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。     

离子色谱法快速测定白酒中多种有机酸和阴离子

建立了梯度淋洗离子色谱法测定白酒中26种有机酸和阴离子的方法,研究了色谱柱、流速、pH值、淋洗液浓度等实验影响因素,确定了适于26种组分测定的多级梯度淋洗条件。结果表明,当流速为1.00 mL/min,pH值为5.2～6.5时,26种组分在0.02～2.00 mg/L质量浓度范围内具有良好的线性关系（R值均＞0.99）。除了苯甲酸外,25种组分检出限（S/N=3）在0.000 11～0.072 80 mg/L;在0.50 mg/L、1.00 mg/L、2.00 mg/L三个添加浓度水平下,回收率为73.50%～115.13%,精密度实验结果相对标准偏差（RSD）为3.38%～4.97%。     

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。     

离子色谱-脉冲积分安培法同时测定甘薯中10种可溶性糖组分

为建立离子色谱-脉冲积分安培法(IC-PAD)同时检测提取液中10种可溶性糖组分(葡萄糖、果糖、半乳糖、甘露糖、鼠李糖、阿拉伯糖、蔗糖、麦芽糖、棉子糖和水苏糖)的方法,通过80%乙醇水溶液低温超声振荡对甘薯粉样品进行提取,以Thermo Dionex Carbo Pac PA20(3 mm×150 mm)阴离子交换色谱柱为分析柱,以Carbo Pac PA20(3 mm×50 mm)为保护柱,以不同浓度的NaOH、CH3COONa组合淋洗液进行梯度淋洗分离,柱温30 ℃,进样体积10 μL,采用离子色谱-脉冲积分安培方法检测。结果表明:6种单糖线性范围0.02～10 mg/L,其它4种糖线性范围为0.02～20 mg/L,10种糖组分加标回收率94.5%～106.5%,相对标准偏差0.57%～1.89%。本方法线性范围广、操作简单、分析速度快、灵敏度高,重现性好,可用于对甘薯提取液中多种可溶性糖组分的同时测定。利用本方法对实际样品的测定结果表明,不同干燥方式对甘薯可溶性糖含量的影响不同,与冷冻干燥相比,热风干燥增加了甘薯样品中可溶性糖含量,还促进了其它糖分转化生成棉子糖和水苏糖两种功能性低聚糖。     

离子色谱法-积分安培检测器测定葡萄酒中的天然糖

建立测定葡萄酒中常见的8 种天然糖（阿拉伯糖、葡萄糖、木糖、果糖、L-山梨糖、蔗糖、异麦芽酮糖和麦芽糖）的离子色谱分析方法。以淋洗液发生器电解产生的KOH溶液梯度淋洗,在CarboPac PA20高效阴离子交换柱上,8 种天然糖可以在30 min内完成分离。使用积分安培检测器进行测定,8 种糖的检出限（进样量10 μL,RSN=3）分别为0.007、0.004、0.005、0.005、0.003、0.014、0.016 mg/L和0.020 mg/L,且均具有较宽的线性范围（0.06～30 mg/L）。样品测定的相对标准偏差在4.9%～8.7%之间,8 种糖的加标回收率在81.5%～95.1%之间;本方法检测糖简便快捷、分离效果好、无需衍生、灵敏度高,适用于葡萄酒中的8 种常见天然糖组分的分析。     

离子色谱法同时测定啤酒中23种糖、糖醇及醇

建立了积分脉冲安培检测（IPAD）-离子色谱（IC）法同时测定啤酒中23种糖、糖醇及醇的方法,通过对流速、色谱柱温度、淋洗浓度等实验影响因素的考察,探索出了适合23种组分测定的色谱分析条件。结果表明,当流速为0.45 mL/min,淋洗浓度为480 mmol/L,柱温在29 ℃时,23种组分在各自质量浓度范围内具有良好的线性关系（R2＞0.999）。除了甲醇和乙醇外,其他21种组分检出限（LODs）在0.011～0.197 mg/L之间;在0.20 mg/L、1.00 mg/L、2.00 mg/L三个质量浓度添加水平下,23种组分的平均回收率为81.27%～106.12%,精密度试验结果相对标准偏差（RSD）为1.53%～10.52%。该方法高效、灵敏、准确,适于啤酒中23种糖、糖醇及醇的分析测定。     

离子色谱法同时测定葡萄酒中26种有机酸和阴离子

建立了电导抑制-梯度淋洗离子色谱法测定葡萄酒中26种有机酸和阴离子的方法,通过对色谱柱、流速、p H值、淋洗液浓度等实验影响因素的考察,探索出了适合26种组分测定的多级梯度淋洗条件。结果表明,当流速为1.00 m L/min,p H值在5.3~6.0时,26种组分在0.01~1.00 mg/L浓度范围内具有良好的线性关系(0.99)。除了苯甲酸外,25种组分检出限(S/N=3)在0.00009~0.0783 mg/L之间;在0.10 mg/L、0.20 mg/L、1.00 mg/L 3个添加浓度水平下,回收率为75.97%~109.80%,RSD在0.22%~8.38%范围内。     

高效液相色谱同时测定植物饮料中7种植物毒素

建立了同时检测植物饮料中原百部碱、香豆素、黄连素、山道年、细辛脑、长叶薄荷酮和芦荟苷A 7种植物毒素含量的高效液相色谱法。试样经HLB固相萃柱富集净化,甲醇洗脱,氮吹浓缩后用流动相起始梯度定容至1.0 mL,经Welch Ultimate XB-C18色谱柱（4.6 mm×150 mm,5 μm）分离,以甲醇-10 mmol/L乙酸铵水溶液（pH=3）为流动相梯度洗脱,通过紫外检测器进行检测。7种植物毒素化合物在0.20～100.00 mg/L范围内线性关系良好,相关系数均＞0.99,方法的检出限分别为0.2～6.5 μg/kg,定量限为0.8～21.6 μg/kg。分别对3种植物饮料样品进行加标回收率实验,回收率为67.1%～104.0%,相对标准偏差（n=6）为1.08%～5.12%。该方法操作简单,具有较高的准确度和精密度,适用于植物饮料中7种植物毒素含量的检测。     

离子色谱串联MSQ质谱法测定饲料中的亚硝酸盐

建立了一种测定饲料中亚硝酸盐的离子色谱串联MSQ质谱的分析方法。样品经超声提取后,过Ag柱、Na柱、RP柱除杂质,以AS20 2×250 mm色谱柱分离,用氢氧化钾淋洗液发生器自动淋洗,采用梯度淋洗方式,电导检测器定量,质谱定性。结果表明：方法检出限为0.2 mg/kg,标准品在0.02～ 5.00 mg/kg内呈良好线性关系,相关系数为0.999 7,加标回收率为81.0%～ 102.0%。     

柱前衍生-高效液相色谱法检测运动型饮料中γ-氨基丁酸的含量

该研究建立了一种测定运动饮料中γ-氨基丁酸（GABA）的柱前衍生-高效液相色谱（HPLC）方法。 结果表明,样品由乙腈萃 取后,上清液经邻苯二甲醛（OPA）于45 ℃条件下在线柱前衍生2.0 min后进行HPLC检测。 色谱条件：Waters sunfire C18为色谱柱,以 20 mmol/L的乙酸钠溶液-乙腈（体积比70∶30）为流动相,二极管阵列检测器（DAD）的波长为247 nm,柱温30 ℃,流速1.0 mL/min, 进样量20 μL,外标法定量。 γ-氨基丁酸在1.0～100.0 μg/mL质量浓度范围内线性关系良好（R2=0.998 6）,检出限为0.30 mg/kg,定量 限为1.0 mg/kg,加标回收率为82.5%～90.6%,相对标准偏差（RSD）为2.9%～3.7%。 采用该方法检测出5种运动型饮品中GABA含量 在0.32～16.38 mg/100 mL范围内。 该方法具有操作简单、专属性强、灵敏度高等优点,可满足运动型饮料中γ-氨基丁酸的检测要求。     

Matrix effect during the application of a rapid method using HS-SPME followed by GC–ECD for the analysis of 2,4,6-TCA in wine and cork soaks

An off-flavor in wine known as ‘cork taint’ is of concern in the wine and cork industry. Cork taint imparts a musty flavor to the wine and is primarily due to the presence of 2,4,6-trichloroanisole [2,4,6-TCA] in cork stoppers. During this study, an instrumental method for 2,4,6-TCA analysis was developed and evaluated using headspace solid-phase microextraction (HS-SPME) and gas chromatography coupled with an electron capture detector (GC–ECD). 2,3,6-Trichlorotoluene [2,3,6-TCT] was assayed as the internal standard. The method was developed in synthetic wine and was applied in commercial wine samples, as well as in cork soaks obtained by the extraction of TCA from cork stoppers and cork barks using synthetic wine. The method performance was evaluated through the estimation of its linearity (R² > 0.99), repeatability (RSD value = 5.72%) and sensitivity (recovery > 86%, LOD = 0.177–0.368 ng/L) in different types of samples. Due to the complexity of the samples used, the study has been especially focused on the matrix effects that were identified causing significant bias to the quantitative analysis of 2,4,6-TCA in cork soaks, where there is a lack of previous studies.     

超声波辅助-顶空固相微萃取-气相色谱法测定葡萄酒中痕量2,4,6-三氯苯甲醚

建立了超声波-顶空固相微萃取-气相色谱检测葡萄酒中的痕量木塞污染物——2,4,6-三氯苯甲醚（TCA）的方法。试验结果表明,该方法有良好的线性关系,相关系数为0.999 89,方法定量限为0.5 ng/L,相对标准偏差RSD在1.98%～5.32%之间,加标回收率为89.0%～103.2%。该方法操作简便、快速、准确度高、重现性好,适用于普通实验室对葡萄酒中痕量TCA残留的检测。     

Determination of Chloroanisoles and Chlorophenols in Cork and Wine by using HS‐SPME and GC‐ECD Detection

Cork taint is an off‐flavor problem in wine, the main reason being the presence of 2,4,6‐trichloroanisole (TCA) in the cork stopper. In addition to the TCA, the presence of other chloroanisole and chlorophenol family compounds (the perception limits of which are very low) can also result in, or contribute to, cork taint problem. In this study, the levels of 2,4‐dichloroanisole (DCA), 2,4,6‐trichloroanisole (TCA), 2,3,4,6‐tetrachloroanisole (TeCA), pentachloroanisole (PCA), 2,4,6‐trichlorophenol (TCP), 2,3,4,6‐tetrachlorophenol (TeCP) and penthaclorophenol (PCP) were assayed in cork stoppers (natural, agglomerated and colmate) and in red wine samples from different wineries in Turkey using HS‐SPME and GC‐ECD detection. The performance parameters for all chloroanisole and chlorophenol compounds were as follows: recovery 92.48–102.53%, R 0.992‐0.996. The LOQ values were DCA (8.4 ng/L), TCA (0.8 ng/L), TeCa (0.6 ng/L), PCP (0.8 ng/L), TCP (0.8 ng/L), TeCP (1.2 ng/L), and PCP (1.1 ng/L) respectively. In cork stoppers, the amounts of 2,4,6 TCA ranged between 5.4–130.6 ng/g. The 2,3,4,6 TeCA ranged between 1.12‐8.2 ng/g and the PCA ranged between nd (not detected)‐11.01 ng/g. In the wine samples, 2,4,6 TCA ranged between 1.42–70.2 ng/L. The 2,3,4,6 TeCA ranged between nd‐15.1 ng/L and the PCA ranged from nd‐5.16 ng/L. The results indicated that there was a significant correlation between the TCA in wines and the TCA in cork stoppers.     

Determination of geosmin and 2,4,6-trichloroanisole in white and red Austrian wines by headspace SPME-GC/MS and comparison with sensory analysis

This paper describes the development and application of a fast and simple headspace solid phase microextraction GC–MS method for simultaneous determination of geosmin and 2,4,6-trichloroanisole (2,4,6-TCA), two main contributors to off-flavors in wine. The compounds were adsorbed onto a polydimethoxysiloxane (PDMS) fiber at 35 °C for 40 min without prior equilibration, thermally desorbed and analyzed by GC–MS in the selected ion monitoring mode. The parameters for adsorption onto and desorption from the fiber were optimized. This method was applied to analysis of 118 Austrian white and red wines, which were also characterized by sensory analysis. Geosmin was above the limit of detection (0.5 ng/L) in 110 wines (93%) and additionally quantified (>2 ng/L) in 65 wines (55%). It could be detected in wines of each off-flavor (moldy, corky, damp, musty, rotten, woody, grassy) in concentrations up to 16.7 ng/L and even in 90% of the sensorially faultless wines (up to 6.5 ng/L). On the other hand, 2,4,6-trichloroanisole was detected only in 24 wines (20% of all investigated wines) and above the limit of quantitation (2 ng/L) only in 5 wines (4%) sensorially classified as corky; corky and moldy plus other defects; or faultless in concentrations up to 14.3 ng/L. These results show that geosmin is more prevalent than 2,4,6-TCA and that chemical analysis is required especially when other wine characteristic flavors cover beginning off-flavors.     

Development and evaluation of alternative processes for sterilization and deodorization of cork barks and natural cork stoppers

Cork taint, one of the most known off-flavours in wine, is usually attributed to the presence of the aromatic compound 2,4,6-trichloroanisole (2,4,6-TCA) in cork stoppers made from the bark of the cork oak, Quercus suber. There are many major chemical/biochemical pathways through which 2,4,6-TCA can be formed during cork production. The estimated incidence of cork-tainted wine bottles ranges from 2–to 7%, costing global wine industry approximately US$ 10 billion annually. During this study, a laboratory-scale system was designed and constructed, to efficiently treat cork bark and stopper samples using ozone and/or other sterilizing gases, such as steam, via sequential application of pulsed vacuum–pressure cycles. The developed physicochemical processes were studied and evaluated in order to achieve both sterilization conditions and 2,4,6-TCA removal without affecting the mechanical and bottling properties of cork. According to the results, the application of ozone alone seems to be a promising treatment method for cork barks. However, the pulsed treatment ensures both sufficient removal (99%) of both bacteria and moulds from cork stoppers when combined with ozone or steam and satisfactory deodorization of cork stoppers achieving high percentages (90%) of 2,4,6-TCA removal when combined with steam. The operating cost of each alternative process (plain or pulsed, with or without ozone and/or steam) was estimated and compared, in laboratory scale, for the selection of the most efficient process, taking into account technicoeconomical aspects.     

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。     

Presence of cork-taint responsible compounds in wines and their cork stoppers

 Chloroanisoles [2,4-dichloroanisole, 2,4,6-trichloroanisole (TCA), 2,3,4,6-tetrachloroanisole and pentachloroanisole], chlorophenols [2,4,6-trichlorophenol, 2,3,4,6-tetrachlorophenol and pentachlorophenol (PCP)] and guaiacol were detected in red and white cork-tainted bottled wines. These compounds were also found in the cork stoppers from those bottles. A significant correlation was found between TCA in wines and TCA in cork stoppers, and between TCA in wine and intensity of cork taint. At low levels of TCA, the presence of guaiacol or PCP were also found to influence in cork taint. Received: 29 November 1999     

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.     

Cork-borne bacteria and yeasts as potential producers of off-flavours in wine

Bacteria and yeasts were found to be present within cork lenticels, covered by mucous or fibrous substances. They survived heating, peroxide treatment and contact with the alcohol and sulfur dioxide of wine. 187 bacteria and 36 yeast strains were isolated from cork stoppers of wine bottles and, during various stages of production, from corkwood and new cork stoppers. After culturing, a number of isolates showed the ability to modify the aroma of model systems consisting of dilute or full strength wine and pulverised cork. The aromas produced by isolates of varying cork origin are tabled. A small number of isolates methylated 2,4,6-trichlorophenol, yielding 2,4,6-trichloroanisole, responsible for the typical cork taint. During the boiling of cork slabs, the internal temperature on the inside of a box made from cork slices did not exceed 87°C.     

Screening of musty-earthy compounds from tainted cork using water-based soaks followed by headspace solid-phase microextraction and gas chromatography–mass spectrometry

Compounds responsible for musty-earthy off-flavours in cork, namely 2-methylisoborneol (MIB), geosmin (GSM), 2,4,6-trichloroanisole (TCA) and 2-methoxy-3-isopropylpyrazine (IPMP), were determined from tainted cork using water-based soaks followed by headspace solid-phase microextraction and gas chromatography–mass spectrometry (HS-SPME–GC–MS). The influence of the fibre coating used and of the extraction time and temperature were investigated for the joint analysis of MIB, GSM, TCA and IPMP. Considering the obtained results, an extraction time of 30 min at a temperature of 50 °C were fixed as experimental conditions, using a divinylbenzene/carboxen-polydimethylsiloxane/polydimethylsiloxane (DVB/CAR/PDMS) fibre. Quality parameters of the chromatographic method were obtained and good recoveries (117–128%) were found in spiked aqueous cork macerates. Using the same experimental conditions, the presence of guaiacol, 2,3,4,6-tetrachloroanisole (TeCA), pentachloroanisole (PCA), 2,4,6-tribromoanisole (TBA) and 2-methoxy-3,5-dimethylpyrazine (MDMP) could also be evaluated in a single chromatogram. From all the compounds analyzed in tainted samples, TCA and guaiacol were the only contaminants present and only TCA concentrations were found above its perception threshold in water.