First approach based on direct ultrasonic assisted enzymatic digestion and capillary-high performance liquid chromatography for the peptide mapping of soybean proteins

This work proposes, for the first time, the use of a high intensity ultrasonic probe to accelerate the tryptic digestion of soybean proteins. Different digestion parameters were optimized: protein extracting solution, reduction, and alkylation conditions (time, concentration, and temperature), trypsin:protein ratio, and ultrasonic conditions (sonication amplitude and time). Separation of peptide profiles was carried out by capillary-HPLC. The effect of the variation of chromatographic conditions (elution gradient, column temperature, and injection volume) on peptide separation was also studied using two capillary-HPLC columns with different column diameters and particle sizes. Moreover, samples were focused at the top of the column in order to obtain an increasing sensitivity without loss of efficiency. This method was successfully applied to the profiling of soybean peptides from transgenic and non-transgenic soybeans and from different pigmented beans commercialized as soybeans.     

多维液相色谱-质谱用于酶解猪血蛋白中活性肽的研究

以强阳离子交换柱（SCX）为一维色谱柱,反相柱（RP）为二维色谱柱,采用在线捕集接口形式,通过10通阀连接一、二维色谱柱,构建了二维液相色谱分离系统。将该系统用于酶解猪血蛋白中对血管紧缩素Ⅰ转移酶（ACE）具有活性抑制作用的肽进行分离、鉴定,共检测出104个组分。收集一维馏分,离线注入LC—MS,鉴定出其中含有SAL、DKF、ESF、STVL及FESF5个小肽。     

高效液相色谱法测定保健食品中的大豆异黄酮

建立了一种测定保健食品中大豆异黄酮的高效液相色谱分析方法,该方法可以使常见的大豆异黄酮6种主要成分大豆甙、黄豆甙、染料木甙、大豆甙元、黄豆黄素、染料木素得以分离和检测。采用乙腈-磷酸水溶液(pH2.8)作流动相,梯度洗脱,Venusil MP-C18色谱柱(150 mm×4.6 mmi.d.,5μm),流速为1.0 mL/min,紫外检测器,检测波长254 nm。结果表明各组分线性关系良好,相关系数R2为0.9991~0.9998,加标回收率在87%~106.9%,相对标准偏差均小于2%。检出限0.25~0.48μg/mL,该方法可同时测定大豆异黄酮的6种成分。     

Simultaneous and rapid determination of the anticarcinogenic proteins Bowman-Birk inhibitor and lectin in soybean crops by perfusion RP-HPLC

There are numerous studies demonstrating a direct association between the ingestion of soybean and low cancer incidence. This fact has been related to the presence of Bowman-Birk inhibitor (BBI) and lectin in soybean. The simultaneous and fast determination of BBI and lectin in soybean is proposed, for the first time, in this work. Two different strategies were designed for the extraction of BBI and lectin: extraction of soybean proteins using a Tris-HCl buffer followed by isolation of BBI and lectin by the isoelectric precipitation of other soybean proteins (method I) or by the direct extraction of BBI and lectin using an acetate buffer (method II). The effect of the previous soybean defating on the extraction of BBI and lectin was also studied. Moreover, the possibility of using a high-intensity focalized ultrasonic probe for accelerating the extraction was explored and an optimization of the extraction time and ultrasound amplitude was performed. The extracts obtained were analysed by RP-HPLC-ESI-MS for the correct identification of BBI and lectin in soybean. Moreover, a fast chromatographic methodology using a perfusion column and UV detection was optimized for the rapid determination of BBI and lectin in soybean. After evaluating its analytical characteristics (linearity, precision, and recovery), the method was applied to the quantitation of BBI and lectin in different soybean varieties.     

Fast analysis of isoflavones by high-performance liquid chromatography using a column packed with fused-core particles

The recent development of fused-core technology in HPLC columns is enabling faster and highly efficient separations. This technology was evaluated for the development of an fast analysis method for the most relevant soy isoflavones. A step-by-step strategy was used to optimize temperature (25-50 °C), flow rate (1.2-2.7 mL/min), mobile phase composition and equilibration time (1-5 min). Optimized conditions provided a method for the separation of all isoflavones in less than 5.8 min and total analysis time (sample-to-sample) of 11.5 min. Evaluation of chromatographic performance revealed excellent reproducibility, resolution, selectivity, peak symmetry and low limits of detection and quantification levels. The use of a fused-core column allows highly efficient, sensitive, accurate and reproducible determination of isoflavones with an outstanding sample throughout and resolution. The developed method was validated with different soy samples with a total isoflavone concentration ranging from 1941.53 to 2460.84 μg g⁻¹ with the predominant isoflavones being isoflavone glucosides and malonyl derivatives.     

高效液相色谱法分析大豆中磷脂酰胆碱的分子种

用高效液相色谱法（HPLC）在正相半制备硅胶柱上将大豆磷脂酰胆碱与其它组分分离，从柱后收集磷脂酰胆碱（PC），然后在反相C18柱上分析其分子种组成，蒸发光散射检测器检测。在25min内将大豆磷脂酰胆碱分离成11个分子种组分，使用易挥发溶剂，可获得各种分子种的纯物质，供进一步分析。分子种根据HPLC峰的脂肪酸组成分析而确定。     

Fast determination of tetracycline antibiotics in different media by high-performance liquid chromatography

Summary The use of high-performance liquid chromatography (HPLC) for the identification and determination of tetracycline antibiotics is reviewed. HPLC chromatograms provide fast identification by retention time, t_R, and precise quantitation by measurement of peak height or peak area. For separation of tetracycline compounds, most HPLC methods use reversed-phase C₁₈ or C₈ columns and UV detection. The HPLC solvent system should have a pH of about 6 to prevent steric changes in the tetracycline molecule. For accurate quantitation it is necessary to avoid tailing and this is accomplished by adding a zwitter ion to the solvent system. Methanol and acetonitrile are frequently used as organic modifiers in these solvent systems. In a single analysis, HPLC methods can be used to separate as many as nine or ten commercially used tetracycline compounds and to determine four to five tetracyclines in commercial tetracycline preparations or in biological fluids.     

超高效液相色谱法同时测定减肥类保健食品中非法添加的25种药物

建立了采用超高效液相色谱同时测定减肥类保健食品中25种非法添加化学药物含量的方法。保健食品样品以甲醇为提取溶剂进行超声提取,离心后取上清液以Waters HSS T3色谱柱(100 mm×2.1 mm,1.8 μm)进行分离,乙腈和10 mmol/L乙酸铵水溶液(含0.1%甲酸)为流动相梯度洗脱,流速为0.3 mL/min,在200~400 nm波长范围内进行定性和定量分析。在相应的浓度范围内,25种化学药物的质量浓度与峰面积呈良好的线性关系,R²≥0.997;定量限在0.500~5.00 ng之间;在低、中、高3个添加水平范围内的平均回收率为70.7%~104%,相对标准偏差(RSD)在0.132%~5.03%之间。样品筛查结果发现,17种减肥保健食品中3种样品非法添加了酚酞,1种样品添加了大黄素。该方法选择性强、分析速度快、高通量,可用于该类保健食品中非法添加化学药品的定性筛查和定量检测。     

高效液相色谱法测定食品中氟啶脲的残留量

建立了高效液相色谱测定食品中氟啶脲残留量的方法.样品中的氟啶脲经正己烷或乙腈提取,弗罗里硅土净化后,以乙腈-水( 85:15,v/v)混合溶液为流动相,经C18色谱柱分离,紫外检测器(260 nm)测定.结果表明:氟啶脲在0 05 ～2.0 mg/L范围内线性良好(相关系数为0 999 8),定量限(以信噪比为10计)...     

Fast determination of ginsenosides in ginseng by high‐performance liquid chromatography with chemometric resolution

Ginseng is a well‐known traditional Chinese medicinal herb, and ginsenosides are its major active components. A method for the fast determination of ginsenosides in ginseng samples by high‐performance liquid chromatography was developed and used for the quantitative analysis of four ginsenosides in three different ginseng samples. In this method, instead of time‐consuming gradient elution, isocratic elution was used to speed up the analysis. Under strong isocratic elution, all the ginsenosides are eluted in 2.3 min. Although the measured signal is composed of overlapped peaks with the interferences and background, the signal of ginsenosides can be extracted by chemometric resolution. A non‐negative immune algorithm was employed to obtain the chromatographic information of the target components from the data. Compared with conventional chemometric approaches, the method can perform the extraction for one‐dimensional overlapping signals. The method was validated by the determination of four ginsenosides in three different ginseng samples. The recoveries of the spiked samples were in the range of 94.08–107.3%.     

Fast and simultaneous determination of phenolic compounds and caffeine in teas, mate, instant coffee, soft drink and energetic drink by high-performance liquid chromatography using a fused-core column

A fast HPLC method with diode-array absorbance detector and fluorescence detector for the analysis of 19 phenolic acids, flavan-3-ols, flavones, flavonols and caffeine in different types of samples was developed. Using a C₁₈ reverse-phase fused-core column separation of all compounds was achieved in less than 5 min with an overall sample-to-sample time of 10 min. Evaluation of chromatographic performance revealed excellent reproducibility, resolution, selectivity and peak symmetry. Limits of detection for all analyzed compounds ranged from 0.5 to 211 μg L⁻¹, while limits of quantitation ranged between 1.5 and 704 μg L⁻¹. The developed method was used for the determination of analytes present in different samples, including teas (black, white, green), mate, coffee, cola soft drink and an energetic drink. Concentration of the analyzed compounds occurring in the samples ranged from 0.4 to 314 mg L⁻¹. Caffeine was the analyte found in higher concentrations in all samples. Phytochemical profiles of the samples were consistent with those reported in the literature.     

高效液相色谱-串联质谱法测定动物源食品中粘杆菌素、多粘菌素B的残留量

建立了动物源食品中粘杆菌素和多粘菌素B残留的高效液相色谱-串联质谱(HPLC-MS/MS)测定方法。样品用V(10%三氯乙酸水溶液):V(乙腈)=30:70提取,Oasis WCX SPE柱净化,LC-MS/MS电喷雾正离子多反应监测模式(ESI+-MRM)检测。分析物在0～250μg/kg的浓度范围内呈良好线性,线性相关系数>0.995。方法的定量限为10μg/kg。方法在三个添加水平的平均回收率在71.6%～78.9%之间,相对标准偏差在6.2%～12%之间。方法适用于动物源食品中粘杆菌素和多粘菌素B的定量及确证检测。     

正相高效液相色谱法测定食物中8种维生素E异构体及维生素A

建立了正相高效液相色谱测定食物中8种维生素E异构体及维生素A的方法。样品中的维生素E异构体和维生素A经皂化和液液萃取,Waters ACQUITY^TM UPLC BEH Amide色谱柱(150 mm×3.0 mm, 1.7 μm)分离,体积比为90 : 10的正己烷与叔丁基甲基醚-四氢呋喃-甲醇(20:10:1, v/v/v)为流动相,荧光检测器和紫外检测器串联检测。4种生育酚在5.0~60.0 mg/L(r²≥0.9999)、维生素A和4种三烯生育酚在0.5~6.0 mg/L(r²≥0.9996)范围内具有良好的线性,各基质中目标物的检出限在20~60 μg/kg之间;9个组分在各基质中的加标回收率为79.2%~114.2%,相对标准偏差(RSD)为1%~12%。该方法简便、灵敏、可靠、环保,可用于食物中8种维生素E异构体以及维生素A含量的同时测定。     

高效液相色谱-串联质谱法同时测定食品中五种黄色化工染料

采用高效液相色谱-串联质谱法(HPLC-MS/MS)建立了食品中非法添加的碱性橙、碱性嫩黄、酸性橙I、酸性橙II和酸性黄36这5种黄色工业染料的定量定性分析方法。使用Agilent ODS C18分离柱(50 mm×2.0 mm, 1.8 μm),以5 mmol/L乙酸铵水溶液(0.1%甲酸)-乙腈(3:2, v/v)为流动相,流速为0.3 mL/min。采用电喷雾离子化源,以多反应监测(MRM)方式分别在正、负离子模式下进行检测。在最佳检测条件下,得到了较宽的线性范围和较低的定量检出限。碱性橙和碱性嫩黄的线性范围均为5.0～80.0 mg/L;酸性橙I、酸性橙II及酸性黄36的线性范围均为10.0～160.0 μg/L。食品中碱性橙、碱性嫩黄、酸性橙I、酸性橙II及酸性黄36的定量限分别为20、20、40、40、40 ng/g。该方法重现性较好,保留时间和峰面积的相对标准偏差分别不大于0.50%和2.14%。本研究还测定了鸡肉、豆制品和黄鱼中添加的5种化工染料,回收率在79.8%~95.2%之间,结果令人满意。     

Quantitative determination of isoflavones and coumestrol in soybean by column liquid chromatography

Four different stationary phases and a variety of solvents in varying proportions were examined in this study. Daidzein, genistein, formononetin, biochanin A and coumestrol were separated within 24 min on a phenyl column with acetonitrile-water (33:67, v/v) as eluent. The proposed method showed an acceptable repeatability with a RSD of quantitation <6%. The mean recoveries of daidzein, genistein, formononetin, biochanin A and coumestrol from soybean ranged from 89 to 104%. The identity of the individual analytes was confirmed by LC-MS-MS. The four isoflavones and coumestrol were isolated from soybean by hydrolysis with acid and heat. Neutralization of the soybean samples prior to identification did not alter the concentration of daidzein and genistein in soybean.     

Fluorimetric determination of pantothenic acid in foods by liquid chromatography with post-column derivatization

A method to determine the content of free pantothenic acid in various foods by reverse phase liquid chromatography-fluorimetry is reported. It includes a purification of the samples by successive passages through anion and cation exchange cartridges and a post-column derivatization of pantothenic acid as the fluorescent 1-alkylthio-2-alkylisoindole (reaction of beta-alanin, formed by hot alkaline hydrolysis of pantothenic acid, with orthophthaldialdehyde in the presence of 3-mercaptopropionic acid). An enzymatic hydrolysis prior to the purification step (pepsin at 50 degrees C for 3 h, then pantetheinase and alkaline phosphatase at 20 degrees C for 18 h) made it possible to release the bound pantothenic acid and thus to obtain the total Vitamin B5 content of these foodstuffs. The method proposed for the determination of free and bound pantothenic acid gives a good recovery rate (96-101%) and a satisfactory repeatability (R.S.D.r less than 8%). Owing to its low detection limit (0.65 microg g(-1)) and the good resolution of the pantothenic acid peak, it could most probably be applied to the determination of this vitamin in any foodstuff.     

Rapid determination of nitrite in foods in acidic conditions by high‐performance liquid chromatography with fluorescence detection

In this study, a simple, rapid, and sensitive method for the determination of nitrite (NO₂^?) in food samples by high‐performance liquid chromatography with fluorescence detection in acidic conditions had been developed. The derivatization of the nitrite with 2,3‐diaminonaphthalene was performed in acidic conditions to yield the highly fluorescent 2,3‐naphthotriazole, which was directly analyzed by high‐performance liquid chromatography with fluorescence detection without adjusting the solution to alkaline. The analysis column was reversed‐phase C₈ column. A constant flow rate of 1.0 mL/min was employed using water/acetonitrile as the mobile phase in isocratic mode (70:30, v/v). Fluorescence was monitored with excitation at 375 nm and emission at 415 nm. The standard calibration curves were linear for nitrite in different matrixes in the concentration range of 0–100 μg/L, and the correlation coefficients ranged from 0.9978 to 0.9998. The limits of detection and quantification were in the ranges of 0.012–0.060 and 0.040–0.20 mg/kg, respectively. The recoveries of nitrite from samples spiked at three different concentrations were 74.0–113.2%, and the relative standard deviations of the recovery results (n = 6) were 1.67–10.8%. The proposed method has good repeatability and is very sensitive and simple. It has been successfully used to determine nitrite in foods.     

高效液相色谱法测定保健食品和饮料中的阿斯巴甜

建立了保健食品和饮料中的甜味剂阿斯巴甜的高效液相色谱快速测定方法.固体样品用纯水超声提取;饮料样品超声脱气.取适量提取液或饮料样品,经0.45 μm滤膜过滤后,取20 μL进样色谱柱分析.色谱条件:分离柱为C18柱(250mm×4.6 mm i.d.,10μm),柱温35℃,流动相为V(10 mmol/L KH2PO4,pH 3.50):V(乙腈)=80:20,流速1 mL/min,检测波长210 nm.本法线性范围为0～16 μg,最低检出量为0.0024 μg,回收率为92.3%～102%.相对标准差小于1.6%.本法准确度和精密度均能满足保健食品和饮料中阿斯巴甜测定的要求.     

高效液相色谱-串联质谱法同时测定减肥保健食品中非法添加的药物利莫那班和奥利司他

建立了一种专属、灵敏的同时测定减肥保健食品中非法添加的药物利莫那班和奥利司他的高效液相色谱-串联质谱分析方法。不同类型的减肥保健食品经加速溶剂萃取后,用甲醇和10 mmol/L乙酸铵水溶液作流动相,采用梯度洗脱方式以Waters Atlantis T3色谱柱(150 mm×2.1 mm, 3 μm)分离,以电喷雾离子源正离子检测方式进行质谱分析。实验结果表明,利莫那班和奥利司他的方法检出限为0.5 mg/kg;在0.5～100 μg/L范围内呈良好的线性关系,相关系数分别为0.9989和0.9994;在2, 5, 10 mg/kg 3个添加水平范围内的平均回收率为80.5%～102.1%;日内精密度均小于6%,日间精密度均小于8%。同时研究了这两种药物的质谱特征,推测了其质谱裂解途径。本方法灵敏度高,重现性好,可用于不同类型减肥保健食品中非法添加的奥利司他和利莫那班的检测。