对氯苯胺及其同分异构体的鉴别

为了分离对氯苯胺及其同分异构体，采用了气相色谱-质谱联用方法，通过改进色谱条件，分离了对氯苯胺及其同分异构体。试验结果表明，采用气-质联用仪可以鉴别对氯苯胺同分异构体。     

棉籽油脂肪酸甲酯化的方法及其脂肪酸含量分析

以新陆早39号以及新陆早50号的棉籽为材料,利用索氏提取仪提取其总油脂,分别采用三种常用的脂肪酸甲酯化方法:KOH-甲醇法,H₂SO₄-甲醇,14% BF₃-甲醇法进行甲酯化后,GC-MS上机分析;通过37种脂肪酸甲酯混标制定标准曲线,用外标法进行定量。结果表明:KOH-甲醇法甲酯化的脂肪酸GC-MS上机分析能检测到10种脂肪酸组分;H₂SO₄-甲醇与14% BF₃-甲醇法只能检测到6种。用KOH-甲醇法甲酯化后GC-MS测定表明,棉籽油脂肪酸以多不饱和脂肪酸的亚油酸为主,其次是饱和脂肪酸的棕榈酸以及单不饱和脂肪酸的油酸。在新陆早39号以及新陆早50号中,每克棉籽中亚油酸的含量分别达147.29 mg与163.2 mg,分别占其油脂含量的60.12%与60.83%;棕榈酸含量分别为65.05 mg与62.28 mg,分别占其油脂含量的26.55%与23.24%。油酸含量分别为24.79 mg与22.19 mg,分别占其油脂含量的10.12%和8.28%。结论:三种常用的脂肪酸甲酯化方法中,KOH-甲醇法更方便,快速,检测种类多,适用于棉籽脂肪酸的甲酯化。     

致癌芳香胺同分异构体鉴别方法研究

使用气相色谱-质谱联用仪(GC-MS)和快速液相色谱仪(RRLC)对各种致癌芳香胺同分异构体进行系统的分析。试验选取不同极性的色谱柱(气相色谱柱HP-5 MS、DB-200、DB-17 MS、液相色谱柱XDB C-18等)对分离条件进行比对优化,确定了每组同分异构体的最优分析条件,建立起一套有效区分各种致癌芳香胺同分异构体的鉴别方法,解除纺织及皮革产品可分解致癌芳香胺染料检验中的困扰。     

致癌芳香胺同分异构体鉴别方法研究

使用气相色谱-质谱联用仪（GC—MS）和快速液相色谱仪（RRLC）对各种致癌芳香胺同分异构体进行系统的分析。试验选取不同极性的色谱柱（气相色谱柱HP-5MS、DB-200、DB-17MS、液相色谱柱XDBC—18等）对分离条件进行比对优化．确定了每组同分异构体的最优分析条件,建立起一套有效区分各种致癌芳香胺同分异构体的鉴别方法,解除纺织及皮革产品可分解致癌芳香胺染料检验中的困扰。     

液相色谱串联质谱法实现二氨基甲苯同分异构体的分离鉴别

以ZORBAX Eclipse XDB-C18 Analytical 4.6mm×150mm,5-Micron柱为分析柱,甲醇-水为流动相,建立了高效液相色谱质谱联用仪测定生态检测中禁用芳香胺2,4-二氨基甲苯以及其同分异构体的方法.确定了质谱的最佳检测条件,碰撞电压为19ev和20ev;液相分离的最佳洗脱条件,用时为20min和15min.本方法简单、准确,适用于日常生态检测.     

丙烯酰胺的检测技术及在纺织品中检测研究进展

本文简要介绍了丙烯酰胺的检测技术应用情况以及在纺织品中丙烯酰胺的检测技术研究状况,对相关检测人员进行该物质的检测方法研究提供参考。     

高效液相色谱法鉴别对氯苯胺及其同分异构体

采用高效液相色谱法对纺织品禁用芳香胺对氯苯胺及其同分异构体的鉴别进行了研究。以Inertsil ODS-SP C18(5μm 4.6×250 mm)为色谱柱,甲醇-KH2PO4为流动相进行等度洗脱,检测波长233 nm。该方法简便快捷,有效地解决了纺织品禁用偶氮染料中对氯苯胺假阳性的测试问题。     

纺织品中偶氮染料的测定

本文以柠檬酸盐缓冲溶液(pH=6．0)为介质，用连二亚硫酸钠还原分解纺织品中偶氮染料以产生可能存在的违禁芳香胺，用气相色谱／质谱联用仪测定了纯棉染色布中存在的偶氮染料，该试样中含有联苯胺，其方法回收率为80．6％。     

基于GC-MS测定白酒中氨基甲酸乙酯的探讨

氨基甲酸乙酯是可以危害人类健康的物质,各类酒中均不同程度的微量存在,在一些国家对酒中的含量有明确的限制规定。GB 5009.223-2014《食品安全国家标准食品中氨基甲酸乙酯的测定气相色谱-质谱联用法》规定了相关酒中氨基甲酸乙酯含量测定方法,从方法的专属性、精密度和回收率等几个指标对白酒中氨基甲酸乙酯测定方法进行验证,结果表明此方法在化验室用于白酒中氨基甲酸乙酯的测定是适宜和可靠的。     

马肉中脂肪酸组成及含量的气相色谱-质谱法分析

采用气相色谱-质谱法分析了马肉中脂肪酸的化学组成及各成分的含量。马肉中的脂肪经正己烷提取、硫酸-甲醇酯化法甲酯化、GC-MS测定、总离子流图峰面积归一化法测定各组分相对含量。马肉中饱和脂肪酸含量为38.4%,不饱和脂肪酸为61.6%,其中单不饱和脂肪酸为44.8%;马肉脂肪酸中油酸含量最高,其它由高到低依次为棕榈酸、亚麻酸、棕榈油酸、亚油酸、硬脂酸、肉豆蔻酸、花生四烯酸。结果表明,马肉中脂肪酸能较好地满足人体的营养需求。     

Thiol Derivatization for LC-MS Identification of Microcystins in Complex Matrices

Microcystins are a group of cyclic heptapeptides originating from cyanobacteria. Cyanobacteria also produce a range of peptides and other compounds that can result in complex chromatograms when samples are analyzed by LC-MS. Derivatization with appropriate thiols (e.g., mercaptoethanol) of the olefin in the α,β-unsaturated amide present in most microcystins was shown to simplify analysis of LC-MS chromatograms of sample extracts, making it much easier to identify peaks corresponding to candidate microcystins. Furthermore, interpretation of MS(2) spectra was facilitated by addition of the mass associated with the thiol to the α,β-unsaturated amide of microcystins. Cyanotoxins containing Mdha or Dha reacted readily with thiols, whereas Mser, Ser, Mdhb, and thiol-derivatives of Mdha or Dha did not react under the conditions used. This approach therefore provides a convenient LC-MS method to obtain evidence for the presence of Mdha or Dha and can likely be used to differentiate between the isobaric amino acids Mdha and Dhb in candidate cyanotoxin peaks. When O-(2-mercaptoethyl)-O'-methyl-hexa(ethylene glycol) (MEMHEG) (M(w)t. 356) was used as the thiol, the resulting derivatives eluted in an LC-MS mass window that was largely free of interferences. This approach simplifies detection of candidate microcystin analogues even in the presence of complex mixtures of coeluting components. The method was used for qualitative analysis of a Microcystis aeruginosa culture from Lake Naivasha, Kenya, and the results were verified using precursor-ion scanning and high-resolution mass spectrometry.     

Identification of Geometrical Isomers and Comparison of Different Isomeric Samples of Astaxanthin

Abstract: A high‐performance liquid chromatographic (HPLC) analysis system for isomeric astaxanthin was developed. The separation system consisted of a C₃₀ column and an elution system of methanol/MTBE/water/dichloromethane (77 : 13 : 8 : 2, v/v/v/v). Using the combination of HPLC diode array detector and HPLC atmospheric pressure chemical ionization mass spectrometry, 11 geometrical isomers and 4 epoxides of astaxanthin were successfully identified. Referred to crystal, only isomerization with different degrees was found for solvent dissolving and iodine catalysis, while melting of astaxanthin caused isomerization, slight oxidation, and more noticeable polymerization confirmed by gel permeation chromatography. Chemical changes in isomeric samples all caused a decrease in UV content. The vibrational spectra (infrared and Raman) showed that epoxide was the only new functional group generated for melting. Changes of several key bands and formations of new bands were found in iodine catalysis and melting samples because of isomerization. Practical Application: Eleven geometrical isomers and 4 epoxides, which were normally generated for solvent dissolving, iodine catalysis, and melting of astaxanthin, have been identified by C₃₀‐HPLC‐MS technology. Furthermore, different samples were measured by gel permeation chromatography, UV, infrared, and Raman, based on the analysis of messages, the effect of each processing was well understood.     

假钞的公众识别方法

一、假钞公众识别的必要性马克思在《资本论》中有一段名言：“一旦有适当的利润，资本就胆大起来。如果有10%的利润，它就保证到处使用。有20%的利润，它就活跃起来。有50%的利润，它就铤而走险。为了100%的利润，它就敢践踏一切人间法律。有300%的利润，它就敢犯任何罪行，甚至冒着绞首的危险。”伪造货币“创造”的利润之巨不言而喻，而其危害性也人所共知。轻者给个人造成损失，特别是经济损失。重者扰乱金融秩序，影响社会的稳定。在世界范围内，所有国家都将伪造货币视为严重犯罪，对伪造者处以极刑。对普通大众而言，了解假钞的公众…     

常见皮鞋制作原料与材质鉴定技术

从材质鉴定的角度出发,介绍了市场上可用于皮鞋制作的各类原材料,描述了当前皮鞋市场存在的主要"假冒伪劣"现象,并针对各种不法现象的特殊性,分析了皮鞋材质常用鉴定方法的优缺点及各自存在的问题。最后,预测出一种通用的、对未知材质的皮鞋样品进行鉴定的方法与程序。     

两种柱前衍生RP-HPLC法测定酱腌菜中生物胺的比较

本研究分别采用4-氟-3-硝基三氟甲苯(FNBT)柱前衍生RP-HPLC紫外检测分析方法(简称FNBT衍生法)和丹磺酰氯柱前衍生RP-HPLC紫外检测分析方法(简称DNS-Cl衍生法)测定酱腌菜中生物胺含量,并比较这两种方法对酱腌菜中8种生物胺(组胺、色胺、β-苯乙胺、腐胺、酪胺、尸胺、亚精胺及精胺)检测的差异。结果表明,在浓度范围1~100mg/L内,两种方法对8种生物胺的检测呈现良好的线性相关性,相关系数R~2均大于0.999,FNBT衍生法的检出限(0.016~0.071mg/L)优于DNS-Cl衍生法(0.066~0.191 mg/L)。方法的精确度试验表明:FNBT衍生法的加标平均回收率(92.87%~100.18%)略优于DNS-Cl衍生法的加标平均回收率(83.52%~102.33%),两种方法的测量精密度RSD%均小于5%。DNS-Cl衍生法衍生试剂消耗大、操作繁琐,对生物胺检测的灵敏度低,而FNBT衍生法衍生试剂消耗少、操作简便、快速、灵敏度及准确性更高,适用于大批量食品中微量生物胺的快速、准确分析。用两种方法检测酱腌菜中8种生物胺的含量存在显著差异(p0.05)。     

C30-HPLC-PDA分离与鉴定β,β-胡萝卜素几何异构体

在装备了二极管阵列(PDA)检测器的HPLC上,应用C30固定相,β,β-胡萝卜素的几何异构体获得了良好的分离。分离条件为:固定相=YMCCarotenoidS-5(4.6×250mm)柱;流动相A=乙腈:甲醇:三乙胺(75:25:0.05,V/V);流动相B=甲基叔丁基醚(MTBE)-三乙胺(100:0.05,V/V);线性梯度:B在20min内由0%增至80%;流速=1.0ml/min;PDA波长范围=260～700nm;进样量=20μl。根据各组分的色谱行为、光谱特征和在碘催化下发生几何异构的产物分析,13,13’-、11,11’-、9,9’-顺式和全反式异构体被鉴定。本项研究的结果奠定了应用C30-HPLC-PDA定量检测β,β-胡萝卜素的几何异构体的基础。     

Derivatization of fatty acids and its application for conjugated linoleic acid studies in ruminant meat lipids

Conjugated linoleic acid (c9, t11 CLA) is a dietary fatty acid produced mainly by ruminant animals and exhibits promising health‐promoting biological effects. For lipid fatty acid composition analyses, including CLA, lipids must be pre‐treated so that the free and esterified fatty acids (triacylglycerols, phospholipids, etc) are available for determination. The most common treatments involve fatty acid methyl ester derivatives from relatively simple chemical reactions, but this becomes complicated when esterification of CLA is involved because of potential changes in its positional and geometrical isomers by reaction with certain reagents. In this review we explain concisely the advantages and disadvantages of the most popular methods (acid‐ and base‐catalysed methods) generally employed for total fatty acid derivatization and their determination on a gas chromatograph. Based on our experiences we put forward the (trimethylsilyl)diazomethane method as an alternative and successful approach for ruminant tissue lipid determinations. Copyright © 2005 Society of Chemical Industry     

胶原蛋白的高效制备及与明胶的鉴别

在分析酸提取法和酶解法提取牛皮中胶原蛋白各自的优缺点后,研究并最终确定了一种提取牛皮中胶原蛋白的新方法--酸酶复合法,该法工艺简单,在相对较短的制备时间内,胶原蛋白的提取率可以达到54.5%,同时又保证了胶原蛋白的天然三螺旋结构。同时以对胶原蛋白性质的研究结果为基础,建立一种快速且准确的胶原蛋白和明胶的鉴定及质量评价方法--快速鉴定评价法,包括聚丙烯酰胺凝胶电泳、丹宁酸沉淀实验、胰蛋白酶敏感性实验和体外成纤维能力实验。酸酶复合法和快速鉴定评价法对胶原蛋白提取工艺的大规模生产应用及对市场上各种产品的鉴定及品质评价具有实际意义。     

皮革鉴定的方法与展望

简述了目前动物皮革与人工皮革的鉴定方法和特点,并展望了更加科学的简便有效鉴定新技术.     

红曲及洛伐他汀的生理活性和测定方法研究进展

综述了红曲霉及其发酵产物的研究概况。介绍了红曲霉主要生理活性物质洛伐他汀的作用机理和检测方法的研究进展。