超高效液相色谱-串联质谱法测定鸡肉、鸡蛋中氟苯尼考和氟苯尼考胺残留

目的建立超高效液相色谱-串联质谱准确测定鸡肉、鸡蛋中氟苯尼考和氟苯尼考胺残留的分析方法。方法鸡肉和鸡蛋样品加入D5-氯霉素内标,经氨化乙酸乙酯混合溶液超声离心提取,提取液减压蒸馏浓缩后,C18固相萃取柱净化处理,采用超高效液相色谱-串联质谱法对氟苯尼考和氟苯尼考胺同时进行检测。结果氟苯尼考线性范围为0.2～20μg/L,检出限为1.0μg/kg,定量限为3.0μg/kg,方法回收率为88.0%～108.0%,相对标准偏差为4.7%～6.4%;氟苯尼考胺线性范围为0.2～20μg/L,检出限为1.0μg/kg,定量限为3.0μg/kg,方法回收率为76.0%～93.1%,相对标准偏差为4.1%～7.2%。结论本方法精确、重现性好,适用于鸡肉、鸡蛋中氟苯尼考和氟苯尼考胺残留量的测定。     

高效液相色谱-内标法测定香辛料中15种多环芳烃类污染物(PAHs)

该研究建立了高效液相色谱（High Performance Liquid Chromatography,HPLC）同时分析香辛料中15种多环芳烃类污染物（Polycyclic Aromatic Hydrocarbons,PAHs）含量的内标检测方法。样品经氢氧化钠溶解,乙腈萃取,正己烷复溶后,过弗罗里硅土（Florisil）小柱净化浓缩,供HPLC检测,苯并[a]芘-D12作为内标定量。该方法在0~100 ng/mL内线性关系良好,辣椒中PAHs检出限：0.5~3.0 μg/kg;定量限2.0~10.0 μg/kg;花椒中检出限：0.5~1.0 μg/kg;定量限2.0~3.0 μg/kg。在2.0、10.0、50.0 μg/kg 3个浓度水平,辣椒中回收率范围为60.58%~119.48%,相对标准偏差（Relative Standard Deviations,RSD）（n=6）为1.25%~9.61%,花椒中回收率为60.46%~119.24%,RSD（n=6）为1.10%~8.56%。5种地产香辛料中ΣPAHs 含量由高到低为：青花椒（561.2 μg/kg）＞二荆条（448.8 μg/kg）＞红花椒（358.3 μg/kg）＞石柱红（353.6 μg/kg）＞小米辣（243.5 μg/kg）,区县种植基地污染较严重的为璧山、江津和荣昌,ΣPAHs分别为721.5、626.6和621.0 μg/kg,PAHs中污染较严重的化合物为菲、荧蒽和芘,平均含量分别为215.10、80.25和75.35 μg/kg。该研究建立的内标法准确度高,重复性好,适用于香辛料及制品中PAHs检测。     

SPE结合GC/MS测定黄酒中氨基甲酸乙酯

氨基甲酸乙酯（EC）是一种致癌物,黄酒中含量较高。采用固相萃取法提取黄酒中的EC,浓缩后进行GC/MS分析,SIM模式下内标法定量。方法回收率100.5%～106.2%,相对标准偏差为3.0%,方法检出限为0.54μg/kg,定量限为1.80μg/kg,方法准确可靠。采用本法测定10种市售黄酒,其EC含量为176.15～345.53μg/kg。     

凝胶渗透色谱-超高效液相色谱-串联质谱测定茶叶中吡虫啉和啶虫脒

建立用凝胶渗透色谱-超高效液相色谱-串联质谱仪测定茶叶中吡虫啉和啶虫脒残留的方法。样品经乙酸乙酯-环己烷（1∶1,V/V）溶液涡旋混匀后超声提取,经凝胶渗透色谱净化后,采用超高效液相色谱-串联质谱仪测定。结果显示,2 种农药在0.5～100 μg/L范围内线性良好,相关系数R2均大于0.99。吡虫啉和啶虫脒的检出限分别为2.0 μg/kg和1.0 μg/kg,定量限分别为5.0 μg/kg和3.0 μg/kg。吡虫啉和啶虫脒在3 个水平的加标平均回收率为76.94%～91.68%,相对标准偏差为2.67%～7.90%。     

液相色谱串联质谱法测定纺织品中PFOS和PFOA

针对国际对纺织品中全氟辛磺酸(PFOS)和全氟辛酸(PFOA)的限量要求,采用ASE-300快速溶剂萃取仪提取样品中PFOS和PFOA,经浓缩、净化、过膜、定容后用液相色谱串联质谱法测定,外标法定量。采用选择离子检测进行阳性确证,建立纺织品中PFOS和PFOA的检测方法。该方法的最低检出限、线性范围和方法回收率对PFOS为1.0μg/kg、3.0~300μg/kg和82.35%~105.60%;对PFOA为0.5μg/kg、1.5~200μg/kg和85.17%~107.78%。     

在线凝胶渗透色谱-气相色谱-串联质谱法测定食用植物油中11种有机磷阻燃剂

建立在线凝胶渗透色谱–气相色谱-串联质谱法(GPC-GCMS/MS)测定食用植物油中11种有机磷阻燃剂的分析方法。0.5 g食用油样品用(3∶7)丙酮/环己烷溶液稀释定容5 mL,GPC-GCMS/MS采用多反应监测模式(MRM)测定,外标法定量。11种有机磷阻燃剂在1～50μg/L范围内,线性关系良好,相关系数r>0.997 0,方法检出限为1.0～3.0μg/kg,定量限为3.0～9.0μg/kg。空白样品中添加3个水平质量浓度,回收率在65.6%～129.0%之间,相对标准偏差RSD为0.2%～13.9%。该方法样品前处理简单,仪器自动化程度高,重复性较好,适用于食用植物油中有机磷阻燃剂的检测。     

肉制品中N-二甲基亚硝胺测定及不确定度评定

建立气相色谱/三重四级杆质谱法测定肉制品中N-二甲基亚硝胺的方法,并对测定过程中可能引入的不确定度进行分析和评定。试样经QuEChERS方法提取后采用MRM模式进行定性定量;建立不确定度评定的数学模型,确定并简化不确定度来源,计算合成不确定度和扩展不确定度。加标回收率范围为87.8%~115.3%,相对标准偏差(RSD)在4.3%~6.2%,线性相关系数达0.999 5,实际分析15份样品中检出5份阳性样品,含量均低于国家限量值3.0μg/kg;测定3.0μg/kg时,N-二甲基亚硝胺的含量是(3.0±0.18)μg/kg,相对扩展不确定度为6.0%。该试验方法步骤简单、有机溶剂用量少、灵敏度高,重现性好,满足国家限量检测的要求;本方法适用于GC-MS/MS测定肉制品中N-二甲基亚硝胺的不确定度评定。     

QuEChERS-高效液相色谱-串联质谱法测定鸡蛋中38种药物残留

目的建立高效液相色谱-串联质谱法(high performance liquid chromatography-tandem mass spectrometry, HPLC-MS/MS)测定鸡蛋中38种药物残留的分析方法。方法样品采用0.1 mol/L乙二胺四乙酸二钠(ethylene-diamine-tetra-acetate,EDTA)和乙腈提取,经QuEChERS净化后,通过LC-MS/MS测定,外标法定量。结果鸡蛋中38种药物在0.3～100μg/kg浓度范围内相关系数(r~2)在0.99138～0.99989之间,线性关系良好。方法检出限0.05～1.0μg/kg,定量限0.1～3.0μg/kg,在3.0、10.0、50.0μg/kg 3个添加水平的平均回收率72.49%～114.06%,相对标准偏差(n=6)2.37%～13.85%。结论本方法操作简便快速、灵敏稳定,适用于鸡蛋中多种药物残留的高通量快速检测。     

改进的QuEChERS-气相色谱-质谱法测定中式腊肉中8 种挥发性N-亚硝胺

基于改进的QuEChERS法建立测定中式腊肉中8 种挥发性N-亚硝胺的气相色谱-质谱检测方法,并应用于市售样品的初步风险评估。样品经乙腈超声提取、冷冻和N-丙基乙二胺净化后水浴氮吹浓缩定容至微量体积;目标物经极性毛细管柱分离后以选择离子监测模式和外标法定量。结果表明,8 种N-亚硝胺在对应质量浓度范围内线性关系良好（R2＞0.997）,基质效应为0.86～0.98;检出限为0.05～0.14 μg/kg,定量限为0.15～0.47 μg/kg;低、中、高3 个含量（0.3、1.0、3.0 μg/kg）加标回收实验的平均回收率为71.3%～94.1%,相对标准偏差（n=6）为0.4%～11.2%;12 份代表性市售样品中仅1 份样品的N-亚硝基二乙胺含量（3.06 μg/kg）超标,其余均低于单项和总挥发性N-亚硝胺的限量水平（3.0 μg/kg和10.0 μg/kg）。该方法净化效果好、成本低,检测灵敏、结果准确,适用于中式腊肉中8 种挥发性N-亚硝胺的检测;目前市售中式腊肉中N-亚硝胺的风险水平整体较低。     

QuEChERS-超高效液相色谱-串联质谱法同时测定动物源性食品中5种双酰胺类杀虫剂的残留

目的 采用超高效液相色谱-串联质谱方法检测猪肉、猪肝、鸭肉、鸡肉和鱼肉等动物源性食品中5种双酰胺类杀虫剂(氟苯虫酰胺、氯虫苯甲酰胺、溴氰虫酰胺、四氯虫酰胺、环溴虫酰胺)的残留量。方法 采用QuEChERS样品前处理技术,样品经乙腈水提取,提取液用1 g无水硫酸镁和2 g氯化钠脱水,150 mg N-丙基乙二胺、150 mg C₁₈和400 mg无水硫酸镁净化,以乙腈-5 mmol/L乙酸铵溶液作为流动相,经ACQUITY UPLC BEH C₁₈色谱柱梯度洗脱分离,电喷雾离子源离子化,负离子多反应监测模式检测。结果 5种双酰胺类杀虫剂在2～50 ng/mL的质量浓度范围内线性关系良好,相关系数(r)大于0.999 0,在3.0 μg/kg、6.0 μg/kg和12.0 μg/kg 3个添加水平下,5种双酰胺类杀虫剂的回收率范围为79.6%～112.4%,相对标准偏差(relative standard deviations, RSD)为0.6%～6.9% (n=6),方法检出限和定量限范围分别为0.7～1.0 μg/kg和2.0～3.0 μg/kg。结论 本方法操作简单、灵敏度和准确度高、重现性好,可同时检测动物源性食品中5种双酰胺类杀虫剂的残留量,为其日常监管提供了技术支持。     

食品中防腐剂双乙酸钠检测方法的研究——高效液相色谱法

采用高效液相色谱仪（配紫外检测器）摸索出食品中双乙酸钠出峰的色谱条件和糕点、豆制品等食品的前处理方法，并且与其他相关类型防腐剂进行了排查，进行准确的定性和定量测定的研究。标准曲线有较好的线性关系，方法回收率达95％；RSD〈3．0％，精密度高；最低检测浓度为0．01g／L。     

Detection and classification of the spliced yarn joint using vector quantization and dynamic time warping

This paper presents an automatic vision based system for unsupervised detection and classification of spliced yarn joint. In the splice detection process, a competitive learning method based on LBG algorithm is used. In the splice classification process, a dynamic time warping (DTW) algorithm is used to classify the extracted splice joint into one of three degrees of quality based on the degree of similarity between the spliced joint and the non-spliced part of the same yarn. The use of DTW in the classification makes the proposed method adaptable to different types of yarns. Consequently, this method might be globally optimal for classification of all spliced yarn joints. The proposed method has been evaluated using three sorts of experiments. One hundred and twenty images containing different grades of joint quality have been used in the first experiments, where 97.5% detection rate and 95.8% classification accuracy were achieved. In the second experiment, 280 standard images that represent high quality reference images of 12 groups of spliced yarns are used. In this experiment 97.1% detection rate and 100% classification rate have been achieved. Moreover, the method has been tested using the Murata Image Database; this is a large set of high quality images of splice joints for different yarn types.     

螯合萃取石墨炉原子吸收光谱法测定食品中的砷

采用石墨炉原子吸收技术研究了食品中砷的测定方法。选择ＡＰＤＣ－ＭＩＢＫ萃取分离体系使砷与基体分离；采用硝酸镁＋硝酸镍作混合基体改进剂，将灰化温度提高到１１００℃，消除了共存阴、阳离子的干扰。方法检出限１．６ｎｇ／ｍｌ，２ｇ样品的最低检出浓度为６．０ｎｇ／ｇ，相对标准偏差小于１４％，平均加标回收率为９９．１±６．９％。本法具有干扰少，灵敏度高等特点。     

Optimization of Solvent Extraction and Direct Transmethylation Methods for the Analysis of Egg Yolk Lipids

The composition of egg yolk lipids differs greatly from most other food lipids, as it combines high contents of triglycerides and phospholipids, as well as a high proportion of cholesterol. The lipids are organized in lipoproteins and are dispersed in aqueous phase. Classical extraction methods using chloroform and methanol have not been optimized for such a matrix, therefore quantitative extraction yields of egg lipids can be inaccurate. In this study, the original method of Bligh and Dyer is evaluated and adapted for egg lipids. Furthermore, a direct extraction/derivatization method is presented. Solvent extraction resulted in a lipid yield of 31.8 ± 0.89% and total fatty acid yield was 257 ± 2 mg/g yolk whereas the direct method yielded 250 ± 7 mg/g yolk. Gas chromatographic analyses confirmed that lipid recovery was complete for triglycerides and phospholipids as well.     

Fast Separation of Capsaicinoids from Peppers by Reversed Phase Ultra-Performance Liquid Chromatography: Comparation with Traditional High-Performance Liquid Chromatography Methods

A new chromatographic method for the separation of major capsaicinoids in peppers has been developed. Nordihydrocapsaicin, capsaicin, dihydrocapsaicin, homocapsaicin, and homodihydrocapsaicin have been separated by reversed-phase ultra-performance liquid chromatography. A gradient method has been developed using two solvents: 0.1% acetic acid in water and 0.1% acetic acid in methanol. The developed method allows the full separation of capsaicinoids in less than 3 min, with high reproducibility (relative standard deviation < 4.3%) and repeatability (relative standard deviation < 3.6%). Robustness regarding the total amount of methanol in the sample was determined. Comparison with previous reversed-phase high-performance liquid chromatography methods using both monolithic and conventional columns was also studied. Finally, the method was applied in the determination of major capsaicinoids in 16 hot pepper samples produced in Spain.     

Measurement of malondialdehyde in fish: A comparison study between HPLC methods and the traditional spectrophotometric test

Alternative methods to the traditional spectrophotometric determination of the malondialdehyde-thiobarbituric acid (MDA-TBA) complex (method A) and to the overestimation of MDA levels in the TBA reaction have been develop for the evaluation of lipid oxidation in fish. In this study, two HPLC separation methods of the MDA-TBA (method B) and MDA-dinitrophenylhydrazine (MDA-DNPH) adduct (method C) were investigated and compared to the traditional spectrophotometric TBA test (method A) in samples of chilled fish (hake, sea bream and sardine). Detection limits were 0.16, 0.10 and 0.20 μM MDA and quantification limits were 0.23, 0.17 and 0.26 μM MDA, for methods A, B and C, respectively. Recovery of method B ranged between 100% and 108% and of method C between 90% and 112%. Method A presented low recovery levels (under 71%). Overall method performance followed the order HPLC method MDA-DNPH > HPLC method MDA-TBA > traditional spectrophotometric TBA test. Though showing a better accuracy and specificity, method C had, however, some disadvantages, a relatively high limit of detection (0.20 μM MDA) and a lower reproducibility at lower MDA contents in standards and samples. Nevertheless, these are not critical drawbacks for an application in routine fish analysis, given the high MDA concentrations in oxidised fish. The application of the modified HPLC methods in fish samples with different levels of MDA, showed that these methods are useful for the samples with low amounts of oxidation products, such as chilled hake as well as in samples with high levels of oxidation, like 15 days chilled stored sardine.     

离子迁移谱快速测定纺织品内高关注物质

随着欧盟REACH法规的实施,受限的高关注物质不断增加。针对法规对这些物质限量0．1％的要求,介绍了一种使用离子迁移谱技术定性筛选纺织品中此类物质的方法。与经典方法如气相色谱一质谱联用法和高效液相色谱法相比,该方法具有方便快捷的特点,可应用于多种高关注物质的筛查分析,大大缩短了检测周期,并为现场检测提供了可能。     

山药粉丝的研制

采用去皮、护色、打浆、配方、制丝等过程研究了山药粉丝的制作工艺,并对影响山药粉丝的色、香、味、黏度、柔软性等的因素进行了探讨。通过对魔芋精粉、柠檬酸、明矾、增稠剂添加量的正交实验及单因素实验得出了生产山药粉丝的最佳原辅料配方及生产工艺。结果表明:2%魔芋精粉、0.1%柠檬酸、0.5%明矾、0.05%卡拉胶最佳。采用该技术条件能得到具有独特风味的高质量产品。     

Electrochemical determination of vitamin E in margarine, butter and palm oil.

A simple, rapid and reproducible method is described for the analysis of tocopherols in margarine, butter and palm oil. The method involves saponification, extraction of the unsaponifiable material and direct voltammetric determination. No separation technique is necessary. Two indicator electrodes, glassy carbon (GCE) and carbon paste (CPE), have been employed in this work, GCE in ethanol-benzene (2:1) medium and CPE in 75% ethanol. The CPE gives over ten times as much current as the GCE for a given tocopherol concentration. The GCE' high residual current in aqueous medium makes it impractical in 75% aqueous ethanol and the CPE' solubility in benzene restricts its usage in ethanol-benzene medium. Slight turbidity does occur sometimes when the unsaponifiable material of the samples is dissolved in 75% ethanol but this seems not to interfere in subsequent analysis. Increase in ethanol content to 90% gives a clearer solution and higher background, but no appreciable difference in the results. The results obtained by use of both electrodes are given and shown to be in close agreement with previously published results.     

Determination of phenolic compounds in olive oil: New method based on liquid–liquid micro extraction and ultra high performance liquid chromatography-triple–quadrupole mass spectrometry

A novel analytical approach has been performed and evaluated for the identification and quantification of phenolic compounds (phenolic alcohols, secoiridoid derivates, lignans, flavonoids, phenolic acids and aldehydes) which can be found in both virgin olive oil (VOO) and extra virgin olive oil (EVOO). An improved liquid–liquid micro extraction (LLME) method combining with ultra high performance liquid chromatography (UHPLC) coupled to electrospray ionization source (ESI) and tandem mass spectrometry (MS/MS) in Dynamic Multiple Reaction Monitoring (DMRM) mode has been developed, reducing the amount of sample, reagents and time consumed. The proposed methodology was applied to standard solutions, and the quality control parameters obtained were compared with those achieved in spiked refined olive oil (SROO). Generally, these parameters showed lower values in SROO than in standard solutions. Matrix effect, recovery and process efficiency have been studied using SROO. The recoveries were around 90% and the process efficiency of the whole method was higher than 80% for most of the phenolic compounds studied. Examination of these parameters revealed that work straight in the olive oil matrix, which is closer to behave as a real sample, provides better results. The applicability and reliability of this methodology have been confirmed using real samples.