Comparative investigations on microextraction and conventional air sampling techniques: challenges and future directions

Abstract

Microextraction technique (e.g., solid phase microextraction, thin film microextraction, in-tube extraction) brings a revolutionary change in air sampling techniques over the recent few years. This advanced technique exhibits a high pollutant extraction rate, a low retention time, and a lower error margin compared to conventional air sampling techniques. The accuracy range of microextraction technique (MET) was recorded ~90-95% to isolate the volatile organic components, oxygenated and halogenated carbon particles from the air. However, the efficiency of MET increases additional >3-5% when employed by coupled with gas chromatography or gas chromatography-mass spectrometry. The conventional sampling techniques (e.g., bag sampling, grab sampling) on the other hand, displayed the accuracy of ~75- 80% which is ~20% lower than MET. The factors that potentially affect the performance of both conventional and MET were thoroughly investigated in this study. For instance, it was observed that the quality of needle coating used in MET significantly affects the pollutant trapping and at least ~5% of total performance cut off due to damaged and corroded coating. In addition, smart sensor-based air sampling techniques are also being investigated as this technique is a recent development in air quality monitoring. This fully automated state-of-the-art technology shows more than 98% accuracy with significantly high sensitivity and pollutant extraction rate. Finally, this investigation distinguishes the potential advantages, disadvantages, and challenges to increase accuracy between advanced and conventional sampling techniques, drawing attention to the urgent need to improve the performance of the air sampling techniques investigated in this study.