气相色谱-质谱法测定含脂羊毛中有机氯和拟除虫菊酯杀虫剂残留量

采用气相色沓质谱联用法测定含脂羊毛中有机氯和拟除虫菊酯杀虫剂的残留量.样品经二氧化碳超临界萃取仪萃取后,所得提取液先后经过自动凝胶渗透色谱仪和Bond Elut Si固相萃取柱净化浓缩,所得洗脱液经氮气吹干后定容至1.0 mL,于气相色谱和气相色谱-质谱分析仪测定,外标法定量.11种有机氯和5种拟除虫菊酯杀虫剂的工作曲线呈较好线性关系,检出限(3S/N)在0.022～0.32 mg·kg-1之间,测定下限(10S/N)在0.073～1.07 mg·kg-1之间.在3个标准加入水平下进行了回收率和精密度试验,所得回收率在74.8%～135.2%之间,相对标准偏差(n=6)小于10%.     

快速溶剂萃取-气相色谱法同时测定含脂羊毛中的28种有机氯拟除虫菊酯杀虫剂的残留量

建立了快速溶剂萃取-气相色谱法同时测定含脂羊毛中28种有机氯、拟除虫菊酯杀虫剂残留量的方法。在80 ℃、10.34 MPa条件下用正己烷饱和的乙腈快速提取样品,提取物经冷冻除脂、浓缩、固相萃取净化处理后直接用气相色谱分析。结果表明:16种有机氯杀虫剂在0.005～1.0 mg/L范围内,9种拟除虫菊酯杀虫剂及三氯杀螨醇、三氯杀螨砜在0.01～2.0 mg/L范围内,氟氯苯菊酯在0.02～4.0 mg/L范围内,其峰面积与质量浓度呈良好的线性关系。28种有机氯、拟除虫菊酯杀虫剂的平均回收率为67.2%～107.7%,相对标准偏差为2.6%～29.0%。结果表明：该方法具有操作简便、快速方便、灵敏度高等特点,完全可满足含脂羊毛中28种有机氯拟除虫菊酯杀虫剂残留量初筛检测的要求。     

基质固相萃取-气相色谱电子捕获检测器同时测定大米中12种有机氯农药残留量

建立了大米中12种有机氯农药气相色谱-电子捕获检测器检测方法.采用基质固相分散(Matrix Solid Phase Disperse, MSPD)技术进行样品前处理, 用气相色谱-电子捕获检测器进行快速定性定量分析.基质固相分散集提取、过滤、净化于一步完成, 避免了样品均化、转溶、乳化、浓缩造成的待测农药组分的损失, 大大提高了方法的准确度和精密度.12种有机氯农药的添加回收率在83%～103%之间,相对标准偏差为2.2%～19%.     

固相萃取气相色谱法检测烟叶中有机磷类杀虫剂残留

用固相萃取气相色谱法检测烟叶中的有机磷类杀虫剂多残留。烟叶样品经乙腈超声提取、硅胶固相萃取柱净化后,用气相色谱火焰光度检测器检测。13种有机磷杀虫剂的回收率分别为79.32%～98.37%,相对标准偏差分别为2.48%～4.76%,检出限为0.02～0.08μg/g。该方法灵敏、准确,适用于烟叶中有机磷杀虫剂多残留分析。     

固相萃取-气相色谱-质谱法测定运动员血清中有机氯

建立了一种利用Captiva Emr-lipid固相萃取结合气相色谱-质谱联用仪(GC-MS)同时检测运动员血清中21种有机氯农药残留的方法。血清样品经1%酸化乙腈去蛋白后,Captiva Emr-lipid固相萃取柱净化,GC-MS测定,选择离子监测模式(SIM)监测,内标法定量。结果表明,21种有机氯农药在2～300 ng/mL的范围内,线性良好,相关系数均大于0.99。在5,10,20,50 ng/mL的添加水平下,方法准确度为79%～115%,相对标准偏差(RSD)20%。Captiva Emr-lipid固相萃取柱可以有效净化血清样品,适用于血清中多种有机氯农药的定性和定量分析。     

气相色谱-串联质谱法同时测定白芍中10种有机磷农药残留

建立了同时测定中药白芍中10种有机磷农药残留含量的气相色谱–串联质谱方法。样品用乙腈超声提取,提取液经凝胶渗透色谱净化后,以VF–5毛细管色谱柱(30 mm×0.25 mm,0.25μm)分离,串联四极杆质谱仪为检测器进行定性、定量分析。10种有机磷农药残留的检出限为0.02～4.0 mg/kg,实际样品的加标回收率为75%～105%,相对标准偏差为4%～10%。该方法能够满足白芍中有机磷农药残留的定性、定量检测要求。     

高效液相色谱法同时测定含脂羊毛中残留的除虫脲和杀铃脲

建立了同时测定含脂羊毛中除虫脲和杀铃脲的反相高效液相色谱方法。样品用正己烷-乙醚混合溶剂提取,经凝胶渗透色谱柱和固相萃取柱净化后,采用反相高效液相色谱-二极管阵列检测器检测,外标法定量。除虫脲和杀铃脲分别在0.41～41 mg/L和0.38～38 mg/L范围内线性关系良好,相关系数分别为0.9996和0.9999。最低检出限:除虫脲为0.22 mg/kg,杀铃脲为0.18 mg/kg;最低定量限:除虫脲为0.73 mg/kg,杀铃脲为0.60 mg/kg。在添加水平为0.76～10.25 mg/kg的除虫脲和杀铃脲时,平均加标回收率为86.3%～96.7%,相对标准偏差为4.2%～8.7%。该方法杂质干扰小、回收率高、重现性好,能够对含脂羊毛中除虫脲和杀铃脲残留量进行准确的定性定量分析。     

同位素稀释-高分辨气相色谱-高分辨质谱法测定土壤和沉积物中27种有机氯农药

采用同位素稀释-高分辨气相色谱-高分辨质谱法测定土壤、沉积物中的27种有机氯农药。以二氯甲烷-丙酮(1+1)混合液为提取溶剂对样品进行加速溶剂萃取,萃取液分别经凝胶渗透色谱柱和硅胶、氧化铝混合柱净化后,在DB-5MS非极性色谱柱上分离,以同位素稀释法进行定性定量分析。检出限(3s)不大于0.11μg·L-1,加标回收率在65.1%~102%之间,测定值的相对标准偏差(n=5)不大于7.0%。     

超声波溶剂提取-气相色谱法测定烟草及烟草制品中19种有机氯农药残留

建立了超声波溶剂提取-气相色谱法同时测定烟草及其制品中19种有机氯农药残留。样品采用正己烷-丙酮超声提取,经Florisil固相萃取柱净化后,采用气相色谱-电子捕获检测法(GC-ECD)进行检测。结果发现,19种有机氯农药加标回收率均在72%以上,相对标准偏差(RSD)在0.1%～9.0%,能满足当前烟草中有机氯农药残留的同时快速检测要求。     

油品族组成的详细分析和燃油中芳烃的分析

用毛细管液相色谱-毛细管气相色谱联用方法详细分析了航空煤油、各种柴油、润滑油、抽出油和塔底油的族组成。在毛细管液相色谱上分离得到的单环、双环、三环、四环和稠环芳烃族,经过多位存储接口后,顺序进入毛细管气相色谱,通过毛细管气相色谱对每个族组分作详细分析及定量。用单检测器的二维毛细管气相色谱切割-反吹方法定性定量分析汽油、航空煤油中的各种芳烃,从第一维柱流出的组分和第二维柱流出的组分都先后进入同一氢火焰离子化检测器中,因此能用质量校正响应因子归一化方法准确定量分析而不需要标准样。用上述技术分析实际样品,证明了     

高效液相色谱法测定含脂羊毛中灭蝇胺和环虫腈

建立了高效液相色谱法(HPLC)测定含脂羊毛中的灭蝇胺和环虫腈的方法及HPLC-MS/MS确证方法。样品用80mL1%三氯乙酸溶液超声提取,MCX柱净化,Hypersil NH2色谱柱分离,水-乙腈为流动相梯度洗脱,214nm检测,HPLC-MS/MS确证。在正离子电喷雾电离(ESI+)模式下,环虫腈[M+H]+及2个主要的特征离子分别为m/z191.0,150.0和163.0;灭蝇胺[M+H]+及2个主要的特征离子分别为m/z167.0,85.0和125.0。在0.05～5.0mg/L范围内,灭蝇胺和环虫腈均有良好的线性关系,相关系数均为0.9999。本方法的检出限灭蝇胺为0.02mg/kg,环虫腈为0.01mg/kg。方法的平均加标回收率:灭蝇胺为95.0%～99.9%,环虫腈为83.6%～92.2%。     

快速溶剂萃取-高效液相色谱法测定含脂羊毛中残留的除虫脲和杀铃脲

建立了快速溶剂萃取-高效液相色谱(ASE-HPLC)测定含脂羊毛中除虫脲、杀铃脲残留量的方法。以正己烷饱和的乙腈为萃取剂,在80 ℃、10.34 MPa条件下用快速溶剂萃取仪提取样品中的目标物,提取液经冷冻除脂、浓缩及Waters Plus Silica柱净化后,采用Waters Atlants dC18色谱柱分离,以乙腈和水为流动相进行梯度洗脱,二极管阵列检测器于254 nm处检测。结果表明,在0.1～10.0 mg/L范围内,除虫脲、杀铃脲的峰面积与其质量浓度的线性关系良好,相关系数均大于0.9999,定量检出限(S/N≥10)分别为0.05,0.04 mg/kg。该方法具有操作简便、快速、灵敏度高等特点,完全能满足含脂羊毛中除虫脲、杀铃脲残留初筛检测的要求。     

Effect of the carbon dioxide modifier on the lipid composition of wool wax extracted from raw wool

Wool wax or lanolin is a unique substance secreted by sheep and forms a natural protective coating on wool fibres. It is widely used in pharmaceutical and cosmetic formulations. However, different systems of wool wax recovery from scouring liquour provide a dark impurified greasy product. This product has a lipid composition that differs from the wool wax present on wool fibres. The wool wax extraction method from raw wool with pressurised CO₂ and different modifiers at constant pressure and temperature was studied. Thin-layer chromatography coupled to an automated flame ionisation detection system (TLC/FID) was used to analyse the different lipid classes present in the collected extracts. Moreover, a detailed structural comparison of the cholesteryl esters and hydroxycholesteryl esters was carried out by means of sub-ambient pressure chromatography mass spectrometry in the electron impact and in the ammonia positive chemical ionisation modes. For comparison, qualitative and quantitative analyses of the lanolin extracted in Soxhlet with dichloromethane and commercial cosmetic lanolin were carried out. Differences in the quantity of wool wax extraction and in the lipid composition of different wool wax extracts were detected by changing the modifier polarity.     

Determination of Volatile Nitrosamines in Latex Products by HS-SPME–GC–MS

Nitrosamines which have been detected in various latex products are carcinogens. The method for determination of volatile nitrosamines in latex products was developed using a combination of headspace solid phase micro-extraction (HS-SPME) and gas chromatography–mass spectrometry (GC–MS). A carboxen/polydimethylsiloxane (CAR/PDMS) fiber was used for HS-SPME involving the following variables: (1) agitation conditions, (2) extraction temperature (3) extraction time, and (4) salt concentration. The instrument performances of three detection systems including GC combined thermal energy analyzer, nitrogen chemiluminescence detector and MS were evaluated. The agitation conditions including magnetic stirring and ultrasonication were investigated by the comparison of extraction efficiency of HS-SPME for nitrosamines. Obtained optimal detection conditions of nitrosamines were HS-SPME at 45 °C for 60 min assisted with magnetic stirring and saturated NaCl followed by GC–MS. To evaluate this method performance, the commercial products including eleven latex products (gloves, balloons and condoms) and four liquid silicone nipples were analyzed with the method. The results revealed that the method is suitable for simple and effective determination of nitrosamines in latex products. The advantage of this HS-SPME–GC–MS method is simple treatment, fast analysis, adequate sensitivity and without organic solvent.

     

Dispersive liquid–liquid microextraction using extraction solvent lighter than water

For the first time a dispersive liquid–liquid microextraction method on the basis of an extraction solvent lighter than water was presented in this study. Three organophosphorus pesticides (OPPs) were selected as model compounds and the proposed method was carried out for their preconcentration from water samples. In this extraction method, a mixture of cyclohexane (extraction solvent) and acetone (disperser) is rapidly injected into the aqueous sample in a special vessel (see experimental section) by syringe. Thereby, a cloudy solution is formed. In this step, the OPPs are extracted into the fine droplets of cyclohexane dispersed into aqueous phase. After centrifuging the fine droplets of cyclohexane are collected on the upper of the extraction vessel. The upper phase (0.40 μL) is injected into the gas chromatograph (GC) for separation. Analytes were detected by a flame ionization detector (FID) (for high concentrations) or MS (for low concentrations). Some important parameters, such as the kind of extraction and dispersive solvents and volume of them, extraction time, temperature, and salt amount were investigated. Under the optimum conditions, the enrichment factors (EFs) ranged from 100 to 150 and extraction recoveries varied between 68 and 105%, both of which are relatively high over those of published methods. The linear ranges were wide (10–100 000 μg/L for GC‐FID and 0.01–1 μg/L for GC‐MS) and LODs were low (3–4 μg/L for GC‐FID and 0.003 μg/L for GC‐MS). The RSDs for 100.0 μg/L of each OPP in water were in the range of 5.3–7.8% (n = 5).     

Analysis of pesticides residues in fresh produce using buffered acetonitrile extraction and aminopropyl cleanup with gas chromatography/triple quadrupole mass spectrometry, liquid chromatography/triple quadrupole mass spectrometry, gas chromatography/ion trap detector mass spectrometry, and GC with a halogen-specific detector

A rapid and inexpensive multiresidue method for determining pesticides in fruits and vegetables is presented. Extraction of a 15 g sample with 15 mL acetonitrile was followed by buffering with magnesium sulfate, sodium chloride, sodium citrate dihydrate, and disodium citrate. Acidification with formic acid prior to dispersive cleanup with aminopropyl sorbent and magnesium sulfate was used to stabilize base-sensitive pesticides such as chlorothalonil. Extracts were concentrated to 2 g/mL. Analyses were conducted by GC/ion trap detector MS, GC-halogen-specific detector, and LC/triple quadrupole MS. Accuracy and repeatability for 166 compounds in tomato, potato, and cabbage were 70-120% and <20% CV in 85% of the compounds, respectively. Reproducibility over a 4 month period in multiple commodities and analytical conditions was 62-124%, with CVs better than 30% for 91% of the compounds. Supply cost/sample was reduced 66%, and time to extract a batch of 24 samples was reduced by half compared to the prior method that used a 50 g sample, 100 mL acetonitrile, multiple SPE columns, and additional instrumentation. Additional extraction studies were conducted in tomatoes, oranges, and green beans at 4 g/mL using a GC/MS triple quadrupole system with a programmable temperature vaporization inlet. Recoveries of 70-120% were achieved in 93% of all compounds in green beans, 95% in tomatoes, and 97% in oranges.     

Feed additives in animal nutrition: Quantification of a new adrenergic drug by hyphenated techniques

Zilpaterol, (±)‐trans‐4,5,6,7‐tetrahydro‐7‐hydroxy‐6‐(isopropylamino) imidazo [4,5,1‐jk]‐[1]benzazepin‐2(1H)‐one, is an adrenergic agonist drug licensed in Mexico and South Africa as feed additive for cattle at slaughter age. In contrast, the EU legislative framework prohibits the use of beta‐agonists as growth promoters to produce lean meat. In this study, the compound was quantified as its TMS derivative both by gas chromatography‐mass spectrometry (GC‐MS) with a quadrupole detector (QUADR) and by GC‐MS/MS with an ion trap detector (ITD), in Electron Impact (EI) ionization. Subsequently, an extraction and clean‐up procedure for the identification of Zilpaterol in commercial feeds was set up. Different extraction solvents and matrices were considered for their influence on Zilpaterol yield. The analytical method led to good recoveries and limits of detection and quantification in feeds well below the 5–20 μg/g dose proposed for animal nutrition.     

Trace determination of alpha- and beta-endosulfan and three metabolites in human serum by gas chromatography electron capture detection and gas chromatography tandem mass spectrometry

Endosufan, alpha and beta, and three conversion products, sulphate, ether and lactone, were simultaneously determined in human serum by means of an analytical procedure which combines extraction with organic solvents, clean-up with H(2)SO(4) and by liquid column chromatography, and detection by gas chromatography (GC) using electron capture detection (ECD) and tandem mass spectrometry (MS/MS). The procedure was validated and the values of some merit figures, such as linear range, detection and quantitation limits, accuracy, precision and recovery, obtained with the GC/ECD and the GC/MS/MS methods, were compared. The lower limits of detection in GC/ECD and GC/MS/MS were 0.03 and 0.05 microg I(-1), respectively. The recovery of the pesticides at the 20 microg I(-1) concentration level was 60-65%, with the exception of endosufan alpha. Recovery studies at higher levels (100 and 200 microg I(-1)) were independent of pesticide concentration in serum samples. The application of the proposed analytical methodology to the determination of endosulfans and their metabolites in real samples was tested by analyzing serum samples from a population living in agricultural areas of Almeria (Spain). The results show the advantage of MS/MS over the ECD detector in the analysis of serum samples where matrix interferences can be confused with target pesticides.