酱油、酸水解植物蛋白、焦糖色素中乙酰丙酸的测定

对酱油、酸水解植物蛋白（HVP）、焦糖色素中乙酰丙酸的含量进行了测定。其中，酱油中乙酰丙酸含量较低，酸水解植物蛋白中乙酰丙酸含量较多（最高含量为15．79％），而焦糖色素中也测出含有乙酰丙酸（最高含量达8．02％）。故此认为采用乙酰丙酸指标来判定酿造酱油还是配制酱油是不恰当的。     

高效液相色谱法测定酱油及食醋中的苯甲酸和山梨酸

建立了一种用高效液相色谱法快速测定酱油及食醋中苯甲酸和山梨酸的方法.使用的色谱柱为Agillent C18柱,流动相为乙酸胺:甲醇(93:7,v/v),检测波长230nm.苯甲酸和山梨酸标准溶液在2.5mg/L～50mg/L内线性良好,其线性相关系数分别0.9991和0.9984.加标回收率分别为91.7％和98.7％,测量结果的相对标准偏差(RSD)为2.77％和3.55％,苯甲酸和山梨酸的检测限分别为0.90mg/kg和0.85mg/kg.该法简单,快速,具有良好的准确度和灵敏度.     

高效液相色谱法测定酱油中组胺的含量

目的 建立丹磺酰氯柱前衍生-高效液相色谱法测定酱油中组胺含量的方法.方法 样品酱油以1,7-二氨基庚烷作为内标,用正丁醇:三氯甲烷(1:1,V:V)萃取净化,经丹磺酰氯衍生,乙醚萃取后氮气吹干,用乙腈定容,高效液相色谱仪测定,内标法定量.结果 组胺含量在1～100 mg/L线性关系良好,线性相关系数r=0.9999,检...     

Determination of mycotoxins in cereals by liquid chromatography tandem mass spectrometry

A liquid chromatography tandem mass spectrometry (LC–MS/MS) method is described for simultaneous determination of aflatoxins (AFB₁, AFB₂, AFG₁ and AFG₂), ochratoxin A (OTA), zearalenone (ZEA), deoxynivalenol (DON), fumonisins (FB₁ and FB₂), T2 and HT2-toxin in cereals. One-step extraction using solvent mixtures of acetonitrile:water:acetic acid (79:20:1) without any clean-up was employed for extraction of these mycotoxins from cereals. The mean recoveries of mycotoxins in spiked cereals ranged from 76.8% to 108.4%. Limits of detection (LOD) and quantification (LOQ) ranged 0.01–20 and 0.02–40 ng/g, respectively. The developed method has been applied for the determination of mycotoxins in 100 cereal samples collected from Malaysian markets. A total of 77 cereal samples (77%) contaminated with at least one of these mycotoxins. Occurrence of mycotoxins in commercial cereal samples were 70%, 40%, 25%, 36%, 19%, 13%, 16, and 16% for aflatoxins, OTA, ZEA, DON, FB₁, FB₂, T2 and HT2-toxin, respectively. The results demonstrated that the procedure was suitable for the determination of mycotoxins in cereals and could be implemented for the routine analysis.     

毛细管气相色谱内标法测定酱油中的乙酰丙酸

选用正十一烷酸为内标,采用毛细管气相色谱法测定酱 油中的乙酰丙酸,样品回收率在83.4%～91.2％之间,标准 线性关系良好,样品测定的变异系数小。结果表明,采用 该方法具有操作简便、快速、准确等优点。      

Determination of tetracyclines in pig and other meat samples using liquid chromatography coupled with diode array and tandem mass spectrometric detectors

Two high performance liquid chromatographic methods (HPLC–DAD and LC–MS/MS) were developed to analyze tetracycline (TC) residues in pig meat (pork) samples. The method involved a sample preparation using a solid–liquid extraction (SLE) by McIlvaine buffer, followed by a solid-phase extraction (SPE) clean-up using Strata-XL cartridges. The developed sample clean-up resulted in a selective chromatogram in the HPLC–DAD separation and a reduced matrix effect (ME) in LC–MS/MS analysis. Moreover, HPLC columns packed with core–shell particles were tested for separation, which further enhanced the sensitivity and the selectivity of determinations. The validation of the methods for pig samples was carried out according to European Union 2002/657/EC decision. In addition, validation was also performed for bovine, chicken, and turkey meat samples using HPLC–DAD method. The performance characteristics of determinations were evaluated with both spiked and incurred samples, and were systematically compared. LC–MS/MS technique was found to be more accurate for spiked samples; however, HPLC–DAD method resulted in more reliable concentrations for incurred samples.     

顶空进样气相色谱法测定酱油中乙酰丙酸

研究了采用顶空进样气相色谱分析测定酱油中乙酰丙酸的方法。试验结果的变异系数CV＜9％，在0．01％－0．4％范围内，线性良好，回收率为85％以上。     

同位素稀释超高效液相色谱-串联质谱法测定 酱油、醋和饮料中的4-甲基咪唑

目的建立酱油、醋和饮料中4-甲基咪唑(4-methylimidazole,4-Me I)的超高效液相色谱-串联质谱检测方法。方法酱油、醋和饮料样品通过MCX固相萃取柱进行净化处理,采用乙腈-水(含0.05%氨水)作为色谱分离条件,在MRM模式下采集4-Me I的信号,同位素内标法定量。结果目标化合物的线性范围为10~1000μg/L,相关系数R为0.9995,三个添加水平的平均回收率为90.5%~101.6%,相对标准偏差(RSD)6.6%。所有被检测的样品中均含有4-Me I,酱油样品中含有的4-Me I的浓度范围为23.3~4310.8μg/L,平均值为823.3μg/L;醋样品中含有的4-Me I的浓度范围为111.2~2077.8μg/L,平均值为622.5μg/L;饮料样品中含有的4-Me I的浓度范围为10.8~307.1μg/L,平均值为94.8μg/L。结论本方法简单、快速、灵敏度高,适用于检测酱油、醋和饮料中4-Me I。     

酱油中苯甲酸含量的快速测定

采用面积归一化和标准曲线综合定量分析的方法，建立毛细管柱气相色谱测定食品调味料酱油中防腐剂——苯甲酸含量的方法。实验结果表明：样品回收率高，均在98．6%-102．8％之间；工作曲线线性关系较好，线性范围在0．1mg/mL-1．0mg/mL，相关系数为0．9994；样品测定的变异系数小，变异系数为1．54％。本法具有简便、快速、准确度高和重现性好的特点，可以推广到其它液态调味品苯甲酸含量的测定。     

Analysis of coumarin in various foods using liquid chromatography with tandem mass spectrometric detection

Recently authorities and the media have published reports of increased coumarin levels in Christmas biscuits, gingerbread, cinnamon cookies and other foods. The maximum tolerance limits for coumarin in food are set out in EC Directive 88/388/ECC. Since the standard use of analytical techniques, such as HPLC–UV, are only limitedly suitable for verifying compliance with the regulatory limit of 2 mg/kg for coumarin in food, a selective, sensitive isotope dilution LC–MS/MS method for determining coumarin content in foods was developed, tested and validated, and the results then compared to the HPLC–UV method. This LC–MS/MS method increased selectivity and raised sensitivity by a factor of 100 compared to the HPLC–UV technique. The respective limits of determination and quantification for the method were 0.03 and 0.05 mg/kg, respectively, with an RSD of 1–8% and a linearity range of 0.1–500 ng/mL (corresponding to 0.05–250 mg/kg in food). In addition, a selection of around 500 food samples was also tested for coumarin content using the LC−MS/MS technique.     

固相萃取--高效液相色谱法测定酱油中的防腐剂苯甲酸

提出了用固相萃取--高效液相色谱分离和测定酱油中的防腐剂苯甲酸的新方法。酱油中的苯甲酸用ENVl-18固相萃取小柱预分离,以IrregularC18(4.6mm20cm,10m)为分离柱,以methanol/ ammonium acetate(0.02mol/L)缓冲溶液按5∶95作为流动相,流速为1.00mL/min的线性等度洗脱,组分在其最大吸收波长230nm下检测,整个分离过程需6min内完成,其回收率在95.8%~106.2%之间,标准偏差为0.00104,RSD为0.31%,最低检测浓度可达到礸/L,具有良好的准确度和再现性。此法可以在未来的监测工作中大力推广使用。     

固相萃取技术在酱油有机物分析中的应用进展

酱油是日常生活中较为常用的调味品。随着社会对食品安全的重视,酱油中的有机物分析也日益受到关注。本文对近10年来国内外在酱油有机物分析中固相萃取(solid phase extraction,SPE)法的应用进行概述,归纳总结了主要用于酱油有机物分析的SPE法,可使用SPE法分析的酱油中的有机物种类,并对应用到酱油分析中的SPE方法使用的吸附剂进行总结和分类。     

毛细管柱气相色谱法测定蚝油中的山梨酸

采用毛细管柱气相色谱法测定蚝油中的山梨酸，此方法可使各组分得到良好分离，分析时间短，准确度高，相对标准偏差为1．35％～1.89％，样品加标回收率为90．4％～96．5％。     

Degradation study of enniatins by liquid chromatography–triple quadrupole linear ion trap mass spectrometry

Enniatins A, A₁, B and B₁ (ENs) are mycotoxins produced by Fusarium spp. and are normal contaminants of cereals and derivate products. In this study, the stability of ENs was evaluated during food processing by simulation of pasta cooking. Thermal treatments at different incubation times (5, 10 and 15 min) and different pH (4, 7 and 10) were applied in an aqueous system and pasta resembling system (PRS). The concentrations of the targeted mycotoxins were determined using liquid chromatography coupled to tandem mass spectrometry. High percentages of ENs reduction (81–100%) were evidenced in the PRS after the treatments at 5, 10 and 15 min of incubation. In contrast to the PRS, an important reduction of the ENs was obtained in the aqueous system after 15 min of incubation (82–100%). In general, no significant differences were observed between acid, neutral and basic solutions. Finally, several ENs degradation products were identified using the technique of liquid chromatography–triple quadrupole linear ion trap mass spectrometry.     

Simultaneous detection of flavonoids and phenolic acids in Herba Lysimachiae and Herba Desmodii Styracifolii using liquid chromatography tandem mass spectrometry

A sensitive liquid chromatography and tandem mass spectrometry (LC–MS/MS) method was developed and validated for the simultaneous analysis of 15 flavonoids and 3 phenolic acids in Herba Lysimachiae and Herba Desmodii Styracifolii. Separation was performed using a Diamonsil C₁₈ column, which was eluted with methanol (A) and 0.1‰ acetic acid (B). The gradient condition was as follows: 0–34 min, 20–34% A; 34–38 min, 34–95% A; maintained 95% A for the next 4 min. Analytes were detected using a hybrid quadrupole linear ion trap mass spectrometer that was equipped with an electrospray ionisation source in the negative ion and multiple-reaction monitoring modes. A full validation of the method was performed, including the linearity, precision, and accuracy, as well as limits of detection and quantification. The results indicated that the developed method was simple, sensitive and reliable. Furthermore, the method was successfully applied to differentiate 16 batches of Herba Lysimachiae and 21 batches of Herba Desmodii Styracifolii.     

耐盐乳酸菌在高盐稀态酱油中的应用

该文研究耐盐乳酸菌的分离、培养、保藏及其在高盐稀态酱油中与酵母菌的协同发酵作用，确定了可应用于高盐稀态酱油中的乳酸菌种类及添加时间和添加量。通过乳酸菌的作用使酱油颜色更加鲜亮、有光泽，并增加了酱油的香气。     

Amino acid composition,molecular weight distribution and antioxidant activity of protein hydrolysates of soy sauce lees

The proteins of soy sauce lees (SSLP) were hydrolysed by Alcalase in the presence of ultrasound or traditional water bath to obtain hydrolysates S2–S6. The analysis of protein content indicated that enzymatic hydrolysis could significantly improve the extraction efficiency of proteins. By determination of molecular weight distribution, >10 and 5–10 KDa fractions of native SSLP (S1) decreased during hydrolysis, whilst 3–5 KDa fraction increased. Gradual increases of free, total and antioxidant amino acids were observed for S1–S4, and the differences between S4 and S6 were slight. Tyrosine was the major free amino acid of S1–S6, whilst glutamic acid had the highest amount in total amino acid composition. S2–S6 showed stronger DPPH radical scavenging activities in a dose-dependent manner than S1. All the results suggested that ultrasound treatment showed an inhibition behaviour on the enzymatic hydrolysis of SSLP.     

气相色谱-质谱法测定酱油中氯丙醇类化合物

建立了酱油中两种氯丙醇类化合物检测的气相色谱-质谱分析方法.样品中加入两种稳定性氘代同位素内标,经基质固相分散萃取(MSPD)分步提取、净化,七氟丁酰基咪唑衍生化后进行GC/MS测定.两种氯丙醇化合物的线性范围均为10～1600 ng,检出限为5μg/kg;回收率为99.5%～110%,RSD%为3.8%～6.6%.该方法测定灵敏度高,定性准确,选择性好,稳定性高,适合于样品中多种痕量氯丙醇类化合物的同时测定.     

Quantitative analysis of acrylamide in tea by liquid chromatography coupled with electrospray ionization tandem mass spectrometry

An effective sample preparation procedure was optimized and a liquid chromatography–tandem mass spectrometry (LC–MS/MS) was developed for the quantitative analysis of acrylamide in tea. [¹³C₃]-acrylamide was used as internal standard. Acrylamide was extracted at 25 °C for 20 min by 10 ml water followed by 10 ml acetonitrile, and then 4 g of magnesium sulfate and 0.5 g of sodium chloride were added to the above mixture under stirring thoroughly. In order to increase the response of acrylamide, 9 ml acetonitrile layer was taken and concentrated to 0.5 ml. Solid-phase extraction with an Oasis MCX cartridge was carried out for clean-up. The limit of detection (LOD) and limit of quantification (LOQ) were 1 and 5 ng/ml, respectively. The recovery efficiency of the extraction procedure ranged between 74% and 79%. The levels of acrylamide in 30 tea samples were less than 100 ng/g. Black, oolong, white and yellow tea samples had quite low acrylamide contents (<20 ng/g). Higher acrylamide levels occurred in baked, roasted, and one sun-dried green tea samples (46–94 ng/g).     

高效液相色谱法测定酱油中苯甲酸含量

为了准确地测定酱油中苯甲酸含量,采用高效液相色谱法,以甲醇:乙酸铵溶液(0.02 mol/L)=5:95为流动相,总流速1.0 mL/min测定酱油中苯甲酸含量,此方法具有定量准确、精密度高和操作方便等特点.