环境空气中醛酮类化合物检测方法优化与初步应用

环境空气中的醛酮类化合物是当今大气环境科学领域的研究热点.醛酮类化合物因反应活性较高、性质不稳定，导致检测较为困难.为准确测定环境空气中的醛酮类化合物，针对环境空气中质量浓度较高或活性较强的18种醛酮类化合物的采样和分析方法进行研究，并采用优化的方法于2018年5月对北京市典型城区环境空气中的醛酮类化合物进行了检测.结果表明:①与手动采样器同时同地点采样数据相比，自行制作的醛酮类化合物自动采样器能够实现连续采样，数据基本一致（R2为0.999 7），其采样流速最大不超过0.8 L/min；醛酮类化合物采样管中杂质含量最高的乙醛为0.01 μg/管，小于我国HJ 683-2014《环境空气醛、酮类化合物的测定高效液相色谱法》标准限值（0.10 μg/管）.②采用所确定的二醛类化合物衍生化方法与质谱扫描条件可以成功检测乙二醛和甲基乙二醛两种二醛类化合物，建立了18种醛酮类化合物的标准曲线且标准曲线相关系数R2均大于0.995 0.③采用该优化方法得到北京市典型城区环境空气中18种醛酮类化合物质量浓度的日变化范围为17.73~88.42 μg/m3. 

Optimization and Preliminary Application of the Detection Method of Carbonyl Compounds in the Ambient Air

The ambient carbonyl compounds have become one of the research hotspots in atmospheric environment. Carbonyl compounds are difficult to detect because of their relatively higher reactivity and chemical instability. In order to detect ambient carbonyl and dicarbonyl compounds accurately, the sampling and analysis methods of 18 kinds of carbonyl and dicarbonyl compounds with relatively higher concentration or higher reactivity in ambient air were investigated and the optimized methods were applied to study the pollution characteristics of ambient carbonyl compounds in the typical urban area in Beijing in May 2018. The results showed that:(1) The automated multi-port sampler can collect sample continuously, under the same sampling conditions compared with the single-port sampler, the collected data had no obvious difference (R2=0.9997), and the maximum sampling flow rate was set to be 0.8 L/min. The highest impurity content in the sampling tube was 0.01 μg for one DNPH-cartridge, which was less than the standard limit of 0.10 μg for one DNPH-cartridge (HJ 683-2014 Ambient Air-Determination of Aldehyde and Ketone Compounds-High Performance Liquid Chromatography). (2) Two dicarbonyl compounds which are glyoxal and methyl glyoxal could be successfully detected by adopting the determined derivatization method of dicarbonyl compounds and the corresponding mass spectrometry scanning conditions; The standard curves of 18 kinds of carbonyl compounds were established and the correlation coefficients R2 of the standard curves were higher than 0.9950. (3) The mass concentrations of 18 carbonyl compounds in the ambient of the typical area in Beijing in this study period were 17.73-88.42 μg/m3.