IC-IPAD同时测定运动饮料中20种氨基酸和6种糖

建立了梯度淋洗-离子色谱-积分脉冲安培检测法同时测定运动饮料中20种氨基酸和6种糖的分析方法。通过对梯度淋洗条件、色谱柱温度、pH以及前处理条件等实验影响因素的考察,优化出适合同时检测26种组分的分析方法。结果表明,样品经调节pH沉淀蛋白后,再由RP净化柱处理,采用多级梯度淋洗模式,在35 ℃的色谱柱温度和样品溶液pH值为5.2～6.7条件下进行分离检测,26种组分在0.5～50.0 mg/L质量浓度范围内线性良好,相关系数（R2）为0.990～0.999,检出限为0.001～0.060 mg/L,定量限为0.003～0.200 mg/L。加标试验分别添加1 mg/L,10 mg/L和50 mg/L 3个水平,加标回收率达到86.2%～105.0%（n=5）,相对标准偏差（RSD）为1.9%～5.3%。该方法高效、简便、灵敏、准确,可用于运动饮料中多种氨基酸和糖的同时测定分析。     

积分脉冲安培检测-离子色谱法同时测定果汁中20种氨基酸

建立了梯度淋洗-积分脉冲安培检测-离子色谱法测定果汁中20种氨基酸的方法,通过对流速、色谱柱温度、pH等实验影响因素的考察,探索出了适合20种组分测定的多级梯度淋洗条件。结果表明,当流速为0.25mL/min,pH在5.5～7.0,柱温为30℃时,20种组分在0.05～2.50 mg/L浓度范围内具有良好的线性关系(R0.995)。除了亮氨酸、异亮氨酸、色氨酸外,其他17种组分检出限均小于0.05mg/L;在0.20、0.50、2.00 mg/L三个添加浓度下,回收率为82.73%～107.39%,RSD在1.97%～8.72%范围内。     

气相色谱-质谱法测定葡萄酒中邻苯二甲酸二丁酯含量的不确定度评定

目的对气相色谱.质谱法测定葡萄酒中邻苯二甲酸二丁酯(DBP)的方法进行不确定度分析。方法依据GB/T 21911-2008《食品中邻苯二甲酸酯的测定》,采用气相色谱.质谱法测定葡萄酒中的邻苯二甲酸二丁酯类增塑剂。参照JJF1059-1999《测量不确定度的评定与表示》,对整个过程中不确定度的来源进行了分析。结果气相色谱-质谱法测定葡萄酒中DBP过程中的扩展不确定为0.01135 mg/kg。结论本方法适用于气相色谱法测定葡萄酒中邻苯二甲酸二丁酯的不确定度评定。     

葡萄酒和软木塞中2,4,6-三氯苯甲醚检测方法的研究进展

本文介绍了葡萄酒和软木塞中2,4,6-三氯苯甲醚（2,4,6-trichloroanisole,TCA）的来源及影响,分析了2,4,6-三氯苯甲醚的检测难点,总结了目前检测2,4,6-三氯苯甲醚方法的总体趋势及现状。按照前处理方法的原理分类,介绍了前处理方法的定义、特点,并概述和讨论了前处理方法在萃取葡萄酒和软木塞中2,4,6-三氯苯甲醚中的应用;根据仪器检测方法的不同特点,总结和讨论了仪器检测方法在分析检测葡萄酒和软木塞中2,4,6-三氯苯甲醚的应用。前处理方法和仪器检测方法相结合,达到了浓缩和检测葡萄酒和软木塞中2,4,6-三氯苯甲醚的目的。     

离子色谱-脉冲安培法同时测定食品中9种糖和糖醇的含量

建立一种同时测定葡萄糖、果糖、蔗糖、麦芽糖、乳糖、赤藓糖醇、木糖醇、山梨糖醇和麦芽糖醇的离子色谱检测技术。对样品的前处理及色谱柱的选择进行优化,最终选择采用调节pH沉淀蛋白,CarboPac PA1色谱柱分离,以氢氧化钠-乙酸钠为淋洗液梯度洗脱,使用脉冲安培检测器进行检测。结果表明,9种糖及糖醇在方法条件下能够完全分离,在0.1~10 μg/mL范围内线性关系良好,方法重复性RSD小于3%,回收率在96.54%~103.71%之间。对市售7款无糖或低糖产品按方法进行检测,无糖样品的含糖量均低于0.5%,低糖样品的含糖量均低于5%。该方法操作简便,灵敏度高,分离度好,能够快速、准确地测定低糖、无糖食品中糖和糖醇的含量。     

气相色谱-质谱法测定柑橘中丙溴磷的不确定度评定

目的建立气相色谱-质谱法(gas chromatography-tandem mass spectrometry, GC-MS/MS)测定柑橘中丙溴磷不确定度的评定模型。方法根据CNAS-GL006:2018《化学分析中不确定度的评估指南》,分析气相色谱-质谱法测定柑橘中丙溴磷的不确定度来源,建立科学的数学模型并量化各个影响分量,得到丙溴磷测定结果的拓展不确定度。结果气相色谱-质谱法测定丙溴磷时,对于结果的不确定度影响顺序为:标准曲线的稀释配制过程线性拟合样品的前处理过程,当柑橘中丙溴磷含量为0.15 mg/kg时,其拓展不确定度为0.04 mg/kg(k=2)。结论该评估模型为气相色谱-质谱法测定丙溴磷,内标法进行定量时的不确定度的评估提供了参考依据。     

离子色谱-脉冲安培检测器分析奶粉中低聚果糖

建立了离子色谱-脉冲安培检测分析奶粉中低聚果糖的方法。采用CarboPacPA200分离柱对分离条件进行了优化,确定柱温为30℃、淋洗液梯度洗脱,在10．0～50．0mg·L^-1范围内低聚果糖呈良好线性,回收率蔗果三糖（GF3）73．1％-82．6％、蔗果四糖（GF4）76．4％-82．9％、蔗果五糖（GF5）73．8％-77．6％,检出限分别为蔗果三糖10mg·kg^-1、蔗果四糖20mg·kg^-1、蔗果五糖24mg·kg～,精密度分别为蔗果三糖3．22％～4．61％、蔗果四糖4．60％-4．94％、蔗果五糖1．82％-3．26％。检测了乳粉中的低聚果糖．效果良好。     

气相色谱-质谱法测定芹菜中甲拌磷残留量的 测量不确定度评定

目的评定气相色谱-质谱法对阳性芹菜样品中甲拌磷残留量测定不确定度。方法参照JJF1135-2005《化学分析测量不确定度评定》和JJF1059.1-2012《测量不确定度评定与表示》,建立气相色谱-质谱法测定芹菜样品中甲拌磷残留量不确定度评定的数学模型,对测定过程中不确定度分量来源进行分析和评定。结果通过对不确定度各分量进行量化和合成,结果表明阳性芹菜样品中甲拌磷的残留量为0.021 mg/kg,扩展不确定度为0.003 mg/kg (k=2)。结论整个测定过程中,标准曲线配制过程所产生的不确定度分量最大,其次为方法重复性和测量重复性产生的分量,这为本实验室内部质量控制提供了依据。     

离子色谱-积分脉冲安培法测定烟草中18种游离氨基酸

采用离子色谱-积分脉冲安培法同时测定了烟草中18种游离氨基酸的含量.结果表明,该方法同时检测烟草中18种游离氨基酸的平均回收率为80%～115%,最低检出限为0.03～0.75 μg/mL,线性相关系数为0.9900～0.9992.该方法成功对比分析测定了烤烟、白肋烟和香料烟3种不同类型单料烟以及国内外不同风格卷烟中18种游离氨基酸的含量.     

Origin and fate of 2,4,6-trichloroanisole in cork bark and wine corks

2,4,6-Trichloroanisole (TCA), which is a major cause of cork taint in bottled wine, is already present in the bark of living cork trees to the extent that it can account for the majority of incidences of cork taint in bottled wine. Other post-harvest sources of TCA are known and may add to the forest-derived TCA in cork. Both the origin of TCA in the bark in the forest, and the means by which additional TCA can accumulate in the corks during manufacture, have been examined. TCA can originate from 2,4,6-trichlorophenol (TCP) produced from naturally-occurring phenol and chlorine from sanitisers and cleaning products, and town water. Also, chlorophenol biocides have accumulated in the environment due to the large quantities used in previous times – TCP has been a minor impurity in pentachlorophenol biocides and a major ingredient in other preparations. There is some evidence that chlorophenols were used in pest management in the forest prior to restrictions on the use of these materials. The factors affecting the uptake and loss of TCA by the bark on the tree and by corks during production, and through to their use in the bottling of wine have been considered in this review.     

Transformation ability of fungi isolated from cork and grape to produce 2,4,6-trichloroanisole from 2,4,6-trichlorophenol

The ability of eight fungal strains to transform 2,4,6-trichlorophenol (TCP) to 2,4,6-trichloroanisole (TCA) was studied. These fungi were isolated from cork, belonging to the genera Penicillium, Aspergillus, Trichoderma and Chrysonilia, and from grapes Botrytis cinerea. All, except Chrysonilia, produced TCA when grown directly on cork in the presence of TCP, Aspergillus and Botrytis cinerea being the ones with the highest level of production. It is the first time that Botrytis cinerea, a microorganism often present on grapes and in winery environments, has been shown to transform TCP into TCA. This result can partially explain the wine cork taint before being bottled.     

Permeation of 2,4,6-trichloroanisole through cork closures in wine bottles

Deuterium-labelled trichloroanisole (d₅-TCA) added to the surface of wine corks in bottles did not contaminate wine after more than three years of bottle storage. Most of the added d₅-TCA was lost, presumably by evaporation. That remaining was largely confined to the outer portion of the closures. Under the conditions of this study, the cork closures were highly effective barriers to the transmission of exogenous TCA.     

优化GC检测2,4,6-三氯苯甲醚的萃取条件

2,4,6-三氯苯甲醚（TCA）的萃取条件直接影响气相色谱技术分析检测结果的准确性。最佳萃取条件为:萃取头涂层聚二甲基硅氧烷-二乙烯基苯（PDMS/DVB）,萃取液体积10m L,平衡时间20min,萃取时间35min,氯化钠含量为30%,萃取温度30℃,搅拌转速40r/s。联合气相色谱电子捕获技术（GC-ECD）和气相色谱质谱联用技术（GC-MS）验证该结果,显示:线性相关系数R2分别为0.9974和0.9998;相对标准偏差RSD分别为1.26%³.85%和0.89%³.00%;回收率:60%⁷2.50%和86%¹01%;最低检出限LOD:0.30×10-12g/L和1.00×10-11g/L;定量限LOQ:1.10×10-12g/L和0.20×10-9g/L。两种仪器均满足检测要求,GC-ECD灵敏度更高,GC-MS定量更精准。      

顶空固相微萃取与气相色谱-电子捕获技术联用检测软木塞中2,4,6-三氯苯甲醚

建立利用顶空固相微萃取与气相色谱电子捕获技术联用分析检测葡萄酒软木塞中2,4,6-三氯苯甲醚含量的方法。该方法测定软木塞中2,4,6-三氯苯甲醚的相关系数（R²）为0.999 9,精密度好（相对标准偏差不大于5.6%）,回收率为101%～108%,检出限为0.20 pg/L、定量限为0.66 pg/L。利用该方法测定了11 种不同类型的软木塞中2,4,6-三氯苯甲醚的含量,证实了所建方法适用于葡萄酒软木塞中痕量2,4,6-三氯苯甲醚含量的测定。     

Transformation ability of fungi isolated from cork and grape to produce 2,4,6-trichloroanisole from 2,4,6-trichlorophenol

The ability of eight fungal strains to transform 2,4,6-trichlorophenol (TCP) to 2,4,6-trichloroanisole (TCA) was studied. These fungi were isolated from cork, belonging to the genera Penicillium, Aspergillus, Trichoderma and Chrysonilia, and from grapes Botrytis cinerea. All, except Chrysonilia, produced TCA when grown directly on cork in the presence of TCP, Aspergillus and Botrytis cinerea being the ones with the highest level of production. It is the first time that Botrytis cinerea, a microorganism often present on grapes and in winery environments, has been shown to transform TCP into TCA. This result can partially explain the wine cork taint before being bottled.     

GC-MS/MS法测定白酒中3种塑化剂含量的不确定度评定

对采用GC-MS/MS法测定白酒中DIBP、DBP和DEHP含量的不确定度进行评定。依据JJF 1135—2005《化学分析测量不确定度评定》和JJF 1059.1—2012《测量不确定度评定与表示》中的有关规定,建立测定白酒中3种塑化剂含量的不确定度数学模型,分析测量不确定度的来源,计算各不确定度分量并进行合成。结果表明,DIBP、DBP和DEHP的扩展不确定度分别为0.060,0.062,0.17mg/kg;不确定度主要来源于标准溶液的配制、测量重复性和标准曲线的拟合。     

Absorption of 2,4,6-trichloroanisole by wine corks via the vapour phase in an enclosed environment

Natural bark corks which were exposed to an atmosphere saturated with deuterium-labelled 2,4,6-trichloroanisole (d₅-TCA) absorbed the d₅-TCA rapidly. A commercially applied surface treatment did not prevent the ingress of the d₅-TCA into the corks. d₅-TCA was lost from contaminated corks by aeration relatively slowly. Nevertheless, the observation that TCA can be desorbed in this manner suggests that aeration, albeit under modified conditions, may yet prove useful in improving the quality of wine corks. Most of the absorbed d₅-TCA was localised in the outer 2 mm of the cork cylinder, but a significant amount migrated to the interior of the cork cylinder after as little as twenty-four hours of exposure. Significantly more d₅-TCA was found in the older growth compared to the younger growth bark after this time.     

顶空固相微萃取联合气相色谱-质谱检测葡萄酒中2,4,6-三氯苯甲醚

利用响应面法优化采用顶空固相微萃取联合气相色谱-质谱技术检测葡萄酒中2,4,6-三氯苯甲醚（2,4,6-trichloroanisole,TCA）。对萃取头进行了选择,并优化固相微萃取参数：样品体积、萃取温度、平衡时间和萃取时间等对TCA萃取效果的影响。结果表明,用聚二甲基硅氧烷/二乙烯基苯（65 μm）萃取头进行TCA萃取的最佳条件：样品9.8 mL、2 g NaCl、33 ℃平衡10 min、萃取90 min进行气相色谱-质谱分析,以TCA-d5为内标物进行定量。该方法的相关系数R2为0.999 9,重复性的相对标准偏差为1.03%,加标回收率范围在95.7%～106.1%之间,检出限和定量限分别为0.3 ng/L和1 ng/L。检测7 种市售葡萄酒产品的TCA含量在0～7.6 ng/L之间,干白葡萄酒中TCA含量低于干红葡萄酒。该方法操作简单、可靠,适用于葡萄酒中TCA的测定。