Retrospective analysis for the identification of 4-aminocarminic acid photo-degradation products in beverages

This article deals with the identification of the photo-degradation products of 4-aminocarminic acid potentially present in commercial beverages. Sixteen beverages of different composition but all containing the E120 dye were previously analysed by ultra-high-performance liquid chromatography (UHPLC) coupled with quadrupole-time of flight mass spectrometry to identify the common degradation products of the E120 dye. Since it is plausible to find unauthorised 4-aminocarminic acid in beverages which report generic E120 dye on the label, retrospective analysis was employed here not only to search for the possible presence of 4-aminocarminic acid but also to investigate the potential formation of photo-degradation products derived from this compound. For this purpose, a statistical approach based on Student’s t-test was used to compare the degraded beverages containing 4-aminocarminic acid with all the others. Five degradation products were identified and their structures were elucidated on the basis of the high-accuracy and high-resolution of mass and mass/mass spectra. The toxicity of the degradation products was evaluated through the Ames Salmonella/microsome mutagenicity assay. No evidence of mutagenicity was obtained for the beverages subjected or not to irradiation, whereas a toxic effect of the 4-aminocarminic acid standard solution already at 100.0 µg l^?1 was found. This leads, once again, to the conclusion that the toxicity study must be carried out on the beverages in order to take into account of all the possible masking/protection interactions among the ingredients.     

Relative molar sensitivities of carnosol and carnosic acid with respect to diphenylamine allow accurate quantification of antioxidants in rosemary extract

We have been developing a high-performance liquid chromatography/photodiode array (HPLC/PDA) employing relative molar sensitivities (RMSs) and adopted it to the accurate quantification of carnosol (CL) and carnosic acid (CA) which are the antioxidants in rosemary extract. The method requires no references of CL or CA and instead uses RMSs with respect to diphenylamine (DPA) whose certified reference material is available from a reagent manufacturer. The molar and response ratios of the analytes to the reference in an artificial mixture of them were determined using ¹H-quantitative nuclear magnetic resonance spectroscopy (¹H-qNMR) and HPLC/PDA at a wavelength of 284 nm under isocratic condition, respectively, and then RMSs were calculated to be 0.111 for CL/DPA and 0.0809 for CA/DPA as averaged values in three HPLC–PDA instruments. The RMS values varied by up to 1.1% as relative standard deviation. To evaluate the performance of HPLC/PDA with the RMSs, the CL and CA contents in rosemary extracts were determined using DPA as a reference. The CL and CA contents were compared with those determined using calibration curves of CL and CA obtained by HPLC measurement of standard solutions prepared from their reagents whose absolute purities were determined using ¹H-qNMR. The differences between the two methods for CL and CA were ≤3% as relative error. This chromatographic method with RMSs allows a simple and reliable quantification when reference of the analyte is unavailable.     

高效液相色谱法快速测定食品中胭脂红酸(胭脂虫红)

目的 建立高效液相色谱法快速测定含蛋白和脂肪的食品中胭脂红酸（胭脂虫红）的分析方法。方法 采用2.0 mol/L HCl溶液，90 ℃水浴下酸解30 min，利用混合型强阴离子固相萃取小柱净化, 2%磷酸甲醇洗脱液注入高效液相色谱仪，由ZORBAX SB-C18 (150 mm×4.6 mm, 5 μm)快速分离后进入紫外检测器（494 nm和276 nm）进行测定。结果 含乳饮料、酸奶、调制乳粉、调制炼乳、熟肉制品、火锅底料食品中胭脂红酸（胭脂虫红）在0.1~5.0 μg/mL的范围内, 线性关系良好(r2≥0.999), 平均回收率在87.4%~95.1%之间, 相对标准偏差(relative standard deviations, RSDs)低于10%, 检出限(limits of detection, LODs)为0.3 mg/kg, 定量限(limits of quantitative, LOQs)为1.0 mg/kg。结论 此方法前处理准确性好、灵敏度高, 可实现含蛋白和脂肪食品基质中胭脂红酸（胭脂虫红）的快速测定。     

HPLC determination of thioglycolic acid and other aliphatic thiols in cosmetic formulations using ethacrynic acid as precolumn derivatization reagent

Limits imposed on the usage of thioglycolic acid, its salts and esters in cosmetic formulations require selective and sensitive analytical methods for their determination. In this study a convenient and reliable method based on high-performance liquid chromatography (HPLC) has been developed. The method involves a precolumn reaction of the thiol compounds with ethacrynic acid to give thiol adducts which can be separated by reversed-phase liquid chromatography and detected at λ= 273 nm.
The derivatization reaction proved to be quantitative under mild conditions (20 min at pH 7.4 and room temperature) and the chromatographic conditions allowed thioglycolic acid, glyceryl monothioglycolate, thiolactic acid, and thioglycolic acid ethyl ester to be discriminated.
The proposed method was successfully applied to the analysis of commercial cosmetic formulations containing thioglycolic acid and glyceryl monothioglycolate, fulfilling the requirements of a general and selective method for the analysis of aliphatic thiols in cosmetics.     

高效液相色谱法同时测定保健食品中的安石榴甙和鞣花酸

目的建立同时测定保健食品中安石榴甙、鞣花酸的高效液相色谱法(HPLC)方法。方法采用迪马钻石Ⅱ(4.6 mm×250 mm,5μm)色谱柱,乙腈+0.2%磷酸水溶液为流动相梯度洗脱,在波长256 nm下进行检测。结果方法的线性范围:α安石榴甙24～240μg/ml;β安石榴甙56.0～560μg/ml;鞣花酸60.0～600μg/ml。相关系数r为0.999 7～0.999 9;检出限:α安石榴甙、β安石榴甙、鞣花酸分别为2.36、2.78、2.67μg/g;定量限:7.08、8.34、8.01μg/g。高低两个浓度水平加标回收率97.5%～104%;相对标准偏差(RSD)均<2.5%。结论本方法简便、快速、准确、重现性好,适用于保健食品中安石榴甙和鞣花酸的测定。     

Classification of Turkish olive oils with respect to cultivar,geographic origin and harvest year,using fatty acid profile and mid-IR spectroscopy

Fatty acid composition and mid-infrared spectra of olive oils in combination with chemometric techniques were used in the classification of Turkish olive oils with respect to their varieties, growing location and harvest year. In particular, olive oil samples belonging to five different cultivars were obtained from the same orchard in the middle part of Aegean region and two of these varieties were also received from another orchard in northern part of the same region of Turkey in two consecutive harvest years. Evaluation of nine different fatty acid compositions with principal component analysis revealed clear differentiation with respect to variety, geographical origin and harvest year. On the other hand, mid-infrared spectra also achieved varietal and seasonal discrimination to some extent, but differentiation is not as clear as that obtained using fatty acid compositions.     

Simultaneous determination of theanine,gallic acid,purine alkaloids,catechins, and theaflavins in black tea using HPLC

In the present study, we employed high performance liquid chromatography with an amide‐C₁₆ column to determine the eighteen major active ingredients in black tea, including theanine, gallic acid, four purine alkaloids, eight catechins and four theaflavins. The method was successfully used to analyse two new kinds of black teas from the leaves of Camellia ptilophylla and Camellia kucha in China and several other world‐ famous black teas. Forty percentage ethanol was chosen as the extraction solvent for preparing tea extracts. All of the eighteen compounds could be separated within 86 min with a gradient elution system. Excellent linearity was observed for all the standard calibration curves, and correlation coefficients were above 0.9991. The developed method is accurate and sensitive enough for the determination of active components in black tea.     

毛细管气相色谱法测定果汁饮料中对羟基苯甲酸乙酯、对羟基苯甲酸丙酯的含量

建立了果汁饮料中对羟基苯甲酸乙酯、对羟基苯甲酸丙酯含量的毛细管气相色谱测定方法。该法采用WBI进样口、毛细管色谱柱J＆WDBl701（中等极性30mxO．53minx1μm、FID检测器进行检测。进样口温度230℃,载气流速10ml／mim．柱室温度1800℃恒温。检测器温度250℃,样品用盐酸溶液酸化,乙酸乙酯提取后直接进样测定。方法简单、快速、重现性好,平均回收率大于90％,RSD小于3．0％,线性范围为10-200μg／ml。     

Isolation of three curcuminoids for stability and simultaneous determination of only using one single standard substance in turmeric colour principles by HPLC with ternary gradient system

Based on high purities of curcumin, demethoxycurcumin and bisdemethoxycurcumin obtained by isolation and identified by NMR, MS and HPLC, this paper firstly studied feasibility of the method by HPLC, which used curcumin, the easily available constituent, as the external standard to directly determine the content of itself, and the same component in the analyte rather than the external component, as the internal standard to simultaneously determine the other two curcuminoids in turmeric source materials. Further, the stabilities of them alone or coexistence in turmeric colour principles were explored. The result showed that there were no significant differences between the present method and the external standard method conventionally used. And we found that demethoxycurcumin rather than curcumin and bisdemethoxycurcumin was quite instable. Thus, the study provided an alternative method to simultaneously determine three curcuminoids without multiple chemical standard substances and some valuable insight for the use of retaining demethoxycurcumin efficacy.     

Treatment of enzymatic wool with Fe3O4 nanoparticles and citric acid to enhance mechanical properties using RSM

In this work, protease enzymatic wool was treated with citric acid and Fe₃O₄ nanoparticles to produce fabric with enhanced tensile strength, elongation, alkali resistance with controllable hydrophilicity/hydrophobicity through a simple ‘impregnating’ method. Protease enzymatic is also one of the most important processes usually carried out in alkali condition to obtain the desirable characteristics, which enhanced the surface activity and nanoparticles adsorption. Mechanical properties such as tensile strength and elongation were reduced as a consequence of alkali enzymatic pretreatment. Here, with the help of citric acid cross-linking agent, Fe₃O₄ nanoparticles were stabilized on the enzymatic wool surface in a way to revenge reduction in the tensile strength, elongation, alkali resistance. In order to create optimum tensile strength, elongation, alkali resistance, lightness and hydrophilicity/hydrophobicity, the appropriate models were obtained based on Design-Expert software. Overall, the results confirmed that the enzymatic wool fabrics could be modified by citric acid and Fe₃O₄ nanoparticles post-treatment. The Fe₃O₄ nanoparticle/citric acid treatment on the protease enzymatic wool improved tensile strength and elongation along with the higher alkali resistance and controllable hydrophilicity/hydrophobicity.     

紫外双波长-pH转换法同时测定混合物中的丙酮酸和乳酸

建立了一种同时测试混合物中乳酸与丙酮酸含量的紫外分光光度方法。在碱性环境下,利用双波长法,测定混合物中的丙酮酸,线性回归方程C=6.75×10-3+0.626A,线性范围为0.0505⁰.505μg/mL;在酸性条件下,利用直接分光光度法,测定混合物中的乳酸,线性回归方程C=1.547+51.76A,线性范围为1.22²44μg/mL。采用本法测量工业样品,其结果与液相色谱法得到的数据基本吻合,但本法实验步骤更加简单、操作更加方便,且容易实现工艺过程的在线检测。      

QuEChERS-超高效液相色谱-串联质谱法同时测定豆芽中6-苄基腺嘌呤和4-氯苯氧乙酸的含量

目的建立QuEChERS-超高效液相色谱-串联质谱法同时测定豆芽中6-苄基腺嘌呤和4-氯苯氧乙酸含量的分析方法。方法样品以乙腈为提取溶剂,加入氯化钠盐析分层,经C_(18)填料萃取净化,采用电喷雾负离子扫描模式,多反应监测,外标法定量。结果 6-苄基腺嘌呤和4-氯苯氧乙酸在1～150μg/L范围内有良好的线性关系,相关系数均大于0.999, 6-苄基腺嘌呤方法检出限为1μg/kg, 4-氯苯氧乙酸方法检出限为0.5μg/kg。平均回收率为95.4%～104.1%,相对标准偏差为1.7%～8.2%。结论本方法灵敏度高,准确度和重复性好,适用于豆芽中违法添加6-苄基腺嘌呤和4-氯苯氧乙酸的检测。     

Short communication: Assessment of the potential of cinnamaldehyde, condensed tannins, and saponins to modify milk fatty acid composition of dairy cows

This study was conducted to determine whether feeding cinnamaldehyde (main component of cinnamon bark essential oil; Cinnamon cassia), condensed tannins from quebracho trees (Schinopsis balansae), or saponins from Yucca schidigera altered the milk fatty acid profile of dairy cows. For this purpose, 4 lactating cows were used in 4 × 4 Latin square design (28-d period) and fed a total mixed ration containing no additive (control), or supplemented with cinnamaldehyde (1 g/d; CIN), quebracho condensed tannin extract (150 g/d; 70% of tannins; QCT), or Yucca schidigera saponin extract (60 g/d; 10% of saponins; YSE). Results revealed no effects of feeding CIN or QCT on milk fatty acid profile. Supplementation with YSE resulted in some modifications of milk fatty acid profile as suggested by the reduced proportions of C6:0 (2.71 vs. 2.95%), C8:0 (1.66 vs. 1.89%), and trans-11 C18:1 (0.92 vs. 1.01%). Results show low potential of cinnamaldehyde, condensed tannins, and saponins to alter ruminal biohydrogenation process and modify the fatty acid profile of milk fat at the feeding rates used in this study. Further investigations are needed to determine the factors that limit the effects of these secondary metabolites on ruminal microbial populations involved in the biohydrogenation processes of unsaturated fatty acids.     

高效液相色谱法测定丽石黄衣中松萝酸的含量及抑菌活性的研究

以丽石黄衣(Xan thoria elegans (Link)Th.Fr.)为材料,乙酸乙酯为溶剂回流提取松萝酸,采用高效液相色谱法测定松萝酸的含量并用滤纸片法对松萝酸的抑菌作用进行了测定。实验结果表明,丽石黄衣中松萝酸的总含量为4.06%,松萝酸对酵母没有抑菌作用,可对其他受试细菌和真菌有抑菌作用。     

液相色谱-高分辨质谱法测定豆芽中4-氯苯氧乙酸的不确定度评估

目的评定液相色谱串联高分辨质谱法测定豆芽中4-氯苯氧乙酸含量的不确定度。方法按照SN/T3725-2013《出口食品中4-氯苯氧乙酸残留量的测定》测定豆芽中4-氯苯氧乙酸,根据JJF 1059.1-2012《测定不确定度评定与表示》的方法,建立高分辨液质联用法测定豆芽中4-氯苯氧乙酸不确定度评定的数学模型,分析其中各不确定度分量的来源,并对其分别进行量化,最终合成豆芽中4-氯苯氧乙酸含量测定结果的不确定度。结果豆芽中4-氯苯氧乙酸含量测定结果为35.11μg/kg时,在95%的置信区间下,扩展不确定度为4.28μg/kg(k=2)。结论标准溶液的配制是实验过程不确定度主要来源。     

对氯甲基苯甲酸链接的莱克多巴胺人工抗原的合成与鉴定

采用对氯甲基苯甲酸(CBA)为链接臂,用混合酸酐法将莱克多巴胺(RAC)与牛血清白蛋白(BSA)偶联制备人工抗原(RAC-CBA-BSA),通过紫外、红外、电泳鉴定抗原合成成功;再以卵清蛋白(OVA)为载体蛋白合成包被抗原(RAC-CBA-OVA),测定其与抗体的亲和力和抑制率。间接竞争ELISA结果以对CBA为链接臂合成的包被抗原对应的抗体滴度为7047.3、IC50为17.05ng/mL,结果表明,CBA可以用于RAC人工抗原的合成,使用RAC-CBA-OVA作为包被抗原可以提高ELISA检测灵敏度。     

多元载体固载磷钨酸催化剂的研制及绿色合成己二酸

以质量比1∶9∶20的氯化镧、高岭土和SnCl4.5H2O制备了多元载体SnO2-La2O3-高岭土,将其于磷钨酸的乙醇溶液中浸渍12h,300℃焙烧3h,得多元载体固载磷钨酸催化剂PW12/SnO2-La2O3-高岭土,并采用IR和XRD测试技术表征了催化剂的物化性质。以30%H2O2为氧源,无需在反应体系中使用有机溶剂和相转移剂,用于催化氧化环己酮绿色合成了己二酸。结果表明,该方法有益于降低成本、简化分离工艺、减少污染和提高产品质量,催化剂还有一定的重复使用性。适宜反应条件为环己酮100mmol,催化剂1.5g,30%H2O245mL,回流反应6h,己二酸收率63.90%。     

Production of lipase-catalyzed structured lipids from safflower oil with conjugated linoleic acid and oxidation studies with rosemary extracts

Structured lipid (SL-safflower) was produced by lipase-catalyzed esterification (acidolysis) from safflower oil and conjugated linoleic acid (CLA). SL-safflower was then isolated by alkaline de-acidification, and its chemical characteristics were studied. Also, the change of fatty acid composition and tocopherol content was monitored during the reaction. After 2 h reaction, 18.5 mol% CLA was incorporated into SL-safflower, which further increased to 22.5 mol% after 24 h reaction. The content of -tocopherol was gradually reduced to more than 85% after 24 h. Besides, the oxidative stabilities of SL-safflower and safflower oil were studied. SL-safflower showed higher peroxide value (POV), ρ-anisidine value (AV), and 2-thiobarbituric acid reactive substances (TBARS) value than safflower oil, indicating that SL-safflower containing CLA is more susceptible to oxidation than safflower oil. Rosemary extracts with different amount (100, 200 or 300 ppm) could effectively reduce the oxidation, showing the most effective at 300 ppm.