高效液相色谱-串联质谱法测定食品中多杀菌素A和D的残留量

建立了食品中多杀菌素(spinosyn) A和D残留的液相色谱-串联质谱(HPLC-MS/MS)检测方法。甘蓝等食品样品经乙腈-水(50:50, v/v)提取、HLB固相萃取柱净化后,采用HPLC-MS/MS进行检测分析,利用外标法定量。质谱分析采用电喷雾电离,正离子扫描,多反应监测模式。结果表明,柱净化后无明显的基质效应,多杀菌素在1～20 μg/L内具有较好的线性关系,其相关系数可达0.9999;样品中添加1～10 μg/kg的多杀菌素,其回收率为76.2%～114.0%,相对标准偏差(n=10)小于10%;检出限(信噪比（S/N）=3): 多杀菌素A为0.2 μg/kg,多杀菌素D为0.5 μg/kg;定量限(S/N=10): 多杀菌素A为0.5 μg/kg,多杀菌素D为1.0 μg/kg。在最佳实验条件下,对来自福建厦门的969份食品样品进行了检测,其中15份样品检测结果呈阳性。实验结果表明,该方法提取效果好,具有良好的灵敏度、回收率和重复性。     

Comparison of different liquid chromatography methods for the determination of corticosteroids in biological matrices

Various extraction techniques can be combined with column liquid chromatography (LC) and ultraviolet (UV) or mass spectrometric (MS) detection for the determination of synthetic corticosteroids in biological matrices. Target analysis of low concentrations of 25 microg/kg of dexamethasone in feed can be performed by combining immunoaffinity chromatography (IAC) and LC with UV detection. A straightforward multi-analyte procedure is obtained by tandem solid-phase extraction (SPE) and subsequent LC-UV. However, the limits of detection for feed samples are then relatively poor, viz. 100 microg/kg. A multi-analyte method which meets modern demands of about 5 microg/kg detection limit requires one-step SPE combined with LC-MS analysis. As regards urine corticosteroids can be determined down to a level of 0.5 microg/l by either SPE-LC-MS- MS or SPE(IAC)-LC-MS.     

Simultaneous determination of 109 pesticides in unpolished rice by a combination of gel permeation chromatography and Florisil column purification, and gas chromatography/mass spectrometry

A multi-residue method is described for the simultaneous analysis of 109 pesticides with different properties in unpolished rice. The range covers organophosphorus, organochlorine, carbamate, and synthetic pyrethroid pesticides. The pesticides were extracted from the sample using ethyl acetate. Most higher molecular weight components such as lipids in the co-extractives were removed by gel permeation chromatography (GPC) with a Bio-bead SX-3 column. A Florisil column with ethyl acetate/hexane as the eluting solvents was used for further cleanup. The pesticides were finally simultaneously determined by gas chromatography/mass spectrometry (GC/MS) in selective ion monitoring (SIM) mode. The average recoveries for most pesticides (spiked level 0.02, 0.1 and 1 microg/g) ranged from 70% to 110%, the relative standard deviation (RSD) was below 20% in every case, and the limit of detection (LOD) varied from 1 to 20 ng/g.     

Determination of forchlorfenuron residues in watermelon by solid-phase extraction and high-performance liquid chromatography

A method using solid-phase extraction for cleanup, followed by high-performance liquid chromatography with ultraviolet detection (HPLC/UV), was developed for the determination of forchlorfenuron residues in watermelon. The pesticide is extracted from the sample with acidic acetonitrile, and the extract is loaded onto a primary-secondary amine (PSA) column. The pesticide is eluted with acetone and determined by HPLC/UV. The PSA column was found to provide effective cleanup, removing the greatest number of sample matrix interferences. The acetonitrile extraction followed by the PSA cleanup provided recoveries of >95%, coefficients of variation (precision) of <10%, and sensitivity of 0.005 mg/kg, in agreement with the directives for method validation in residue analysis. The proposed method was successfully used to determine forchlorfenuron residue levels and dissipation rates in watermelon grown in an experimental greenhouse in Beijing, People's Republic of China.     

Determination of lipid oxidation level in broiler meat by liquid chromatography

An assay was conducted for the determination of malondialdehyde (MDA) levels in broiler meat. The method involves extraction of tissues with trichloroacetic acid (TCA) and reaction of the TCA extract with 2,4-dinitrophenylhydrazine (DNPH). After separation of the MDA-DNPH complex using a solid-phase extraction C18 column, samples were eluted with 1 mL acetonitrile. Aliquots of 20 microL acetonitrile were analyzed by liquid chromatography on reversed-phase C18 column (3 microm) with UV detection. The products were eluted isocratically with the mobile phase containing acetonitrile-water-acetic acid (39 + 61 + 0.2, v/v/v). The retention time for MDA-DNPH was 6.5 min, and the detection limit was 3.5 microg/kg. Two extraction methods (cold and hot) were also used in the study. The results showed that hot extraction increased results about 55.8% and recovery from samples spiked with 116.6 microg/kg was lower (74.6%) in comparison with cold extraction (94.7%).     

Analysis of flame retardant additives in polymer fractions of waste of electric and electronic equipment (WEEE) by means of HPLC-UV/MS and GPC-HPLC-UV

An HPLC-UV/MS method has been developed to identify and quantify flame retardants in post-consumer plastics from waste of electric and electronic equipment (WEEE). Atmospheric pressure chemical ionisation spectra of 15 brominated and phosphate-based flame retardants were recorded and interpreted. The method was applied to detect flame retardant additives in polymer extracts obtained from pressurised liquid extraction of solid polymers. In addition, a screening method was developed for soluble styrene polymers to isolate a flame retardant fraction through the application of gel permeation chromatography (GPC). This fraction was transferred to an online-coupled HPLC column and detected by UV spectroscopy, which allowed a reliable qualitative and quantitative analysis of brominated flame retardants in the polymer solutions.     

Determination of malachite green and leucomalachite green in a variety of aquacultured products by liquid chromatography with tandem mass spectrometry detection

A liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed for determining the residues of malachite green (MG) and leucomalachite green (LMG) in a number of aquatic species. MG and its metabolite were extracted from homogenized tissues with a perchloric acid-acetonitrile solution; the extract was centrifuged; and an aliquot was taken, concentrated, and passed through a chemically bonded octadecyl C18 solid-phase extraction column. The compounds of interest were eluted with acetonitrile, and the eluate was evaporated to dryness. The residue was dissolved in acetonitrile and diluted with water in preparation for analysis by LC/MS/MS. MG and its metabolite were determined by reversed-phase LC using a Luna C18 column with an ammonium hydroxide-formic acid buffer in acetonitrile gradient and MS/MS detection using multiple reaction monitoring. Calibration curves were linear for all analyses between 5 and 500 pg injected for both analytes, with recoveries ranging from 81% for LMG to 98% for MG in salmon spiked at the 1 ng/g level. Detection limits of 0.1 ng/g for both MG and LMG were easily obtainable using the recommended method. The operational errors, interferences, and recoveries for spiked samples compared favorably with those obtained by established methodology. The recommended method is simple, rapid, and specific for monitoring residues of MG and LMG in a number of aquatic species.     

液相色谱/四极杆-飞行时间质谱法筛查奶酪中29种禁用和限用合成色素

建立了奶酪样品中29种禁用和限用合成色素的液相色谱/四极杆-飞行时间质谱(LC/Q-TOF MS)筛查方法。样品经正己烷-水(3:1, v/v)振荡提取,得到正己烷层、水层和残渣3部分。正己烷层经旋转蒸发浓缩后,用乙酸乙酯-环己烷(1:1, v/v)溶解,经过凝胶渗透色谱(GPC)净化去除油脂。水层经乙腈振荡提取,得到乙腈-水提取液。残渣经氨水-甲醇(1:99, v/v)溶液振荡提取,得到氨水-甲醇提取液。乙腈-水提取液和氨水-甲醇提取液不需净化直接分析。结果表明: 29种不同极性范围的合成色素化合物分别得到了有效的提取,提取回收率为70%～95%。而Q-TOF MS提供的精确质量数定性功能可以将不同种类的合成色素化合物筛查出来,各化合物与精确质量质谱库中化合物的匹配度为59.66～99.47。通过Target MS/MS扫描方式进行定量,得到8种苏丹类化合物的方法检出限为0.4～2.5 μg/kg, 21种水溶性合成色素及染料化合物的检出限为20～80 μg/kg。该方法对禁用和限用合成色素的筛查范围广泛,对含有蛋白质、脂肪等基质的食品具有较好的适用性。     

Sample preparation improvement in polycyclic aromatic hydrocarbons determination in olive oils by gel permeation chromatography and liquid chromatography with fluorescence detection

The determination of 15 polycyclic aromatic hydrocarbons (PAHs) in olive oil samples has been improved in order to obtain a fast methodology with a low limit of detection through the combination of liquid-liquid extraction with acetonitrile and preparative gel permeation chromatography (GPC) prior to the injection of purified extracts into a C18 column. Acetonitrile-water was used as the mobile phase with a gradient from 50 to 95%, w/w, acetonitrile in 30 min. The oven temperature was maintained at 15 degrees C, and fluorometric detection was made at a fixed excitation wavelength of 264 nm and variable, optimal emission wavelength for each analyte ranging from 352 nm for 11-H-benzo(b)fluorene to 500 nm for indeno(1,2,3-cd)pyrene. Recovery for all the compounds studied varied from 75 to 111%, and limit of detection values from 0.05 ng/g for benzo(k)fluoranthene to 0.48 ng/g for indeno(1,2,3-cd)pyrene, corresponding to 0.09 ng/g benzo(a)pyrene. Results were compared with those obtained by liquid-liquid extraction followed by a cleanup on silica and a direct GPC treatment of oil samples diluted in dichloromethane, 2 other methodologies that are appropriate for quantifying PAHs in olive oils. However, the proposed method improves the determination limits, reduces the time of analysis, and provides a highly stable baseline for sample chromatograms.     

高效液相色谱-线性离子阱三级质谱法检测花生中涕灭威及其代谢物涕灭威砜、涕灭威亚砜

建立了花生中涕灭威及其代谢物涕灭威砜、涕灭威亚砜的高效液相色谱-线性离子阱三级质谱分析方法。样品经环己烷饱和的乙腈提取,凝胶渗透色谱净化后,用高效液相色谱-线性离子阱三级质谱法对样品中的目标物进行定性确证和定量分析。在Capcell PAK CR色谱柱上以含5 mmol/L NH4Ac-HAc的乙腈为流动相进行梯度洗脱分离。采用电喷雾离子源正离子模式进行三级选择离子监测,以涕灭威-d3作为3个目标物的内标物。通过比较基质匹配曲线和纯溶剂标准曲线计算回收率评估基质效应。方法的线性范围为10～500 μg/L,检出限为4～5 μg/kg。涕灭威、涕灭威砜、涕灭威亚砜在3个加标水平(10、20、40 μg/kg)的回收率为81.5%～115%,相对标准偏差为6.35%～15.1%。应用该方法对花生样品进行了测定,结果令人满意。     

Confirmatory assay for the simultaneous detection of penicillins and cephalosporins in milk using liquid chromatography/tandem mass spectrometry

A high-performance liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for the detection of residues of penicillins and cephalosporins in milk has been developed. After a simple extraction with acetonitrile, the extract was directly injected into the LC/MS/MS system on a C(18) column. A gradient consisting of acetonitrile and water, each containing 0.1% formic acid, was applied. The abundant parent ions [M + H](+) produced by positive electrospray ionisation were selected for fragmentation with argon. For each compound at least one fragment was recorded with multiple reaction monitoring. The limits of detection ranged from 1.5 to 25 microg/kg and the limits of quantification ranged from 4 to 50 microg/kg. Recoveries were examined at three levels (MRL, 0.5 x MRL, 2 x MRL) and ranged from 57 to 88%. The coefficients of variation obtained for the repeatability experiments were in agreement with those specified by the Horwitz equation. Linearity was checked by injecting extracts of samples spiked with increasing amounts of the different standards ranging from 0 to 150 microg/kg. The advantage of this method over existing methods is the very simple sample pre-treatment which makes the method very suitable for routine analysis.     

Pyraflufen-ethyl residues in soil by solid phase extraction and high-performance liquid chromatography with UV detection.

Solid-phase extraction (SPE) procedure for cleanup followed by HPLC-UV method has been investigated for the determination of pyraflufen-ethyl residues in soil. The pesticide is extracted from the sample with acetone-water (80:20, v/v) and the extract is loaded onto an octadecyl (C(18)) column. The pesticide is eluted with acetonitrile and determined by HPLC with a UV detector. Using an acetone-water extraction followed by a C(18) cleanup, this method is characterized by recovery >90.1%, precision <5.8% RSD and sensitivity of 0.01 mg/kg. The proposed method has been successfully employed for the determination of the degradation dynamics of pyraflufen-ethyl in four agricultural soil samples under laboratory conditions.     

Determination of acysole in whole blood by high-performance liquid chromatography

A method is developed for the determination of a carbon monoxide antidote acysole in whole blood using hydrophilic interaction high-performance liquid chromatography with UV detection. Two methods were used for sample preparation: protein precipitation with acetonitrile and solid-phase extraction (SPE) with an acysole recovery of 95.8 and 89.8%, respectively. Chromatographic determination was performed in the isocratic mode on a Nucleodur HILIC column and with an acetonitrile: water 95: 5 mobile phase at 225 nm. The calibration graphs are linear in the concentration range 0.056–111.1 μg/mL. The limits of detection and determination of acysole were 0.050 and 0.120 μg/mL after protein precipitation with acetonitrile and 0.071 and 0.169 μg/mL with SPE, respectively.     

蔬菜和食用菌中氨基甲酸酯类农药残留检测技术

建立了丙酮和乙腈(体积比85:15)提取,凝胶渗透色谱(GPC)法和PSA(N-丙基乙二胺)固相萃取柱2种方法净化,超高效液相色谱-串联质谱（UPLC-MS/MS）同时检测菠菜、黄瓜、大葱、蘑菇、香菇、木耳、牛肝菌和胡萝卜中19种氨基甲酸酯类农药,同位素稀释法定量。实验结果表明,GPC法净化,回收率为70.1%～95.7%;PSA固相萃取柱净化,回收率为70.2%～94.9%。方法的检出限均为1×10-5 g/kg。各种NMCs在确定的添加范围内线性关系良好,线性相关系数r均＞0.99,所建立的检测方法实用、准确、灵敏度高。     

食用菌中多种氨基甲酸酯类农药残留的超高效液相色谱-串联质谱法测定研究

建立了同时测定食用菌中19种氨基甲酸酯类农药(NMCs)残留的超高效液相色谱-串联质谱法(UPLC-MS/MS)。通过丙酮和乙腈(85∶15,V/V)提取,GPC法和PSA固相萃取柱两种方法净化,UPLC-MS/MS同时测定蘑菇、香菇、木耳和牛肝菌中19种氨基甲酸酯类农药,同位素稀释法定量。以GPC法净化,回收率为74.0%～93.2%;以PSA固相萃取柱净化,回收率为70.2%～91.8%,两种方法的检出限均为0.01mg/kg。各种NMCs在确定的添加范围内线性关系良好,线性相关系数R均大于0.99。所建立的检测方法实用、准确、灵敏度高。     

Supercritical fluid extraction and quantitative determination of organophosphorus pesticide residues in wheat and maize using gas chromatography with flame photometric and mass spectrometric detection

An automated method using supercritical CO2 and clean-up by solid-phase extraction (SPE) using graphitized carbon black, has been developed for the quantitative determination of organophosphorus pesticide (OPP) residues in wheat and maize. Recoveries were as good as, or better than, those obtained using liquid extraction (LE) and gel permeation chromatography (GPC) for 10 OPP's spiked at levels equivalent to 0.05 and 0.50 microg/g. Lower limits of detection were possible using supercritical fluid extraction (SFE). Incurred residues were found in wheat and maize samples, and good agreement was obtained using SFE+SPE and LE+GPC. The SFE+SPE method required less analyst time and organic solvent, and hazardous waste was reduced.     

Determination of four nitroimidazoles in poultry and swine muscle and eggs by liquid chromatography/tandem mass spectrometry

A rapid method is presented for the determination of 4 nitroimidazoles in poultry and swine muscle and eggs by liquid chromatography/electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS). Samples were extracted with acetonitrile, then evaporated the organic phase. After filtration, the extract was directly injected into the LC/ESI-MS/MS system. The LC separation was made on a C8 column by applying a gradient composed of water and acetonitrile. Overall average recoveries ranged from 50-86% for egg, 66-115% for poultry muscle, and 79-111% for swine muscle. The decision limits ranged from 0.05-0.25 microg/kg for egg, 0.07-0.27 microg/kg for poultry muscle, and 0.07-0.26 microg/kg for swine muscle; and detection capabilities ranged from 0.51-0.68 microg/kg for egg, 0.41-0.75 microg/kg for poultry muscle, and 0.53-0.78 microg/kg for swine muscle.     

Quantitative analysis of phytoestrogens in kudzu-root, soy and spiked serum samples by high-pressure liquid chromatography

A sensitive and reliable HPLC method that allows simultaneous quantification of phytoestrogens extracted from kudzu-root and soy preparations, and serum samples has been developed. Kudzu-root and soy preparations were mixed with 5 microg flavone and 15 microg rutin (internal standards) and the phytoestrogens were extracted by using solid-phase (C18) extraction cartridges. Blank or spiked serum samples were extracted by using either C18 cartridges or trichloroacetic acid-methanol extraction. The extracts were analyzed by the HPLC equipped with a reverse-phase (250 x 4 mm, C18) column and UV, diode-array or MS detector. A linear gradient of acetic acid and acetonitrile provided excellent separation of glycoside and aglycone-phytoestrogens from kudzu root and soy preparations. The C18 cartridge extraction of serum yielded excellent recovery of both glycoside- and aglycone-phytoestrogens, while the trichloroacetic acid-methanol extraction yielded excellent recovery of glycoside but poor recovery of aglycone compounds. UV and MS detectors were suitable for phytoestrogen analysis in plant and serum samples, while the diode-array detector was suitable for generating the UV absorbance curve for phytoestrogens.     

Dispersive liquid-liquid microextraction based on solidification of floating organic droplet followed by high-performance liquid chromatography with ultraviolet detection and liquid chromatography-tandem mass spectrometry for the determination of triclosan and 2,4-dichlorophenol in water samples

A novel, simple and efficient dispersive liquid-liquid microextraction based on solidification of floating organic droplet (DLLME-SFO) technique coupled with high-performance liquid chromatography with ultraviolet detection (HPLC-UV) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for the determination of triclosan and its degradation product 2,4-dichlorophenol in real water samples. The extraction solvent used in this work is of low density, low volatility, low toxicity and proper melting point around room temperature. The extractant droplets can be collected easily by solidifying it at a lower temperature. Parameters that affect the extraction efficiency, including type and volume of extraction solvent and dispersive solvent, salt effect, pH and extraction time, were investigated and optimized in a 5 mL sample system by HPLC-UV. Under the optimum conditions (extraction solvent: 12 μL of 1-dodecanol; dispersive solvent: 300 of μL acetonitrile; sample pH: 6.0; extraction time: 1 min), the limits of detection (LODs) of the pretreatment method combined with LC-MS/MS were in the range of 0.002-0.02 μg L(-1) which are lower than or comparable with other reported approaches applied to the determination of the same compounds. Wide linearities, good precisions and satisfactory relative recoveries were also obtained. The proposed technique was successfully applied to determine triclosan and 2,4-dichlorophenol in real water samples.     

凝胶渗透色谱净化-高效液相色谱法测定油脂食品中的邻苯二甲酸酯类增塑剂

建立了油脂食品(方便面、油炸糕点、沙琪玛、食用油等)中5种主要邻苯二甲酸酯类增塑剂的凝胶渗透色谱（GPC）净化-高效液相色谱(HPLC)分析方法。食品样品用石油醚超声提取,经GPC净化后,采用反相HPLC进行分析。所用的分离柱为Labtech C18(250 mm×4.6 mm, 5 μm),以乙腈和水为流动相,梯度洗脱。方法的相关系数皆在0.997以上,目标物的检出限(信噪比为3计)为3.25～13.4 μg/L。在50 mg/L添加水平时,目标物的加标回收率为70.4%～113.6%,相对标准偏差为0.3%～5.8%(n=3)。该方法简便、快捷、实用,可用于油脂食品中邻苯二甲酸酯类增塑剂的分析测定。