基于现有标准不能有效分离丙烯醛和丙酮,优化了洗脱条件、色谱柱类型、流动相流量、检测波长等,以题示方法测定了乘用车车内空气中3种受控醛类物质的含量。用2,4-二硝基苯肼(DNPH)采样管在500 mL·min^-1流量下采集车内空气30 min。采样管两端分别连接5 mL容量瓶和装有5 mL乙腈(洗脱剂)的一次性注射器。洗脱采样管,使洗脱液的流向与采样时气流方向相反。洗脱液过0.45 μm滤膜,所得滤液经超声处理3 min后,用乙腈稀释至5 mL,于4℃冰箱中保存,7 d内用高效液相色谱法(HPLC)分析。以Agilent ZOBRAX Eclipse XDB-C₁₈色谱柱为固定相,以60%(体积分数)乙腈溶液为流动相在1.0 mL·min^-1流量下进行等度洗脱,分离得到的甲醛、乙醛和丙烯醛的衍生物用可变波长扫描紫外检测器(VWD)在360 nm处检测。结果显示:甲醛、乙醛、丙烯醛衍生物可在8 min内分离完全,且不受丙酮衍生物的干扰;标准曲线的线性范围均为0.015~0.75 mg·L^-1,检出限(3s)分别为0.002,0.003,0.004 mg·L^-1;按照试验方法测定0.075 mg·L^-1混合标准溶液,回收率为97.3%~105%,测定值的相对标准偏差(n=6)为1.9%~2.1%;方法用于实际样品的分析,仅检出了甲醛和乙醛,检出量均低于GB/T 27630-2011规定的限量。

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.