固相萃取液相色谱-二极管阵列检测器测定猪肾中三聚氰胺

建立了液相色谱-二极管阵列检测器(HPLC-DAD)测定猪肾中三聚氰胺含量的分析方法。利用乙腈、水和HCl混合提取液或三氯乙酸(1+99)溶液涡旋、超声萃取样品中的三聚氰胺,将提取液离心、过MCX阳离子交换柱后采用HPLC-DAD进行检测。在0.5~100 mg/L范围内具有良好的线性关系,RSD5%(n=7);检测限(S/N=10)为1 mg/kg。应用所建立的方法测定了猪肾、饲料、猪尿、猪肉等样品中的三聚氰胺含量。     

亲水作用色谱-电喷雾串联质谱法检测原料奶及奶制品中的三聚氰胺

建立了亲水作用色谱-电喷雾串联质谱测定原料奶及奶制品中三聚氰胺的方法。样品采用1%三氯乙酸水溶液-乙腈（体积比为1∶1）混合溶液提取,混合型阳离子交换反相固相萃取柱（MCX）富集净化,亲水作用色谱柱分离,电喷雾串联四极杆质谱仪进行检测。结果表明,三聚氰胺的质量浓度在0.05～10.0 mg/L范围内具有良好的线性关系。原料奶及奶制品中的三聚氰胺在0.5,2.5和10 mg/kg 3个添加水平下,平均回收率为76.3%～98.7%,相对标准偏差均小于6.8%;定量限（S/N＞10）为0.05 mg/kg。     

亲水作用色谱-串联质谱法测定化妆品中三聚氰胺残留量

建立了化妆品中三聚氰胺的亲水作用色谱-质谱联用（HILIC-MS/MS）检测方法。样品经三氯乙酸溶液提取（脂溶性样品再经正己烷萃取)后,用混合型阳离子交换(MCX)反相固相萃取柱富集净化,用5 mmol/L乙酸铵水溶液(含0.1%甲酸)和乙腈作为流动相,以梯度洗脱方式在ZIC-HILIC色谱柱上实现分离,以电喷雾离子源正离子(ESI+)模式进行质谱分析。三聚氰胺在0.02～0.5 mg/L范围内呈良好线性关系,相关系数为0.9985;方法的检出限(LOD,信噪比(S/N)≥3)为5.0 μg/kg,定量限(LOQ,S/N＞10)为20.0 μg/kg;在0.01～0.1 mg/kg添加浓度范围内,三聚氰胺的平均回收率为84.7%～93.4%,相对标准偏差为4.5%～8.4%。该方法能满足化妆品中三聚氰胺残留量的检测。     

固相萃取-高效液相色谱法测定焦糖色素中副产物2-甲基咪唑、4-甲基咪唑和2-乙酰基-4-(1,2,3,4-四羟基丁基)咪唑

建立了固相萃取法结合高效液相色谱同时检测焦糖色素中2-甲基咪唑(2-Methylimidazole,2-MEI)、4-甲基咪唑(4-Methylimidazole,4-MEI)和2-乙酰基-4-(1,2,3,4-四羟基丁基)咪唑(2-Acetyl-4-(1,2,3,4-tetrahydroxybutyl) imidazole,THI)的方法.样品经加水涡旋提取后,经混合型强阳离子交换固相萃取小柱富集净化,以乙腈-0.05％氨水(10∶90,V/V)为流动相,流速为0.6 mL/min,用反向色谱柱Polaris C18-A(250 mm×4.6 mm,5μm)柱分离,分别在二极管阵列检测器215 nm波长条件下检测焦糖色素中的2-甲基咪唑、4-甲基咪唑和287 nm波长条件下检测2-乙酰基4.(1,2,3,4-四羟基丁基)咪唑的含量.2-甲基咪唑、4-甲基咪唑和2-乙酰基-4-(1,2,3,4-四羟基丁基)咪唑在0.2～ 20 mg/L之间线性关系良好(r＞0.9996),在10,25和100 mg/kg添加浓度的回收率范围为75.3％ ～93.4％,相对标准偏差均小于10％,检出限分别为为2.6,3.0和1.5 mg/kg,定量限分别为8.5,10.0和5.0 mg/kg.     

气相色谱-质谱法测定鸡蛋中三聚氰胺

建立了气相色谱-质谱法测定鸡蛋中三聚氰胺的方法. 鸡蛋样品经三氯乙酸提取,乙酸铅沉淀蛋白后,过MCX阳离子交换固相萃取小柱除去样品基质干扰,用N,O-双三甲基硅基三氟乙酰胺(BSTFA)+三甲基氯硅烷(TMCS)(99+1)衍生,进行气相色谱-质谱分析. 在0.010~2.00 mg/L浓度范围内,线性关系良好(r=0.9996),检出限为0.01 mg/kg. 方法回收率为90.1%~94.7%,RSD为1.7%~5.3%. 方法准确、灵敏,适用于鸡蛋中三聚氰胺的检测.     

气相色谱-质谱联用法同时测定乳及乳制品中的三聚氰胺及肌酐

建立了同时测定乳制品中三聚氰胺及肌酐的气相色谱-质谱联用方法。样品经1%三氯乙酸溶液萃取,混合型阳离子交换固相萃取净化,提取液用氮气吹干后加入N,O-双(三甲基硅基)三氟乙酰胺-三甲基氯硅烷(BSTFA-TMCS)硅烷化试剂,于75 ℃下衍生60 min,最后采用选择离子模式下的气相色谱-质谱测定。三聚氰胺和肌酐的定量限分别为0.10 mg/kg和0.20 mg/kg;在0.1～50 mg/L范围内的线性相关系数均大于0.99。实际样品中,肌酐在10～100 mg/kg和三聚氰胺在0.1～5.0 mg/kg添加范围内的回收率分别为80.7%～116.8%和77.6%～107.5%,相对标准偏差分别小于9.4%和8.5%。该方法能有效除去干扰,灵敏度高,回收率较好,可用于乳制品中三聚氰胺和肌酐的同时测定。     

柱后衍生液相色谱法测定粮食中草甘膦和氨甲基磷酸残留量

建立了固相萃取-高效液相色谱(HPLC)柱后衍生荧光检测粮食中草甘膦(GLY)和氨甲基磷酸(AMPA)残留的测定方法.样品中分析物用水提取,强阳离子柱(SCX)净化,钾离子交换柱分离,柱后采用次氯酸钠(NaClO)和邻苯二甲醛(OPA)、巯基乙胺衍生化,最终为荧光检测器(FLD)所分析.草甘膦和氨甲基磷酸在0～20 mg/L范围内线性良好,相关系数达0.9966和0.9999;在精米和小麦粉1、5、10 mg/kg 3个添标水平上,平均回收率(重复3次)在83.2%～119.1%之间;7次测量精密度分别为2.86%和4.86%;样品稀释22.22倍,方法的检出限为0.5 mg/kg.     

亲水作用毛细管整体柱的制备及其用于奶制品中三聚氰胺的加压毛细管电色谱分析

以甲基丙烯酸丁酯(BMA)和3-［N,N-二甲基-［2-(2-甲基丙-2-烯酰氧基)乙基］铵］丙烷-1-磺酸内盐(SPE)为单体,制备了新型的亲水作用毛细管整体柱,并通过三聚氰胺在此柱上的保留行为证明其具有亲水性。以加压毛细管电色谱(pCEC)技术为平台,优化了整体柱基于亲水作用分离分析奶制品中三聚氰胺的色谱条件。当流动相中乙腈与10 mmol/L磷酸盐缓冲液的体积比为80:20, pH为3.0,电压为3 kV,检测波长为215 nm时,三聚氰胺能获得很好的分离。方法学考察结果表明,合成的亲水整体柱具有良好的重现性和渗透性,建立的pCEC分析方法的检出限为0.05 mg/L。该方法简单方便,回收率较高,而且流动相中无需添加离子对试剂,适合于奶制品中三聚氰胺的定量测定。     

高效液相色谱法检测水产品中三聚氰胺的残留量

建立了水产品肌肉组织中三聚氰胺的高效液相紫外检测法.肌肉组织中加入三氯乙酸作为提取剂,乙酸铅沉淀蛋白,过PCX混合阳离子交换柱净化等样品处理过程;乙腈-10 mmol庚烷磺酸钠+10 mmol柠檬酸溶液 (8∶92,V/V)为流动相,紫外检测波长为240 nm.方法在0.100～10.00 mg/L浓度范围内呈线性相关,相关系数r=0.999 9.平均回收率为74.29%～ 89.04%,相对标准偏差为0.44%～9.32%,三聚氰胺在水产品肌肉中的检测限为0.1 mg/kg.方法适用于水产品肌肉组织中三聚氰胺残留量的检测.     

基于QuEChERS前处理技术和弱阳离子交换色谱的牛奶和奶粉中三聚氰胺的快速检测方法

应用QuEChERS前处理技术,并结合弱阳离子交换色谱,建立了牛奶和奶粉中三聚氰胺的快速检测方法。样品使用医用酒精(乙醇含量75%)和一种新型脂肪吸附(LAS)材料超声振荡处理,在沉淀(吸附)蛋白质和脂肪的同时提取三聚氰胺,然后经8000 r/min离心,上清液过膜直接分析。色谱分析在弱阳离子交换色谱柱(WCX)上进行,采用2 mmol/L pH为3.8的磷酸二氢钾水溶液为流动相,在5 min内实现分离分析。结果表明,该方法在0.02～20 mg/L内线性相关系数大于0.9999。在1～50 mg/kg添加浓度范围内,牛奶的平均回收率为98.9%～105.2%,相对标准偏差(RSD)为0.9%～3.4%;奶粉的平均回收率为86.4%～102.9%, RSD为1.5%～6.7%。本方法的检出限为0.05 mg/kg(牛奶)和0.1 mg/kg(奶粉)。整个分析检测过程没有使用有毒有害有机溶剂,是一种绿色的分析方法。     

聚合物整体柱微萃取-高效液相色谱法检测鸡蛋中的磺胺嘧啶和磺胺二甲嘧啶残留

建立了鸡蛋中磺胺嘧啶和磺胺二甲嘧啶残留量的聚合物整体柱微萃取和高效液相色谱检测方法。以聚(甲基丙烯酸-乙二醇二甲基丙烯酸酯)毛细管整体柱作为萃取装置。为了得到较高的萃取效率,优化了影响萃取效率的参数(萃取流速、萃取体积、样品基质pH值)。样品经过匀浆、乙醇提取、磷酸盐缓冲溶液稀释、离心等步骤后直接进行萃取。鸡蛋中磺胺嘧啶和磺胺二甲嘧啶的检出限分别为11.2 ng/g和8.8 ng/g,在50～5000 ng/g的浓度范围内具有良好的线性关系。加标回收率大于65%,日内、日间测定的相对标准偏差不高于8.2%。结果表明,方法简单、快速、灵敏度高,适用于鸡蛋中磺胺嘧啶和磺胺二甲嘧啶的常规分析。     

Rapid determination of Δ-Tetrahydrocannabinol in saliva by polymer monolith microextraction combined with gas chromatography-mass spectrometry

A method was developed for the determination of Δ⁹-Tetrahydrocannabinol (THC) in saliva by polymer monolith microextraction (PMME) combined with gas chromatography-mass spectrometry. The poly(methacrylic acid-co-ethylene glycol dimethacrylate) (p(MAA-co-EGDMA)) monolithic capillary column was selected as the extraction medium of PMME, which showed high extraction capacity towards THC in saliva. To reach optimum PMME extraction performance, several PMME parameters were investigated, including matrix pH, flow rate for extraction, sampling volume and elution solvent. Under the optimal conditions, good extraction efficiency was obtained with no matrix interference in the process of extraction and the subsequent GC-MS analysis. In the selected-ion monitoring (SIM) mode, the limit of detection (LOD) for THC was 0.68 ng/mL. The linearity range of the method was 3-300 ng/mL. Excellent reproducibility of the method was exhibited by intra- and inter-day precisions, yielding the relative standard deviations (R.S.D.s) less than 12%; recoveries higher than 89%. The proposed method was proved to be rapid, sensitive, and competently applied to the determination of THC in saliva samples.     

Multiresidue analysis of beta-agonists in pork by coupling polymer monolith microextraction to electrospray quadrupole time-of-flight mass spectrometry

A novel method of polymer monolith microextraction (PMME) using poly(methacrylic acid-co-ethylene glycol dimethacrylate) monolith combined with electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-QTOF MS) was developed for the rapid and sensitive determination of beta-agonists in pork samples. The conditions of PMME were optimized for the improvement of extraction efficiency and reduction of the matrix interferences from pork. Under the optimal condition, the eluate solution allowed direct analysis by mass spectrometry. In the positive ion mode and in the multiple reaction monitoring (MRM) mode, the limits of detection (LODs) for beta-agonists were found to be 0.08 ng/g (clenbuterol, CLB), 0.18 ng/g (salbutamol, SBTM) and 0.26 ng/g (terbutaline, TBTL) in pork, respectively, with good inter- and intra-day precisions (2-10% for CLB, 11-23% for SBTM and 4-16% for TBTL). The proposed PMME/ESI-QTOF MS method was successfully applied to the determination of beta-agonist residues in thirteen real samples, and the positive samples were confirmed according to the identification points (IPs) system defined by Commission Decision 2002/657/EC. To investigate the matrix effect, the proposed method was compared with PMME-HPLC/ESI-QTOF MS and the slight decrease in sensitivity of PMME/ESI-QTOF MS was ascribed to the inter-analyte ion suppression.     

Polymer Monolith Microextraction Coupled with HPLC for Determination of Jasmonates in Wintersweet Flowers

A simple, fast, and effective method has been presented for the determination of jasmonates in plant samples by polymer monolith microextraction (PMME). A poly (methacrylic acid-ethylene glycol dimethacrylate) (MAA-EGDMA) monolith-based device was developed for extraction, purification, and concentration; HPLC-UV was used for evaluation. To realize the best microextraction efficiency, parameters such as sample pH value, flow rate, and sample volume were systematically examined and optimized. Aqueous solution (5 mL) of jasmonates at pH 3.0 was selected as sample solution, and loaded onto the monolith at flow rate of 0.15 mL/min; finally, 50 μL of acetonitrile was used for elution. The proposed method exhibited impressive enrichment efficiency (almost 100-fold) and the limits of detection for jasmonic acid and methyl jasmonate obtained 0.5 and 2 ng/mL by using UV detection. Wide linear ranges were also observed (2–2000 and 5–2000 ng/mL) for both jasmonic acid and methyl jasmonate, with R² > 0.999. The developed PMME-HPLC method was successfully applied to the determination of jasmonates in fresh wintersweet flowers with recoveries in the range of 91.9–97.2%. The result was confirmed by an HPLC-MS method. The PMME method was also compared with a conventional C18-SPE method and exhibited better clean-up efficiency.     

Preparation, evaluation and application of molecularly imprinted solid-phase microextraction monolith for selective extraction of pirimicarb in tomato and pear

A simple, rapid and sensitive method for the determination of pirimicarb in tomato and pear using polymer monolith microextraction (PMME) based on the molecularly imprinted polymer (MIP) monolith combined with high-performance liquid chromatography-photodiodes array detector (HPLC-PAD) was developed. By optimizing the polymerization conditions, such as the nature of porogenic solvent and functional monomer, the molar ratio of the monomer and cross-linker, an pirimicarb MIP monolith was synthesized in a micropipette tip using methacrylic acid (MAA) as the functional monomer, ethylene dimethacrylate (EGDMA) as the cross-linker and the mixture of toluene-dodecanol as the porogenic solvent. The MIP monolith showed highly specific recognition for the template pirimicarb. The monolith was applied for the selective extraction of pirimicarb in tomato and pear. Several parameters affecting MIP-PMME were investigated, including the nature and volume of extraction solvent, sample volume, flow rate and sample pH. Under the optimum PMME and HPLC conditions, the linear ranges were 2.0-1400 μg/kg for pirimicarb in tomato and pear with the correlation coefficient of above 0.999. The detection limits (s/n=3) were both 0.6 μg/kg. The proposed method was successfully applied for the selective extraction and determination of pirimicarb in tomato and pear.     

Polymer monolith microextraction with in situ derivatization and its application to high-performance liquid chromatography determination of hexanal and heptanal in plasma

A simple, rapid and sensitive method for the determination of hexanal and heptanal in plasma by high-performance liquid chromatography (HPLC) has been developed, which is based on polymer monolith microextraction (PMME) with in situ derivatization. 2,4-dinitrophenylhydrazine (DNPH) as a derivatizing reagent was first adsorbed on a poly (methacrylic acid-co-ethylene glycol dimethacrylate) (MAA-EGDMA) monolith, and then microextraction was performed simultaneously with derivatization on the monolith. The several parameters affecting the in situ derivatization simultaneously with PMME were investigated, including the flow rate, pH, buffer concentration, and temperature. The whole pretreatment process can be accomplished within 8 min. The limits of detection for hexanal and heptanal were found to be 2.4 and 3.6 nmol/L, respectively. The recoveries in plasma sample were in the range of 83-87% with the inter- and intra-day precisions less than 6.8%. This method was successfully applied to the analysis of hexanal and heptanal in plasma samples from different cancer patients.     

Determination of low-aliphatic aldehyde derivatizatives in human saliva using polymer monolith microextraction coupled to high-performance liquid chromatography

In this study, a polymer monolith microextraction (PMME) using a poly (methacrylic acid-ethylene glycol dimethacrylate) (MAA-EGDMA) monolith in conjunction with high-performance liquid chromatography (HPLC) was developed for the determination of 2,4-dinitrophenylhydrazine (DNPH) derivatives of several aldehydes in human saliva. The conditions for the labeling reactions of aldehydes with DNPH and followed extraction of the derivatives were optimized. The precision, recovery and detection limits were evaluated with spiked saliva. The limits of detection ranged from 0.43 to 1.40 μg/L. The inter-and intra-day relative standard deviations were less than 10%. The proposed method was successfully applied to the determination of aldehydes in saliva samples from a non-smoker, a passive smoker and a heavy smoker.     

Multiresidue determination of sulfonamides in chicken meat by polymer monolith microextraction and capillary zone electrophoresis with field-amplified sample stacking

A method based on poly(methacrylic acid-co-ethylene glycol dimethacrylate) (MAA-EGDMA) monolith microextraction (PMME) and online preconcentration technique of field-amplified sample stacking (FASS) was proposed for sensitive capillary electrophoresis-ultraviolet (CE-UV) analysis of 12 sulfonamides (sulfamethazine, sulfamethoxypyridazine, sulfathiazole, sulfamerazine, sulfameter, sulfadoxine, sulfadimethoxine, sulfamonomethoxine sodium, sulfachlorpyridazine, sulfamethoxazole, sulfamethizole, and sulfisoxazole) in chicken samples. The conditions of PMME were optimized for the improvement of extraction efficiency and reduction of the matrix interferences from chicken sample. The best separation was achieved within 15min using a buffer of 100mM phosphate electrolyte (pH 7.3) with temperature and voltage of 20 degrees C and 25kV, respectively. By applying FASS, detection limits of 3.49-16.7ng/g were achieved with satisfactory precision (RSD<==13%) and recovery (96.3-104%) over a linear range of 50-1000ng/g for most analytes.     

Multiresidue determination of (fluoro)quinolone antibiotics in chicken by polymer monolith microextraction and field-amplified sample stacking procedures coupled to CE-UV

Simultaneous determination of 9 (fluoro)quinolone antibiotics (FQs) was accomplished by capillary electrophoresis-ultraviolet (CE-UV) based on poly(methacrylic acid-co-ethylene glycol dimethacrylate) (MAA-EGDMA) monolith microextraction (PMME) coupled with on-line preconcentration technique of field-amplified sample stacking (FASS). The effects of composition of the acid and organic solvent in the sample solution, sampling time, and voltage on the efficiency of the sample stacking have been systematically investigated. Several parameters that influence extraction efficiency for PMME such as pH of sample solution, extraction volume, and wash and desorption conditions were optimized. In the proposed method, a substantial increase in sensitivity for all the FQs tested was achieved by the combination of PMME procedure with on-line preconcentration of FASS prior to CE analysis. Good linearities were obtained for the 9 tested FQs with the correlation coefficients (R) above 0.9954. The limits of detection (S/N = 3) were found to be 2.4-34.0 ng g⁻¹ and the recoveries ranged from 81.2 to 100% with relative standard deviations less than 11.3%. The proposed PMME-FASS-CE method was applied to the determination of FQs residues in chicken samples.