Chinese EPA Method HJ 759 was issued in 2015. It specifies a procedure for canister sampling and GC–MS detection for the determination of VOCs in ambient air.
What’s involved in HJ 759?
HJ 759 was developed to determine 67 VOCs with volatilities ranging from propylene to naphthalene, including the ‘air toxics’ listed in US EPA Method TO-15.
Ambient air samples are collected in inert stainless steel canisters, followed by concentration on a focusing trap, and thermal desorption to inject the compounds onto the GC–MS.
Complying with HJ 759
Functions such as automatic quantitative sampling and injection of standard gases or internal standards are required by the method.
Markes’ UNITY–CIA Advantage-xr systems incorporating a Kori-xr water condenser offer full compliance with the requirements of HJ 759, in the same way as they already comply with US EPA Method TO-15. Electronic control of the split, and optional small-volume loop sampling, enhance the ability to analyse high-concentration samples. In addition, Kori-xr allows samples at 100% relative humidity to be analysed without risking loss of the most volatile species.