Vapor-phase analysis of isobutyl acetate, isopropyl acetate, n-propyl acetate and their respective alcohols using solid-phase microextraction-gas chromatography with a mass selective detector

A solid-phase microextraction (SPME)-GC-MS method for three esters and the corresponding alcohols was tested for responses in accuracy, within-run precision (repeatability), and between-run precision (reproducibility) due to individual operators, individual analysis days, and differing analyte concentrations. At 5 ppm (v/v) ppmv], three of the six analytes showed significant (p < 0.05) operator effects, while five of six analytes gave a significant effect due to the days of analysis. At 20 ppmv, five of the six analytes gave significant operator and daily effects. At 100 ppmv, all the analytes showed significant daily effects but no operator effects were observed. The repeatability was concentration dependent, with all six analytes combining for an average RSD of 12.1 +/- 6.1% at 1 ppmv, becoming most precise at 50 ppmv at 1.01 +/- 0.45%, then increasing at 100 ppmv to 4.12 +/- 1.88%. The contributors to error trended as: concentration > daily effects > operator.