An advanced technique for rapid and accurate monitoring of gaseous formaldehyde using large-volume injection interfaced with gas chromatograph/barrier discharge ionization detector (LVI/GC/BID)

Abstract

As a hazardous volatile organic compound (VOC), formaldehyde (FA) is found ubiquitously in both polluted and unpolluted environments. Hence, for the proper control of FA, techniques for rapid and precise quantitation of FA are in great demand. However, because of its low molecular weight and high reactivity, its quantitation generally requires complicated procedures (such as combination of sampling through 2,4-dinitrophenylhydrazine (DNPH) derivatization and detection through high-performance liquid chromatograph (HPLC)). Such an approach, despite proven reliability, is inefficient for fast tracking of FA level under dynamic conditions. To overcome such limitations and to facilitate the near real-time monitoring of gaseous FA, we developed an alternative detection method based on a gas chromatograph/barrier discharge ionization detector interfaced with a large-volume injection system (LVI/GC/BID). The reliability of lab-made gaseous standards of formaldehyde was investigated based on thermal cracking of paraformaldehyde. The developed LVI/GC/BID approach allowed the detection of gaseous FA with a method detection limit (MDL) of about 0.13 ng (0.21 ppm for 0.5 mL sample) over the linear dynamic range of 0.29-5300 ng with relative standard deviation (RSD) of 1.19% compared with the direct injection-based GC/BID MDL of 2.41 ng (6.56 ppm for 0.3 mL sample) and RSD of 3.35%.