分光光度法测定葡萄酒中尿素含量

目的:建立了分光光度法定量检测葡萄酒中尿素含量的方法。方法:采用强阳性离子交换树脂柱对葡萄酒中尿素进行分离,依据费伦反应原理,采用分光光度法测定洗脱液中尿素含量。结果:建立方法的最佳参数为丁二酮单肟最佳添加量6.0g/L,氨基硫脲最佳添加量0.10g/L,反应中煮沸时间为5min,用分光光度计在530nm波长下测定吸光度。方法的最低检出限0.5mg/L,相对标准偏差为3.1%～4.4%,回收率为92.8%～103.1%。结论:此方法简便快速、准确可靠,适合用于葡萄酒样品中尿素含量的定量检测。     

分光光度法检测葡萄酒中花青素方法可行性分析

目的 分析分光光度法检测葡萄酒中花青素方法的可行性,并对方法进行优化。方法 通过分析标准品和样品的全波长扫描图,确定分光光度法的最佳检测波长;通过检测不同储存时间时标准品吸光值,分析标准品稳定性,确定标准品储备液最佳使用时间;通过检测加标回收率、检出限、定量限等参数,同时做与液相色谱法的数据对比,分析该方法的稳定性和准确性。 结果 最佳检测波长为518 nm;标准品母液在2 d内吸光值比较稳定;线性范围为1~20 μg/mL时,r2为0.9998,检出限为0.188 mg/100 mL,定量限为0.625 mg/100 mL。加标水平为4、8、12 mg/100 mL时,加标回收率为102.3%~106.5%。分光光度法检测葡萄酒样品中花青素含量为(6.58±0.38) mg/100 mL,液相法检测样品中总花青素含量为(6.84±0.021) mg/100 mL。结论 分光光度法适合用于葡萄酒中花青素含量的检测,方法准确性较好。     

百里酚分光光度法测定发酵液中L-精氨酸含量

目的建立定量检测发酵液中L-精氨酸含量的方法.方法以百里酚的次溴酸钠溶液为显色剂,用分光光度计比色测定.结果百里酚分光光度法检测L-精氨酸的最佳条件为样品稀释液5.0 mL,依次加入0.03%百里酚溶液2.0 mL,0.7%次溴酸钠溶液1.0 mL,摇匀,30 s内加入40%尿素溶液1.0 mL,冰水浴中显色2 min,测定OD470nm.该方法的检出限为2.0 μg/mL,摩尔吸光系数ε为6.8×103L/(mol·cm),回收率98.8%～101.2%,发酵液样品测定的相对标准偏差0.23%～0.59%.结论该方法简便、快速、准确可靠,适合用于发酵液中L-精氨酸含量的定量检测.     

分光光度法快速检测青方腐乳中的硫化钠含量

目的 建立分光光度法快速检测青方腐乳制品中硫化物（以Na2S计）的方法。方法 通过比较乙酸铅标准溶液反应前后的吸光度差值计算出消耗的乙酸铅量,换算得到样品中硫化钠的含量,以此间接检测方法判断样品中硫化物的添加情况。结果 在干扰离子浓度为0.1 mol/L的条件下,经掩蔽剂去除后加标回收率均提高到88.45%~91.73%,相对标准偏差为0.28%~1.74%。乙酸铅分光光度检测结果在1~5 mg/kg范围内满足要求,相关系数大于0.999。测定硫化钠的方法定量限为6.0 mg/L。结论 该方法操作简便快速,稳定性好、专属性强,仪器设备需求简单,适用于青方腐乳中非法使用硫化钠的快速检测。     

乙酰丙酮分光光度法测定白菜中甲醛含量的方法优化及其在快检结果验证中的应用

目的建立乙酰丙酮分光光度法测定白菜中甲醛含量的方法,并用此方法验证甲醛速测盒的检测结果。方法以甲醛含量为指标,研究样品浸泡时间、加蒸馏水量、加磷酸量、蒸馏时间等前处理条件和显色时间、水浴时间、加乙酰丙酮量等测定条件对白菜中甲醛测定结果的影响。以大白菜为试样,对比乙酰丙酮分光光度法和甲醛速测盒的检测结果。结果白菜中甲醛含量测定的最佳的条件为样品浸泡时间35 min,加水量160 m L,磷酸添加量5 m L,蒸馏时间80 min,乙酰丙酮添加量1 m L,水浴时间5 min,显色时间15 min。在此条件下,白菜中甲醛回收率为95.2%～99.7%。甲醛速测盒的结果与之比对,结果一致。结论乙酰丙酮分光光度法结果准确,适合用于大白菜中甲醛的测定,实验中所用甲醛速测盒与之结果一致,可以快速有效测定白菜中甲醛含量。     

液相色谱-质谱法和高效液相色谱法定性定量测定籽瓜中的L-瓜氨酸

建立一种非衍生化样品前处理的液相色谱-质谱和高效液相色谱方法,对籽瓜中的L-瓜氨酸进行定性、定量分析,通过单因素试验和正交试验优化提取条件。液相色谱-质谱条件：Acuity C18（50 mm×2.1 mm,1.7 μm）色谱柱;流动相：10%乙腈和90%甲醇溶液（甲醇-水体积比1∶1）;流速0.2 mL/min;柱温：40 ℃;进
样量10 μL。在电喷雾离子源正模式、多反应监测扫描方式下分析,L-瓜氨酸的定性离子对为m/z 176.09/158.9,m/z 176.09/112.9,定量离子对为m/z 176.09/158.9。高效液相色谱条件：Platisil ODS C18 （250 mm×4.6 mm,5 μm）色谱柱,以0.03 mmol/L磷酸为流动相,流速0.7 mL/min,柱温30 ℃,检测波长202 nm。结果表明：L-瓜氨酸标准品在0.5～100 μg/mL范围内线性关系良好（R2=0.999 9）,平均回收率在95.12%～104.21%之间,相对标准偏差为1.86%～4.75%（n=3）。籽瓜中含有丰富的L-瓜氨酸,本方法测得籽瓜样品中L-瓜氨酸的平均含量为0.656～2.563 mg/g。     

盐辅助分散液液微萃取-气相色谱-串联质谱法检测葡萄酒中的氨基甲酸乙酯

目的建立了盐辅助分散液液微萃取(salt-assisted dispersive liquid-liquid microextraction,SADLLME),稳定同位素稀释,气相色谱-串联质谱法(gas chromatography-tandem mass spectrometry,GC-MS/MS)检测葡萄酒中氨基甲酸乙酯(ethyl carbamate,EC)的方法。方法取30 mL葡萄酒于50 mL离心管中,加入浓度为10μg/mL的EC-d5溶液100μL和硫酸钠3 g,震荡溶解,注射针快速打入700μL二氯甲烷,震荡1 min,离心,取下层有机相,经DB-INNWAX UI色谱柱(30 m×0.25 mm,0.25μm)分离,多重反应监测方式进行质谱检测。结果方法在验证浓度范围内(5～1500 ng/mL),线性良好,r~2=0.9988,检出限为0.73μg/L,定量限为2.18μg/L,回收率为91.5%～97.8%,相对标准偏差为2.55%～5.26%。对市场上3个品牌红葡萄酒进行检测,EC含量为6.82～15.3μg/L。结论该方法样品处理简便、快速,相对绿色,定性、定量可靠,能够满足葡萄酒中EC风险监测的需要。     

高效液相色谱法测定黄酒中瓜氨酸的含量

为建立高效液相色谱测定黄酒中瓜氨酸含量的方法,采用OPA为柱前衍生剂,醋酸钠-乙腈-甲醇-水混合体系梯度洗脱,流速为2.0 mL/min,DAD检测波长为UV-338 nm。在10～200 mg/L范围其浓度与响应值具有良好的线性关系,相关系数大于0.999,相对标准偏差0.153%～0.921%,回收率98.44.70%～100.81%;检出限为1.048 mg/L,定量检出限为3.460 mg/L。广东客家娘酒中瓜氨酸的含量58.84～80.83 mg/L,江浙黄酒中瓜氨酸的含量162.61～178.26 mg/L。     

微量、快速测定葡萄与葡萄酒总酚

基于Folin-Ciocalteu 分光光度法的原理,借助微量移液器和微波处理,通过优化反应条件,建立一种新的微量、快速测定葡萄与葡萄酒总酚含量的方法。实验得到体系的最佳反应条件为0.1mL 测试样品,0.1mL 1mol/LFolin-Ciocalteu 试剂和0.8mL 60g/L Na2CO3 溶液,在微波炉的中档下处理20s 后测定765nm 波长处的吸光度。以没食子酸为标准品作标准曲线,在质量浓度1～50mg/L 范围内与吸光度呈良好线性关系(R2=0.9996)。对葡萄皮与葡萄酒进行加标回收率实验的平均回收率分别为98.1%和97.2%,精密度(n=9)测定相对标准偏差(RSD)分别为1.40%和1 . 0 1%。该方法不但量微、快速,而且操作简便,重复性好,结果精准可靠。     

固相萃取-分光光度法快速检测腐竹中的碱性橙

目的：建立固相萃取净化富集,分光光度法快速检测腐竹中禁用色素碱性橙的方法。方法：样品经甲醇超声提取,C18固相萃取柱萃取,以20%甲醇溶液（V/V）为清洗剂净化,80%甲醇溶液（V/V）为洗脱剂洗脱富集后,用分光光度法进行测定。结果：碱性橙在2.0～10.0μg/mL浓度范围呈现良好的线性关系,相关系数R=0.9955;在2.0～8.0μg/mL添加水平时回收率范围为102.24%～84.15%,重复性实验平均回收率为98.45%,相对标准偏差为1.87%（n=5）。结论：该法灵敏度高、重复性好,操作简便快速,结果准确,适用于腐竹中碱性橙的快速检测。     

Simultaneous determination of ketoacids and dicarbonyl compounds, key Maillard intermediates on the generation of aged wine aroma

ABSTRACT:  The aim of this work was the simultaneous determination of both ketoacids and dicarbonyl compounds in wine. To detect ketoacid compounds in wine, a method based on the quinoxaline derivatives by the reaction with diaminobenzene, currently employed to detect α-dicarbonyl compounds, was developed. The quinoxaline derivatives were detected by RP-HPLC with UV detection, which allows the determination of the major dicarbonyl compounds in wine: glyoxal, methylglyoxal, diacetyl and pentane-2,6-dione, and the quinoxaline/quinoxalinol derivatives of α-keto-γ-(methylthio)butyric acid and β-phenylpyruvic acid (intermediate ketoacid compounds of methional and phenylacetaldehyde) were simultaneously detected by a fluorescence detector. The identification was performed by comparison with standards and also by using LC-MSMS. The levels found in 15 wines analyzed (white wines, Madeira wines, and Port wines) diverge according to the type and the age of the wine. The ketoacid compounds ranged from 0.2 to 5.7 mg/L for α-keto-γ-(methylthio)butyric acid and 0.1 to 9.6 mg/L for β-phenylpyruvic acid. The quantities observed for dicarbonyl compounds were similar to those already reported.     

进口葡萄酒中赭曲霉毒素A的含量分析

为了解进口葡萄酒中赭曲霉毒素A的含量和污染状况,本研究建立了无需净化、浓缩,直接进样,采用液相色谱-串联质谱联用法(LC-MS/MS)测定葡萄酒中赭曲霉毒素A的方法。赭曲霉毒素A空白基质标准溶液在1.0～20.0 ng/mL浓度范围内线性良好,方法检测限达到0.05 ng/mL,添加浓度为2.0 ng/mL质控样品的回收率为98.7%～113.2%,精密度<5.7%。应用该方法测定了84个进口葡萄酒样品中赭曲霉毒素A的含量,结果表明,赭曲霉毒素的检出率为100%,含量为0.14～1.10 ng/mL,平均含量为0.32 ng/mL。     

Wine composition plays an important role in the control of carcinogenic precursor formation by Lactobacillus hilgardii X1B

BACKGROUND: Lactobacillus hilgardii, a wine lactic acid bacterium, is able to use arginine, through the arginine deiminase pathway with the formation of citrulline, a precursor of the carcinogen ethyl carbamate. The influence of different Argentine wine varieties (Merlot, Cabernet Sauvignon and Malbec), on bacterial growth and arginine metabolism was examined. Furthermore, the effect of different components normally present in wines on the enzyme activities of the arginine deiminase system was determined. RESULTS: Malbec wine under all conditions assayed (33, 50 and 100% supplemented wine:basal media) showed higher arginine consumption and citrulline production than the other wines, as well as the highest bacterial growth and survival of Lactobacillus hilgardii X₁B. Glucose and L ‐malic inhibited both arginine deiminase enzymes while fructose and citric acid only inhibited arginine deiminase. The red wines assayed in this study had different composition, and this is an explanation for the different behavior of the bacterium. CONCLUSION: The highest citrulline production in Malbec wine could be correlated with its lower concentrations of glucose, fructose, citric and phenolic acid than the other wines. Therefore, a wine with lower concentration of these sugars and acids could be dangerous due to the formation of ethyl carbamate precursors. Copyright © 2012 Society of Chemical Industry     

樱桃酒中有机酸种类和含量的研究

采用反相高效液相色谱法(RP-HPLC)对樱桃(Prunus avium L.)酒中有机酸的种类和含量进行了研究。采用Atlantis dC18色谱柱(250mm×4.6mm,5μm),以0.02mol/L的KH2PO4溶液(pH值2.80)为流动相,流速为0.70mL/min,柱温30℃,紫外检测器检测波长为210nm。在此色谱条件下,方法重现性好,精密度高,有机酸在浓度(0～9.0)×103mg/L,线性相关系数均大于0.9990,加标回收率为96%～105%,各有机酸检出限≤8.0mg/L。在此条件下测定发酵樱桃酒中的有机酸,得到樱桃酒中主要有机酸是苹果酸,其次是柠檬酸、乳酸、琥珀酸、酒石酸和草酸。     

高效液相色谱法同时测定葡萄酒中16 种添加剂

研究同时测定葡萄酒中16 种添加剂的高效液相色谱方法。该法主要采用C A P C E L L P A K C 18柱（150 mm×4.6 mm,5 μm）分离,以甲醇-20 mmol/L乙酸铵溶液为流动相,采取梯度洗脱,在波长250 nm处进行测定。结果表明,在0.1～20 mg/L的质量浓度范围内线性相关系数良好,相关系数范围为0.999 3～0.999 7,方法检出限范围为0.01～0.5 mg/L,相对标准偏差在0.3%～6.3%之间,平均回收率范围在76.5%～108.5%之间。本方法简便、可靠,能满足对市场上葡萄酒中相关非法添加剂的检测监控要求。     

Determination of ochratoxin A in wines by capillary liquid chromatography with laser induced fluorescence detection using dispersive liquid-liquid microextraction

A method based on reverse phase capillary high performance liquid chromatography (capillary HPLC) coupled to laser-induced fluorescence detection (LIF) has been proposed for the determination of ochratoxin A (OTA) in wine samples. An anionic micellar medium was added to the mobile phase for increasing the fluorescence intensity and peak efficiency. Dispersive liquid-liquid microextraction (DLLME) has been used as a simple and efficient sample pretreatment method for the analysis of OTA in wines, being optimised by means of experimental design. The limit of detection was 5.5 ng L(-1) (3 × S/N) and recoveries for different wines ranged from 91.7 to 98.1%. The proposed methodology could be classified as a green analytical chemistry alternative, combining the low organic solvent volumes required in the DLLME with the reduced consumption of mobile phase in capillary HPLC. The use of LIF as detector provided an extremely sensitive method for the determination of OTA in wines.     

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.     

顶空-气相色谱法测定酒中甲醇

建立了顶空-气相色谱法测定酒中甲醇的分析方法。采用氢火焰离子化检测器,选择DB-624型毛细管色谱柱作为分离柱,程序升温,载气氮气流速为1.5m L/min,分流比为3:1。顶空进样器,顶空瓶加热温度为65℃,平衡时间为25min。结果表明,该方法测得甲醇的质量浓度在59.9~359.4mg/L范围内与峰面积呈线性关系良好,相关系数为0.9995。样品的加标回收率为95.0%~99.2%,最低检出限为0.005g/L。该方法快速、简便,准确度和灵敏度高,适合于酒中甲醇质量浓度的检测。     

固相萃取-高效液相色谱检测葡萄酒中罗丹明B

建立固相萃取富集净化,高效液相色谱紫外检测葡萄酒中禁用色素罗丹明B的方法。葡萄酒样品中的罗丹明B经C18固相萃取,40%乙醇溶液清洗净化,80%的甲醇溶液洗脱后,用高效液相色谱紫外检测器进行测定。结果表明：罗丹明B在1.0～10.0μg/mL范围呈现良好的线性关系,相关系数0.9924;在1.5～3.5μg/mL添加水平时,平均回收率为72.06%,相对标准偏差为2.87%(n=5);定量测出限为0.25μg/mL。表明该方法灵敏度高,重复性良好,操作简便快速,适用于葡萄酒中罗丹明B的检测。     

气相色谱-质谱联用法测定酒类中的甜蜜素

本实验建立了快速测定酒类中甜蜜素的气相色谱-质谱联用方法。酒类中的甜蜜素在酸性条件下,用次氯酸钠将酒中的甜蜜素转化为含环己基氨基的化合物N,N-二氯环己胺,以正己烷萃取,用内标法定量,以气相色谱-质谱联用法测定。结果表明,样品中添加0.500～4.00 mg/L水平的甜蜜素时,回收率范围为92.4%～110.4%,检测限为0.010 mg/L,相对标准偏差范围为4.52%～7.21%。