Determination of Formaldehyde, Acetaldehyde and Acrolein in Air of Passenger Car by High Performance Liquid Chromatography

Based on the fact that the existing standards cannot effectively separate acrolein and acetone, the elution conditions, chromatographic column type, flow rate of mobile phase and detection wavelength were optimized, and the 3 controlled aldehydes in the air of the passenger car were determined by the title method. A sampling tube loaded with 2,4-dinitrophenylhydrazine (DNPH) was used for collecting the air of the car for 30 min at flow rate of 500 mL·min^-1. The two ends of the sampling tube were respectively connected to a 5 mL-volumetric flask and a disposable syringe filled with 5 mL of acetonitrile (elution solvent). The sampling tube was eluted, and the flow direction of the eluate was opposite to that of the air flow during sampling. After the eluate was passed through a 0.45 μm filter membrane, the obtained filtrate was ultrasonicated for 3 min, diluted with acetonitrile to 5 mL, stored in the refrigerator at 4 ℃, and analyzed by high performance liquid chromatography (HPLC) within 7 d. Agilent ZOBRAX Eclipse XDB-C₁₈ chromatographic column was used as the stationary phase, and 60% (volume fraction) acetonitrile solution was used as the mobile phase. Isocratic elution was carried out at flow rate of 1.0 mL·min^-1, and derivatives of formaldehyde, acetaldehyde and acrolein separated were detected with VWD at 360 nm. As found by results, derivatives of formaldehyde, acetaldehyde and acrolein could be completely separated within 8 min without interference from acetone derivatives. Linear ranges of standard curves were found in the range of 0.015-0.75 mg·L^-1, with detection limits (3s) of 0.002, 0.003, 0.004 mg·L^-1. The mixed standard solution of 0.075 mg·L^-1 was determined by the above method, and the recoveries were 97.3%-105%, with RSDs (n=6) of the determined values in the range of 1.9%-2.1%. The proposed method was applied to analysis of actual samples, and only formaldehyde and acetaldehyde were detected, with the detected amounts lower than the limits specified in GB/T 27630-2011.