The development of an automated continuous measurement system for the monitoring of HCHO and CH3CHO in the atmosphere by using an annular diffusion scrubber coupled to HPLC

摘要: An automated continuous measurement system for the monitoring of formaldehyde (HCHO) and acetaldehyde (CH3CHO) in urban atmosphere was developed by using an annular diffusion scrubber conjunction with a high-performance liquid chromatograph (HPLC). With this technique, atmospheric HCHO CH3CHO were effectively collected which consists porous polytetrafluoroethylene (PTFE) tube disposed concentrically within Pyrex-glass scrubbing solution. 2,4-Dinitrophenylhydrazine (DNPH) selected as solution collecting CH3CHO, are derivatized to 2,4-dinitrophenylhydrazone-formaldehyde (DNPH-HCHO) 2,4-dinitrophenylhydrazone-acetaldehyde (DNPH-CH3CHO), respectively. aliquot sample automatically injected into HPLC equipped semi-micro ODS column UV-VIS detector separating determining DNPH-HCHO DNPH-CH3CHO. All operations sequenced programmable controller, measurements performed typical temporal resolution 1 h. The collection efficiencies about 97% 93%, respectively, at air flow rate 0.2 L/min. lower detection limits (3σ blank hydrazones) 0.05 ppbv 0.10 ppbv, case 12-L volume. Analytical response standard DNPH-CH3CHO during 10-day unchanged relative deviation (RSD) < 1.0%. Interferences from O3 NO2 insignificant method. Both measurements, concentrations well agreed those measured DNPH Silica cartridge