standard. Gas chromatography analysis was conducted using a ThermoScientific GC Trace 1300 system (Thermo Fisher Scientific, Waltham, MA) with a flame ionization detector (FID) and a headspace Thermoscientific TriPlus sampler. Chromatographic separation was achieved on a 30-m × 0.25-mm × 0.25-µm DB-WAX fused silica column (Agilent Technologies, Santa Clara, CA) using nitrogen as a carrier gas. SSL Injection port temperature was set to 200°C; the injection volume was 1 mL with split flow; and the oven temperature program was held at 50°C for a 7-minute run time. The FID detector was set at 250°C. Data were recorded and analyzed using Chromeleon 7.2 software (Thermo Fisher Scientific) using peak area ratios of analyte to internal standard with comparison to a 6-point standard curve for quantitative analysis of each analyte.
In a sealed vial, 200 µL internal standard (propan-1-ol) was added to the 10-µL sample and incubated 20 minutes at 80°C before injection. Routine quality-control samples consisted of Medidrug ALC VB 030 and 110 congener alcohols were analyzed before each sample analysis. The lower limit of quantification of isopropanol is 10 mg/L, and this method is linear until 750 mg/L.
In a sealed vial, 200 µL internal standard (propan-1-ol) was added to the 10-µL sample and incubated 20 minutes at 80°C before injection. Routine quality-control samples consisted of Medidrug ALC VB 030 and 110 congener alcohols were analyzed before each sample analysis. The lower limit of quantification of isopropanol is 10 mg/L, and this method is linear until 750 mg/L.