New National Standard for Ambient Air Now in Effect! Wayeal's Canister Sampling–Preconcentration/GC Method for Determina

Preface

Sulfur compounds are key odor-causing and toxic/harmful pollutants in ambient air, mainly released via fugitive emissions from the chemical, petrochemical, wastewater treatment, waste disposal and pharmaceutical industries. Their extremely low odor threshold means even trace concentrations can cause nuisance odor complaints; some components are also toxic and corrosive. They affect regional air quality and public health, and are priority targets for odor pollution control and source apportionment.

HJ 1444-2026 "Ambient air — Determination of 10 sulfur compounds — Canister sampling–preconcentration/gas chromatography" officially took effect on August 1, 2026, replacing GB/T 14678-1993 which had been in force for over 30 years. It represents a comprehensive upgrade in method principle, technical scope and quality control.

This application note follows HJ 1444-2026 and uses the Wayeal GC6100 gas chromatograph with FPD detector, coupled with a Summa canister and atmospheric preconcentrator, for validation on standard samples.

Keywords: ambient air; sulfur compounds; gas chromatography; FPD detector; atmospheric preconcentrator.

1. Instrument Configuration

Table 1 Instrument configuration

A fully inert flow path plus a dedicated sulfur-compound column effectively prevents adsorption and loss of sulfur species.

2. Reagents and Auxiliary Equipment

Table 2 Concentrations of mixed 10-sulfur standard

2.1 Preparation of standard working gases

Connect the sampling canister to a gas dilution system. Dilute the mixed sulfur standard gas 500-fold with N2 to prepare working gas I, and 100-fold to prepare working gas II.

Working gas and calibration concentrations are listed in Table 3.

Table 3 Working gas and calibration concentrations (nmol/mol)

3. Results

3.1 Blank test

Figure 1 Blank chromatogram

The blank shows no significant impurity or interfering peaks; the system is clean with no adsorption carryover.

3.2 Typical standard chromatogram

Figure 2 Typical chromatogram of sulfur standard

1. Hydrogen sulfide 2. Carbonyl sulfide 3. Methanethiol 4. Ethanethiol 5. Dimethyl sulfide 6. Carbon disulfide 7. Ethyl methyl sulfide 8. Thiophene 9. Diethyl sulfide 10. Dimethyl disulfide

All 10 target compounds are well separated with symmetric peak shapes; readily adsorbing species such as hydrogen sulfide, methanethiol and ethanethiol elute normally.

3.3 Calibration curves

Inject 50/100/200 mL of working gas II and 100/200/400 mL of working gas I under the instrument reference conditions. Over this concentration range, the log of mole fraction is proportional to the log of peak area. Calibration curves were built with log(mole fraction, nmol/mol) on the x-axis and log(peak area) on the y-axis; all correlation coefficients R exceed 0.995.

Table 4 Calibration curve parameters for each target compound

Calibration curves for each target compound

3.4 Detection limit test

Detection limits were calculated from 7 replicate 50 mL injections of working gas II.

Figure 3 Detection-limit chromatogram

Peak responses are highly sensitive; detection limits are 0.01–0.02 nmol/mol, exceeding the standard requirements.

3.5 Repeatability test

Six replicate 100 mL injections of working gas II were run to evaluate low-concentration repeatability.

For the 0.5 nmol/mol standard over 6 injections: retention-time RSD < 0.6%, peak-area RSD < 1.5%, concentration RSD < 1.5%.

4. Conclusion

Results show that the GC6100 with FPD and atmospheric preconcentration system fully meets HJ 1444-2026 for the analysis of the 10 sulfur compounds (including hydrogen sulfide) in ambient air in terms of linear range, detection limit and precision; both detection limits and repeatability outperform the national standard requirements.