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Chinese EPA Method HJ 644 was released in 2013. It defines a procedure for the sampling and analysis of VOCs in ambient air, by using sampling onto sorbent tubes followed by TD–GC–MS analysis.

What’s involved in HJ 644?

HJ 644 was developed to assess a total of 35 non-polar VOCs, halogenated and aromatics in ambient air.

The method defines the sorbents to be used in the TD tube (Carbopack C, Carbopack B and Carboxen 1000 or equivalent). Samples are collected by pumping the atmosphere onto the sorbent tube, followed by TD–GC–MS analysis.

Complying with HJ 644

Tube-based sampling and trap-based focusing optimise the analysis of trace-level VOCs in ambient air, while multi-bed sorbents and backflush desorption of the tube and trap help to ensure high sensitivity for VOCs and SVOCs.

Markes’ TD100-xr and UNITY–ULTRA-xr thermal desorbers fully meet the requirements of HJ 644, complemented by a range of consumables and accessories.