液相色谱-串联质谱法确证分析环境水样中痕量克百威

Identification of Trace Carbofuran in Environmental Water by Liquid Chromatography-Tandem Mass Spectrometry

采集水样后,立即按比例在每升水样中加入1.0mol·L-1硝酸溶液5mL,并于4℃温度下保存。取此水样9.0mL,加入甲酸-乙腈(1+99)混合液1.0mL,混匀,经0.2μm滤膜过滤。滤液按工作条件在Shim-pack XR-ODS II色谱柱上分离,以0.01%(体积分数)甲酸溶液-乙腈(3+7)混合液作流动相进行洗脱。洗脱液按选定条件泵入质谱离子源,在ESI+模式下,克百威的准分子离子为m/z 222.2[M+H]+,MS/MS裂解最强和次强碎片离子分别为m/z 123.0和m/z165.1,两者的峰强比为Im/z123.0∶Im/z165.1=100∶20。选择离子对m/z 222.2/123.0和m/z222.2/165.1作为定性分析离子对,并选择前者作为定量分析离子对。所提出的克百威的可能裂解途径采用Q Exactive高分辨质谱予以确认。在水样分析中,根据分析对象色谱分离的保留时间(2.67min)和裂解后的碎片离子及其峰的强度比,与克百威标准溶液的结果比较,即可判定水样中是否存在克百威。定量分析的结果表明:克百威质量浓度在0.05~10.0μg·L^(-1)内与对应的峰面积呈线性关系,其检出限(3S/N)为0.01μg·L^(-1)。用标准加入法进行回收试验,测得回收率在88.4%~96.5%之间。精密度试验的结果表明:其日内相对标准偏差(n=6)在0.90%~5.6%之间,日间相对标准偏差(n=6)在1.8%~7.3%之间。

To the water samples,after collection,5 mL of 1.0 mol·L-1 HNO3 solution was be added immediately for every liter of the sample,which should be then stored at 4℃.9.0 mL of the sample was taken and mixed with 1.0 mL of a mixed solution of formic acid and acetonitrile（1＋99）.The solution was filtered through0.2μm filtering membrane,and the filtrate was passed through Shim-pack XR-ODS II chromatographic column and eluted with the mobile phase of mixed solution of 0.01%（φ）formic acid solution and acetonitrile（3＋7）to separate carbofuran（CF）from other co-existing impurities.The eluate was pumped to the ionic source of MS/MS under optimized condition,and under the mode of ESI＋,the ion of quasi-molecule of CF,[M＋H]＋m/z 222.2,was fragmented to 2 main fragmented ions of m/z 123.0 and m/z 165.1.Ratio of peak strengths of these 2 ions was Im/z123.0∶Im/z165.1=100∶20.In latter testings,the ion-pairs of m/z222.2/123.0 and m/z222.2/165.1 were used for qualitative analysis,and the former ion pair was used for quantitative analysis.The proposed pathway of fragmentation of CF was confirmed by Q Exactive HRMS.In the analysis of water samples,based on the data of retention time（2.67 min）and fragmented ions,as well as the ratio of the peak strengths,as given by the analyte,and by comparing with the data given by standard solution of CF,the presence or not of CF in the sample could be concluded.As shown by results of quantitative testing,linear relationship was obtained between values of peak area and mass concentration of CF in the range of 0.05 to 10.0μg·L^（-1）,with detection limit（3 S/N）of 0.01μg·L^（-1）.Values of recovery found by standard addition method ranged from 88.4%to 96.5%,and values of inner-day RSDs（n=6）and inter-day RSDs（n=6）were in the ranges of 0.90%-5.6% and 1.8%-7.3%respectively.