气相色谱-负化学源质谱法测定蔬菜中17种拟除虫菊酯类农药残留量

建立了气相色谱-负化学源质谱检测蔬菜中17种拟除虫菊酯类农药残留量的方法。样品中的目标物经乙腈提取后,用乙二胺-N-丙基甲硅烷(PSA)和石墨化炭黑填料进行分散固相萃取净化,气相色谱-负化学源质谱选择离子监测模式测定,同位素内标法定量。在甜豌豆、绿花菜和大葱基质中均未见干扰所有农药测定的现象。17种拟除虫菊酯类农药的定量限均为0.02～5 μg/kg。在10、20、30和100 μg/kg等4个添加水平下,所有农药的回收率均为71.0%～139.0%,相对标准偏差≤12.8%。该方法可作为蔬菜中17种菊酯类农残检测的确证方法。     

Determination of pyrethroid metabolites in human urine by capillary gas chromatography-mass spectrometry

Summary An analytical method for the simultaneous determination of the pyrethroid metabolites cis and trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid, cis 3-(2,2-dibromovinyl)-2,2-dimethylcyclopropane carboxylic acid, 3-phenoxybenzoic acid and 4-fluoro-3-phenoxybenzoic acid in human urine samples is described. The urine is subjected to acid-induced hydrolysis followed by exhaustive solvent extraction, covering both conjugated and free acids, followed by a common derivatisation step yielding the corresponding methyl esters. Quantitation was by diastereomeric, capillary gas chromatography-mass spectrometry. It appears that 4-fluoro-3-phenoxybenzoic acid is a characteristic urinary marker for cyfluthrin exposure. The limits of determination are 0.5–1.0 g L^–1 urine depending on the metabolites concerned. The applicability of the method was tested on urine samples from pest control operators exposed occupationally to cypermethrin and cyfluthrin.     

Determination of 17 pyrethroid residues in troublesome matrices by gas chromatography/mass spectrometry with negative chemical ionization

An analytical method with the technique of QuEChERS (quick, easy, cheap, effective, rugged and safe) and gas chromatography (GC)/mass spectrometry (MS) in negative chemical ionization (NCI) has been developed for the determination of 17 pyrethroid pesticide residues in troublesome matrices, including garlic, onion, spring onion and chili. Pyrethroid residues were extracted with acidified acetonitrile saturated by hexane. After a modified QuEChERS clean-up step, the extract was analyzed by GC-NCI/MS in selected ion monitoring (SIM) mode. An isotope internal standard of trans-cypermethrin-D₆ was employed for quantitation. Chromatograms of pyrethroids obtained in all these matrices were relatively clean and without obvious interference. The limits of detection (LODs) ranged from 0.02 to 6 μg kg⁻¹ and recovery yields were from 54.0% to 129.8% at three spiked levels (20, 40 and 60 μg kg⁻¹ for chili, and 10, 20 and 30 μg kg⁻¹ for others) in four different matrices depending on the compounds determined. The relative standard deviations (RSDs) were all below 14%. Isomerization enhancement of pyrethroids in chili extract was observed and preliminarily explained, especially for acrinathrin and deltamethrin.     

液液萃取-高分辨气相色谱-高分辨双聚焦磁质谱法测定尿中羟基多环芳烃代谢物

建立了灵敏、准确的液液萃取-高分辨气相色谱-高分辨双聚焦磁质谱(LLC-HRGC-HRMS)同时测定人体尿样中8种多环芳烃(PAHs)代谢物的方法。将2 mL尿液与氘或¹³C标记的同位素内标物进行混合,在抗坏血酸的存在下酶解偶联目标物,再将游离化合物用甲苯-戊烷(1∶4, v/v)萃取后浓缩至近干,再用甲苯复溶,衍生后经HRGC-HRMS分离和测定。1-羟基萘在0.14～41.6μg/L、1-羟基菲在0.05～8.33μg/L、2-羟基菲在0.04～8.33μg/L、其他5种代谢产物在0.02～8.33μg/L范围内线性关系良好,相关系数>0.99,方法的检出限为0.006～0.042μg/L,平均回收率为81.4%～127.0%,日内和日间精密度分别为2.7%～6.9%和5.1%～10.9%(n=6)。应用该方法测定330份人群尿液样本,3-羟基■和6-羟基■未检出,其他6种PAHs代谢物检出率为100%。该方法灵敏、准确、稳定,适用于人尿中8种PAHs代谢物的定量分析。     

气相色谱-负化学离子源质谱法测定含硫蔬菜中残留的14种农药

建立了含硫蔬菜(大葱、大蒜、蒜薹及韭菜等)中14种农药残留的气相色谱-负化学离子源质谱(GC-NCI/MS)检测方法。样品先采用微波加热处理除去大部分的含硫干扰物,然后用乙腈均质提取,提取液用凝胶渗透色谱(GPC)和N-丙基乙二胺(PSA)固相萃取小柱净化后用GC-NCI/MS在选择离子监测模式下测定。在50 μg/kg加标水平下回收率为49.2%～113.1%,相对标准偏差为1.42%～8.70%,检出限(以3倍信噪比计)为0.5～10.0 μg/kg。方法的选择性好,抗干扰能力强,能消除复杂基质带来的干扰,适合于含硫蔬菜中农药残留的确证分析。     

气相色谱-负化学离子源质谱法检测胡萝卜中残留的环氟菌胺

建立了胡萝卜中环氟菌胺残留量的气相色谱-负化学离子源质谱(GC-NCI/MS)检测方法。用乙酸乙酯对胡萝卜中的环氟菌胺进行提取,并经固相萃取(SPE)净化后,由GC-NCI/MS在选择离子监测模式(SIM)下测定。该方法的准确度和精密度较高,在0.005,0.01,0.02,0.04 mg/kg 4个加标水平下,环氟菌胺的平均回收率均处于74.9%～96.4%之间,相对标准偏差(RSD)小于9.7%。在10～1000ng/mL范围内线性关系良好,检出限为0.001 mg/kg,定量限为0.005 mg/kg。该方法选择性好,抗干扰能力强,可作为胡萝卜中环氟菌胺残留检测的确证方法。     

GC-MS/NCI稳定同位素稀释技术检测动物源性食品中氯霉素的残留量

建立了一种用于各种动物源性食品中氯霉素残留量的气相色谱-负化学离子源质谱(GC-MS/NCI)检测方法。以氘代氯霉素(D5-CAP)为内标物,用乙酸乙酯对各类样品中的氯霉素进行提取,用正己烷和40 g/L NaCl溶液液液分配除脂肪,基质复杂的样品再用Oasi HLB固相萃取柱净化,经硅烷化衍生后由GC-MS/NCI在选择离子监测模式下进行测定。多数样品在0.2,0.5,1.0μg/kg3个添加水平下氯霉素的回收率处于87.8%和107.0%之间,相对标准偏差(RSD)不大于8.5%。方法在2.0~80.0μg/L范围内有良好的线性关系,基质复杂样品中氯霉素残留的检出限达到0.1μg/kg,基质简单样品的检测限可达0.05μg/kg。方法适合各种动物源性食品中氯霉素残留量的确证分析。     

微波辅助萃取-气相色谱-负化学电离/电子轰击电离-飞行时间质谱法测定烟草中农药残留

建立了微波辅助萃取结合气相色谱-飞行时间质谱(GC-TOF MS)技术在负化学电离(NCI)源和电子轰击电离(EI)源两种模式下测定烟草中24种农药残留的分析方法。烟叶样品于100℃下用二氯甲烷-正己烷(3:1, v/v)混合溶剂微波萃取10 min,萃取液经弗罗里硅土固相萃取柱净化后进行检测分析。在NCI源和EI源质谱模式下,24种农药的线性关系均良好(r²>0.99),相对标准偏差分别小于8.6%和9.1%,定量限分别为0.3~6.9 μg/kg和10.2~44.9 μg/kg,加标回收率分别为75.2%~94.8%和75.0%~95.1%。比较两种离子源模式下的色谱图和质谱图,NCI源模式较EI源模式的选择性好、灵敏度高、基质干扰小、图谱简单易于解析,检出限低一个数量级以上,在分析低含量、复杂基质的样品时更具优势。     

Measurement of equilin and estrone in human plasma by capillary gas chromatography-negative ion chemical ionization mass spectrometry

A procedure is described for the analysis of the estrogens equilin and estrone in human plasma following oral administration of conjugated estrogen preparations. After enzymatic hydrolysis of the sulfate conjugates, plasma proteins are precipitated with methanol and the estrogens extracted into ethyl acetate. Derivatization with the reagent flophemesylamine converts equilin and estrone into volatile pentafluorophenyldimethylsilyl ethers ideally suited to capillary gas chromatography-negative ion chemical ionization mass spectrometry. Using a 15 meter dimethyl silicone bonded phase fused silica capillary column separation of the estrone and equilin derivatives is achieved within 9 minutes. Selected ion monitoring of the intense negative molecular ions enables levels of 1 ng.ml^?1 to be measured with coefficients of variation of 9.3 % and 14.2 % for estrone and equilin respectively. Plasma levels of the compounds are reported in two male volunteers up to 24 hours after dosing with 5 milligrams of Premarin?. (? Ayerst Laboratories Inc., New York, USA.).     

Detection of β-blocking drugs in urine by capillary column gas chromatography-negative ion chemical ionization mass spectrometry

β-Blocking drugs present in commercial pharmaceutical products are determined in present urine of volunteers between 4 and 24 hours after the administration of a therapeutical dose. The drugs are extracted, hydrolysed, derivatized with pentafluoropropionic anhydride, and analyzed by capillary gas chromatography and electron capture detection. Metabolite identification and drug confirmation is by capillary gas chromatography–negative ion chemical ionization mass spectrometry (GC-NICIMS). This method is very specific and a sensitivity below 1 ng/ml is obtained.     

Quantitative analysis of memantine in human plasma by gas chromatography/negative ion chemical ionization/mass spectrometry

A sensitive and specific method for the determination of memantine in human plasma is presented. Memantine was extracted from plasma and derivatized to the pentafluorobenzoyl derivative in a one-step procedure avoiding any sample concentration steps. Amantadine was used as an internal standard. The compounds were measured by gas chromatography/negative ion chemical ionization mass spectrometry without any further processing. Using this detection mode, the fragment ions at m/z 353 and 325 were obtained at high relative abundance. Calibration graphs were linear over the range 0.117-30 ng ml(-1). At the limit of quantification (LOQ), the inter-assay precision was 2.00% and the intra-assay variability was 3.22%. The accuracy at the LOQ showed deviations of -1.42% (intra-assay) and -2.47% (inter-assay). The method is rugged, rapid and robust and was applied to the batch determination of memantine during pharmacokinetic profiling of the drug.     

Simultaneous analysis of carbohydrates,polyols and amines in urine samples using chemical ionization gas chromatography with tandem mass spectrometry

A simple method for the simultaneous derivatization of carbohydrates, polyols, amines and amino acids using hexamethyldisilazane and N,O‐bis(trimethylsilyl)trifluoroacetamide was developed. This method allows the direct derivatization of urine samples without sample pretreatment before derivatization. The method was successfully used for analysis of the selected metabolites in urine samples of healthy individuals and neonates suffering from galactosemia. The limits of detection by positive chemical ionization gas chromatography with tandem mass spectrometry analysis were in the range of 1.0 mgL^‐1 for mannitol to 4.7 mg/L for glucose.     

固相萃取-气相色谱-负化学源质谱法测定人血清中的多溴联苯醚

采用OasisHLB固相萃取柱萃取血清中的多溴联苯醚(PBDEs),经浓硫酸柱上除脂后,利用气相色谱-负化学源质谱法测定BDE-17、28、47、66、99、100、153、154、183和209共10种PBDEs组分。BDE-209的测定采用DB-5 ms色谱柱(15 m×0.25 mm×0.1 μm),其他组分采用VF-5 ms色谱柱(30 m×0.25 mm×0.25 μm)。对样品中蛋白质的去除溶剂和固相萃取条件(如洗脱溶剂及其用量)进行了优化。胎牛血清中的加标回收试验结果显示,各PBDEs单体相对于内标的平均回收率为78.5%～109.7%,日内测定的相对标准偏差(RSD)为0.3%～7.4%,日间测定的RSD为1.4%～14.1%。胎牛血清中三溴～七溴联苯醚的检出限(信噪比为3)为0.10～0.27 ng/L;定量限(信噪比为10)除了BDE-209为7.91 ng/L外,其他PBDEs为0.35～0.91 ng/L。采用本方法测定标准参考物质SRM1957和SRM1958,结果在参考值范围内。实验结果表明,本方法灵敏度高、准确度和精密度好,简便快速,溶剂消耗量少,适用于人体血清中三至十位溴取代联苯醚的测定。     

Determination of misoprostol free acid in human breast milk and serum by gas chromatography/negative ion chemical ionization tandem mass spectrometry

To study an expected transition of misoprostol from human blood into breast milk, a novel method for the determination of its active metabolite misoprostol acid (MPA) was developed. MPA was determined in serum and breast milk samples by an isotope dilution assay using gas chromatography/negative ion chemical ionization tandem mass spectrometry (GC/NICI-MS/MS). After addition of (15S)-15-methylprostaglandin E(2) (15-methyl-PGE(2)) as an internal standard, MPA was extracted from both matrices using a reversed-phase cartridge. The prostanoids were derivatized with O-2,3,4,5,6-pentafluorobenzylhydroxylamine hydrochloride (PFBHA) and 2,3,4,5,6-pentafluorobenzyl bromide (PFBB) to the pentafluorobenzyl oxime (PFBO)-pentafluorobenzyl ester (PFB) derivatives. The sample was subjected to thin-layer chromatography with ethyl acetate-hexane (1 : 1 (v/v)) as the developing solvent. The corresponding zone was extracted. After derivatization to the trimethylsilyl ether, MPA was determined by GC/NICI-MS/MS using the [molecule (M) - pentafluorobenzyl (PFB)](-) ([P](-)) ions as precursor in the negative ion chemical ionization mode. The product ions used for quantification were [P - 2TMSOH - C(6)F(5)CH(2)OH](-) (MPA) and [P - 2TMSOH - C(6)F(5)CH(2)OH - CO(2)](-)(15-methyl-PGE(2)), respectively. The limit of quantification for MPA was approximately 1 pg ml(-1) in breast milk and serum samples. The correlation coefficients of the calibration curves for MPA were r > 0.997 in the 0.5-2000 pg ml(-1) range for both tested matrices.     

气相色谱-负化学源-质谱法检测水中10种全氟羧酸化合物

建立了气相色谱-负化学源-质谱（GC-NCI-MS）检测水中10种全氟羧酸化合物的分析方法。使用硅烷衍生化试剂N-甲基-N-三甲基硅基三氟乙酰胺（MSTFA）对全氟羧酸化合物进行衍生化，水样经弱阴离子交换固相萃取柱净化富集后进样。实验优化了样品前处理、衍生化和仪器条件。结果表明，10种全氟羧酸化合物在0.1~10 mg/L范围内线性关系良好，相关系数为0.9956~0.9993；方法的检测限（LOD）和定量限（LOQ）分别为0.5~1.5 μg/L和1.5~4.5 μg/L。在空白水样中进行了3个添加水平的加标回收试验，10种全氟羧酸化合物的平均回收率为70.2%~112.6%，相对标准偏差（RSD）为2.1%~14.5%（n=6）。该法原理简单，灵敏度高，准确、精密，可实现水体中10种全氟羧酸化合物同时检测的要求。     

固相分散萃取与气相色谱-负化学离子源质谱联用法测定食品中三唑醇的残留量

建立了食品中三唑醇残留量的固相分散萃取-气相色谱-负化学离子源质谱联用检测方法。样品中三唑醇残留物由正己烷饱和的乙腈(含1%冰醋酸)提取,加入无水硫酸镁与无水醋酸钠振荡促使提取液分层后进行固相分散萃取净化,用气相色谱-负化学离子源质谱法进行测定与确证,外标法定量。方法具有良好的选择性和抗干扰能力,其检出限和定量限分别为0.001 mg/kg和0.003 mg/kg;线性范围为0.050～0.750 mg/L,相关系数为0.9947;在0.005,0.010,0.020 mg/kg共3个添加水平下的平均回收率为70%～110%,相对标准偏差不大于12.0%。该方法适合于多种食品中三唑醇残留量的确证分析。     

气相色谱-电子轰击电离/正化学电离质谱法测定白菜和苹果中3种有机锡类农药残留

分别采用电子轰击电离(EI)源和正化学电离(PCI)源两种离子源技术建立了气相色谱-质谱(GC-MS)同时测定白菜和苹果中苯丁锡、三苯锡和三环锡含量的方法,并对这两种方法进行了比较。样品经氢溴酸消解、丙酮-正己烷(1∶2,v/v)提取,四乙基硼化钠衍生后用Florisil固相萃取柱净化,分别在EI源和PCI源下以选择离子监测模式进行测定。结果表明,方法的检出限(S/N=3)分别为0.01~0.05 mg/kg(EI源)和0.01~0.02 mg/kg(PCI源),定量限(S/N=10)分别为0.03~0.16 mg/kg(EI源)和0.02~0.06 mg/kg(PCI源)。三苯锡、三环锡和苯丁锡分别在各自的线性范围内线性关系良好,相关系数(r~2)≥0.997。在50、100、200μg/kg 3个添加水平下,采用GC-EI/MS和GC-PCI/MS时,阴性样品中3种有机锡的平均回收率分别为59.24%~97.36%(苹果)、50.54%~94.54%(白菜)和65.38%~95.86%(苹果)、62.56%~90.44%(白菜),相对标准偏差(RSD)均不超过6.9%(n=6)。该方法简单、灵敏,PCI源的选择性优于EI源,两种方法可以相互结合提高检测结果的可靠性。     

气相色谱-负化学源质谱法测定禽蛋及蛋制品中氟虫腈及其代谢物

建立了气相色谱-负化学源质谱联用技术(GC-NCI-MS)测定禽蛋及蛋制品中氟虫腈及其3种代谢物残留量的方法。样品经乙腈提取,分散固相萃取技术QuEChERS净化,采用基质校正曲线外标法定量。在0.005~0.10mg/L范围内氟虫腈及其3种代谢物均呈现良好的线性关系,所有目标物的定量限均在0.025~0.10μg/kg范围内,均能满足国内外的限量要求。在0.1、2.0、4.0、20.0μg/kg 4个添加水平下,氟虫腈及其3种代谢物的平均回收率均处于87.0%~99.3%,RSD均≤12.7%,说明该法有较高的准确度和较好的稳定性。综上所述,该法灵敏度、准确度较高,精密度较好,可用于禽蛋及蛋制品中氟虫腈及其代谢物残留量的测定。     

气相色谱-负化学源质谱联用法测定水产品及食用油中氟乐灵的残留量

建立了一种可用于水产品及食用油中氟乐灵残留量分析的分散型固相萃取-气相色谱-负化学离子源质谱方法。水产品及食用油经乙腈提取,4 ℃冷藏后,采用分散型固相萃取法净化,由气相色谱-负化学离子源质谱选择离子监测技术进行测定与确证,同位素内标法定量。在1~40 μg/L范围内氟乐灵农药的线性关系良好;方法定量限（LOQ）为0.02 μg/kg;对鳗鱼、烤鳗、梭子蟹、小龙虾、猪油和橄榄油等6种复杂基质进行1.0、2.0和3.0 μg/kg等3个水平的添加回收试验,平均回收率均处于80%~100%之间,RSD≤10.3%;无干扰现象出现。该方法可作为水产品及食用油中氟乐灵残留检测的确证方法。     

同位素稀释高分辨气相色谱-高分辨质谱法测定土壤中痕量有机氯农药残留

建立了同位素稀释高分辨气相色谱-高分辨质谱测定土壤中痕量有机氯农药残留的分析方法。采用加速溶剂法萃取土壤样品,以正己烷/丙酮(体积比为1:1)为提取溶剂,提取液经过Florisil硅土固相萃取小柱净化后,采用高分辨DB-5MS毛细管色谱柱(30 m×0.25 mm×0.25 μm)分离,以保留时间和同位素特征离子丰度比定性,同位素峰面积比定量。实验结果表明,方法的回收率为77.3%～114.5%,相对标准偏差(RSD)≤10.81%（n=5）,检出限均小于0.04 pg/g。应用该方法检测某地区表层土壤中的有机氯农药,结果表明该方法适合测定环境土壤背景中痕量有机氯残留。