Semi-Quantitative Determination of Volatile Organic Compounds Detected in Air Using Solid-Phase Microextraction and...

Nontargeted air analysis using methods based on gas chromatography (GC) and mass spectrometry (MS) is very important for the discovery of new potentially dangerous volatile organic compounds (VOCs). Solid-phase microextraction (SPME) is one of the simplest and cost-efficient sampling techniques for screening VOCs in air, but the extraction effectiveness of detected compounds can substantially vary depending on their properties and affinity to the fiber coating. This study was aimed at the development of a novel method for semi-quantitative determination of VOCs identified in air samples using SPME and GC-MS. Extraction effectiveness was estimated from fiber coating-air distribution constants predicted using linear solvation energy relationship and numerical modeling with COMSOL Multiphysics. MS detector response factors were estimated using multiple regression obtained from experimental responses of 111 VOCs and SVOCs, their molecular weights, octanol-water partitioning coefficients, polar surface areas, and fractional ion abundances of base ions. Numerical modeling using COMSOL Multiphysics improved the accuracy for less volatile analytes with greater molecular weight, particularly at lower extraction times. For 12 of 14 tested analytes, recoveries from spiked nitrogen samples were in the range between 39% and 275%. The developed method was successfully applied for determining approximate concentrations of VOCs identified in samples of air, and for determination of approximate time-weighted average concentrations of VOCs. It can be recommended for the quick estimation of approximate concentrations of VOCs detected during nontargeted analysis when calibration standards are not available or when high accuracy is not needed.