Sin-QuEChERS Nano净化柱结合气相色谱-串联质谱法快速筛查石斛中84种农药残留

Rapid screening of 84 pesticide residues in dendrobium by Sin-QuEChERS Nano purification column with gas chromatography-tandem mass spectrometry

利用Sin-QuEChERS Nano净化柱结合气相色谱-串联质谱(GC-MS/MS)分析,建立了石斛基质中84种不同极性农药残留的快速筛查方法。比较了采用不同的提取溶剂(1%乙酸乙腈、丙酮)和不同的提取方式(加水浸泡和不加水浸泡)下目标物的提取效率。利用金钗石斛样品系统比较了Sin-QuEChERS Nano法与经典的基质固相分散法(dSPE)、固相萃取法(SPE)、QuEChERS法的净化效果及提取回收率,以及净化效果较好的Sin-QuEChERS Nano法与dSPE法基质效应的差异。目标物经DB-1701MS石英毛细管色谱柱(30 m×0.25 mm×0.25μm)程序升温分离,GC-MS/MS多反应监测(MRM)模式检测,基质匹配溶液外标法定量。通过GC-MS/MS检测方法对金钗石斛和铁皮石斛中的84种代表性农药进行了方法学验证。结果表明:各目标物在不同范围内呈良好的线性相关,相关系数(r^(2))均>0.990,方法的检出限(LOD,S/N=3)为1.5~5.8μg/kg,方法的定量限(LOQ,S/N=10)为5.0~15.0μg/kg。在两个水平下,目标农药的加标回收率为68.7%~116.2%,相对标准偏差(RSD,n=6)均低于15%。与其他经典的前处理方法相比,Sin-QuEChERS Nano法在净化效果方面表现更好,该法不仅可以有效去除色素、有机酸、碱性干扰物等物质,还可以节省样品制备时间,避免溶剂转移造成的损失,无需进一步涡旋或离心,是一种简单而有效的提取物纯化程序。该方法灵敏、快速、简便、可靠,有效地提高了石斛中农药快速筛查时的检测效率,具有较强的实际应用价值。此外,所开发的方法可以进一步扩展目标农药的类型,并可以用于检测其他更多食品及中药材中的农药残留。

A rapid screening method for 84 pesticide residues in dendrobium perfringens parent material with different polarities was developed using a Sin-QuEChERS Nano clean-up column combined with gas chromatography-tandem mass spectrometry(GC-MS/MS).The differences in extraction efficiency of the targets were compared with different extraction solvents(acetonitrile containing 1%acetic acid,acetone)and methods(immersion with or without water).The purification effect and extraction recoveries of Sin-QuEChERS Nano method and classical dispersive solid-phase extraction(dSPE),solid-phase extraction(SPE)and QuEChERS were systematically compared using Dendrobium nobile samples.The differences in matrix effects between the Sin-QuEChERS Nano method,which was more effective in purification,and the dSPE method were also analyzed.The purification effects of three commercially available Sin-QuEChERS Nano purification columns(simple matrix purification column,complex matrix purification column and herbal purification column)were compared.The applicability of the purification methods were also verified by using different parts of Dendrobium nobile samples(stems,leaves and flowers).From the results,it could be concluded that weighing 2.00 g and the samples in 5 mL of water for 20 min,followed by extraction with acetonitrile containing 1%acetic acid was more effective.The average extraction recovery of the target components by Sin-QuEChERS Nano purification method was 90.5%,which further identified Sin-QuEChERS Nano-Chinese medicine purification column as the preferred purification column for dendrobium purification.The target components were separated by a DB-1701MS quartz capillary column(30 m×0.25 mm×0.25μm)with programmed temperature rise,detected by multiple reaction monitoring(MRM)mode,and quantified by matrix-matched solution external standard method.The GC-MS/MS assay was used for the methodological validation of the 84 representative pesticides within Dendrobium officinale and Dendrobium nobile was carried out by GC-MS/MS detection method.The results indicated that the targets showed excellent linear correlation in different scopes with correlation coefficients(r^(2))>0.990.The limits of detection(LODs,S/N=3)of the method were 1.5 to 5.8μg/kg,and the limits of quantification(LOQs,S/N=10)ranged from 5.0 to 15.0μg/kg.The spiked recoveries of the target pesticides under different spiked levels were 68.7%-116.2%,and the relative standard deviations(RSDs,n=6)were less than 15%.Compared to other typical pretreatment methods,the Sin-QuEChERS Nano method provided better performance in terms of purification.The method not only effectively removed pigments,organic acids,and alkaline interferents,but also saved preparation time.Losses due to solvent transfer were also avoided and no further vortexing or centrifugation was required,making it a simplified and effective extraction and purification procedure.The method was sensitive,rapid,simple and reliable.It effectively improved the detection efficiency during the rapid screening of pesticides in dendrobium and presented a strong practical application value.In addition,the developed method could further expand the types of target pesticides and could be used to detect more pesticide residues in foods and Chinese herbal medicine.The established Sin-QuEChERS Nano method was used for the analysis of authentic samples.The applicability of the method was evaluated by analyzing a total of 80 samples collected from Anlong,Libo,Dushan,and Yanhe County in Guizhou Province.The types of samples included dendrobium maple,Dendrobium nobile(flowers,stems,leaves)and Dendrobium officinale(flowers,stems,leaves,powder,tablets).At least one pesticide residue was detected in 12 samples,with a detection rate of 15%.The five pesticides with higher detection rates and residues were chlorpyrifos(0.08-0.5 mg/kg),chlorothalonil(0.06-3.2 mg/kg),propanil zinc(0.03-0.15 mg/kg),methyl parathion(0.04-0.23 mg/kg)and cyhalothrin(0.10-2.68 mg/kg).Except for the pesticides in maximum residue limits(MRLs),the pesticide residues detected from dendrobium samples were below the limits set by Chinese national standard(GB 2763-2021)and local standard DBS 52/048-2020.