反相液液微萃取/高效液相色谱测定变压器油中糠酸的含量

以水为萃取剂,建立了变压器油中糠酸含量的反相液液微萃取/高效液相色谱测定方法。通过研究萃取剂的p H值、萃取剂体积、稀释剂用量、萃取时间及离心转速的影响,确定了最优的萃取条件。结果表明:在以中性水为萃取剂,萃取剂体积为150μL,稀释剂比例V油∶V正己烷为3∶1,涡旋萃取时间为5 min,离心转速为5 500 r/min的条件下,水萃取相直接用于高效液相色谱测定,变压器油中糠酸的浓度在0.05~5.00 mg·L-1范围内呈良好线性,相关系数(r)为0.999 9,方法的检出限为9.6μg·L-1,相对标准偏差(RSD,n=6)为1.4%,糠酸的富集倍数为13.6倍。实际老化样品测定的加标回收率为99.7%~105.1%,并对样品中的糠酸进行了HPLC-MS定性分析。该方法简捷有效,为变压器油纸绝缘老化特征量的研究提供了数据支持。     

液液微萃取联合高效液相色谱法测定变压器绝缘油中腐蚀性硫化物二苄基二硫醚

建立了涡旋液液微萃取(VA-LLME)联合高效液相色谱(HPLC)测定变压器绝缘油中主要腐蚀性硫化物二苄基二硫醚(DBDS)含量的方法。以乙腈为萃取剂,在最佳条件下,同时采用外标法和内标法进行分析。实验结果表明,变压器油中DBDS含量在0.1～600.0 mg/kg范围内线性关系良好,相关系数(r)大于0.999,检出限为6.9～7.1μg/kg。将该方法用于商品变压器油及老化变压器油中目标分析物的测定,其加标回收率为95.0%～112%,RSD不大于2.3%。该方法具有高效、灵敏和环境友好的特点,与现行美国IEC 62697的GC-ECD方法和我国GB/T 32508的GC-MS方法无显著性差异。相关研究可为我国变压器油中腐蚀性硫化物DBDS定量检测方法的标准修订提供参考。     

蔬菜中苯甲酰脲类药物残留的测定方法研究

建立了一步有机溶剂提取、HPLC分离、紫外检测器检测7种苯甲酰脲类药物(除虫脲、灭幼脲、杀铃脲、氟铃脲、氟苯脲、氟虫脲和氟啶脲)在蔬菜中残留量的方法。考察了不同提取溶剂(乙酸乙酯和乙腈)的提取效率;研究了不同C18固相萃取小柱、活性碳、自制弗罗里硅土柱和GPC对蔬菜样品的净化效果;实验了不同的梯度淋洗程序分离7种药物。通过对黄瓜、大白菜、西红柿和包心菜4种蔬菜的4种添加水平和4次重复性实验,建立了一种以乙腈为提取溶剂和以弗罗里硅土柱为净化柱的高效液相色谱法测定7种苯甲酰脲类药物。该方法线性范围为:0.02~1.5mg/L,7种苯甲酰脲类药物的相关系数均大于0.999,其检出限为0.02~0.05mg/kg(S/N=10);在0.05~1.0mg/kg之间的添加回收率为80%~120%;相对标准偏差小于15%。方法完全符合残留分析的要求。     

Purity and Stability of Urea,Creatinine and Uric Acid Standards

Abstract

The significance to the routine laboratory of instability and inter-manufacturer variation of various standards previously demonstrated by HPLC analysis was investigated by chemical analysis. Urea, creatinine and uric acid standards from several manufacturers were studied. The causes and consequences of the demonstrated impurities, variations and instability of the standards are discussed.     

食用植物油中胆固醇含量的快速测定

将食用植物油直接用无水乙醇完全溶解,经滤膜过滤后,用高效液相色谱法测定其中的胆固醇含量。HPLC条件：Diamonsil C18色谱柱（250mm×4．6mm,5μm）,100％甲醇为流动相,流速1．0mL／min,柱温38℃,检测波长208nm。方法的检出限为50mg／L,加标回收率在91．5％-101．4％之间,测定结果的相对标准偏差为2．12％-4．15％。该法适用于食用植物油中胆固醇含量的快速测定。     

氯磺隆的高效液相色谱分析方法研究

本文研究了用高效液相色谱法测定新型除草剂氯磺隆含量的方法,在反相ODS柱上,用甲醇—水作流动相进行洗脱,紫外225nm检测,以萘作内标定量,方法快速、灵敏、准确,氯磺隆的最小检出量为0.8ng,变异系数为1.4%,回收率为100.7%,一次分析仅需3分钟。     

Quantification of Diaminomaleonitrile Using High Performance Liquid Chromatography with UV and Electrospray Ionization Mass Spectrometric Detection

Abstract

A method was developed to quantify diaminomaleonitrile (DAMN) in complex aqueous matrices using high performance liquid chromatography with UV and electrospray ionization mass spectrometric (ESI-MS) detection. The method is rapid (analytical times <10 min), able to quantify DAMN against complex backgrounds, and achieved with part per billion detection limits. Given the central role of DAMN in generating heterocycles of known biological significance, this study provides a rapid and sensitive method for quantifying DAMN in complex solutions.     

Determination of eight polyphenols and pantothenic acid in extra‐virgin olive oil samples by a simple,fast, high‐throughput and sensitive ultra high performance liquid chromatography with tandem mass spectrometry method

A new ultra high performance liquid chromatography coupled with tandem mass spectrometry method for a fast and sensitive determination of eight polyphenols (hydroxytyrosol, catechin, epicatechin, epigallocatechin gallate, oleuropein, quercetin, rutin, tyrosol) and panthotenic acid in extra‐virgin olive oil was developed. The method does not require long sample pre‐treatment and presents the lowest limit of detection and limit of quantitation values present in literature. Inter‐ and intra‐day variability, linear dynamic range of the calibration curve, recovery and matrix effect were also determined and investigated. The method was applied to several oil samples of different type and origin. Given its accuracy, precision and rapidity, the method is characterized by an interestingly high throughput, reliability, and sensitivity.     

复杂基体中痕量多环芳烃分析测定方法的研究进展

介绍了环境样品（水和土壤）以及植物油中痕量多环芳烃的分析检测方法。对样品的预处理过程和分析方法做了评价。采用一些新的预处理方法（包括液相色谱法、固相萃取法、超临界二氧化碳萃取法）,并结合色谱-质谱在线联用分析检测方法能够获得比较理想的分析结果。引用文献52篇。     

亚种间杂交稻内源激素的高效液相测定法

 建立了一种快速、提取率高的从植物中提取内源激素的样品处理方法 ,并研究了高效液相法测定亚种间杂交稻的 4种内源激素 :赤霉素 (GA3 )、3 吲哚乙酸 (IAA)、玉米素 (Z)和脱落酸 (ABA)的条件。采用WatersC18反相柱 (4 6mmi.d .× 2 5 0mm ,5 μm) ,SPD 6AV紫外检测器。以甲醇 水 乙酸 (体积比为 45∶5 4 2∶0 8)溶液为流动相 ,流速 1 0mL/min ;进样量 2 0 μL ;检测波长 2 5 4nm ;选用外标法进行定量测定。其回收率高 ,检出限分别为GA3 0 5mg/L ,IAA 0 1mg/L ,Z 0 3mg/L ,ABA 0 0 3mg/L。该法快速、灵敏、准确。     

高效液相色谱法分离测定牦牛乳中的8种蛋白质

建立了同时分离和测定牦牛乳中4种酪蛋白和4种乳清蛋白的反相高效液相色谱方法。脱脂牦牛乳经分散剂处理后,采用C4色谱柱(250 mm×4.6 mm,300,5μm i.d.)进行分离,以0.1%的三氟乙酸水溶液和0.1%的三氟乙酸乙腈溶液为流动相,流速为0.8 mL/min,梯度洗脱,二极管阵列检测器(DAD)在220nm波长下检测,外标法定量。结果表明,牦牛乳中8种主要蛋白质在40 min内完全分离,在各自的线性范围内呈良好线性,除α-乳白蛋白外,其余7种蛋白的相关系数均大于0.99。8种蛋白质的回收率为86%～103%,相对标准偏差(RSDs)为1.7%～8.7%;检出限(LODs)为10.7～39.2 mg/L,定量下限(LOQs)为35.7～130.7 mg/L。该方法的准确度和精密度均较高,能够满足实际检测的要求。     

Fast determination of virgin olive oil phenolic metabolites in human high‐density lipoproteins

In recent years it has been confirmed that the consumption of olive oil prevents the oxidation of biomolecules owing to its monounsaturated fatty acids (MUFA) and phenolic content. The main objective of the study was to develop an ultra‐high‐performance liquid chromatography (UHPLC) tandem mass spectrometry (MS/MS) method for the determination of phenolic compounds in human high‐density lipoprotein (HDL) samples. At the same time, the influence of olive oil consumption on the phenolic metabolite levels was evaluated in a European population. The participants were 51 healthy men, aged 20–60. They were randomized to two consecutive intervention periods with the administration of raw olive oil with low and high polyphenolic content. The UHPLC‐MS/MS analytical method has been validated for hydroxytyrosol and homovanillic acid in terms of linearity (r² = 0.99 and 1.00), repeatability (5.7 and 6.5%) reproducibility (6.2 and 7%), recovery (98 to 97%), limits of detection (1.7 to 1.8 ppb) and quantification (5.8 and 6.3 ppb).The levels of the studied metabolites increased significantly after high polyphenolic content virgin olive oil ingestion (p <0.05) compared with lowpolyphenolic content olive oil. Virgin olive oil consumption increases the levels of phenolic metabolites in HDL and thus provides human HDL with more efficient antioxidant protection. Copyright © 2014 John Wiley & Sons, Ltd.     

Quantification of astaxanthin in shrimp waste hydrolysate by HPLC

In the present study, a simple and rapid reversed-phase HPLC method for the determination of astaxanthin in shrimp waste hydrolysate has been developed and validated. The analytical procedure involves the direct extraction of astaxanthin from the lipid fraction with methanol. The analytical column, SS Exil ODS, was operated at 25C. The mobile phase consisted of a mixture of water:methanol:dichloromethane:acetonitrile (4.5:28:22:45.5 v/v/v/v) at a flow rate of 1.0 mL/min. Detection and identification were performed using a photodiode array detector (lambda(detection) = 476 nm). The proposed HPLC method showed adequate linearity, repeatability and accuracy.     

Rapid isolation,reliable characterization,and water solubility improvement of polymethoxyflavones from cold‐pressed mandarin essential oil

Polymethoxyflavones possess many biological properties, as lipid‐lowering, hypoglycaemic, anti‐inflammatory, antioxidant, and anticancer activities, therefore, they may be employed as nutraceuticals or therapeutic agents. The scarcity of pure polymethoxyflavones on the market as well as their low water solubility limited in vivo studies and the use of polymethoxyflavones as food or pharmaceutical supplements. Since mandarin peels are a rich source of polymethoxyflavones, tangeretin, nobiletin, sinensetin, tetra‐O‐methyl scutellarein, and heptamethoxyflavone were purified from a nonvolatile residue of a cold‐pressed mandarin essential oil using a multidimensional preparative liquid chromatographic system coupled with a photodiode array detector and a single quadrupole mass spectrometer. A new prototype, consisting of a nano‐liquid chromatography system coupled with an electron ionization mass spectrometer, was used for the characterization of the pure isolated molecules. Finally, due to the collection of highly pure nobiletin and tangeretin, the ability of 2‐hydroxypropyl‐β‐cyclodextrin to enhance the water solubility of both polymethoxyflavones was evaluated by phase solubility studies and Job's plot method.     

A convenient ultrasound‐assisted saponification for the simultaneous determination of vitamin E isomers in vegetable oil by HPLC with fluorescence detection

An efficient ultrasound‐assisted saponification was developed for simultaneous determination of vitamin E isomers in vegetable oil by high‐performance liquid chromatography with fluorescence detection. The samples were saponified ultrasonically with potassium hydroxide solution for only 7 min, then the analytes were extracted with ether. Vitamin E isomers were separated on a C₁₈ column at 25°C with a mobile phase of methanol/acetonitrile (81:19, v/v) at a flow rate of 0.8 mL/min. Fluorescence detection was operated at 290 nm of excitation wavelength and 327 nm of emission wavelength. Under the optimized conditions, good linearities over the range of 0.001–8.00 μg/mL (r > 0.999) were obtained. Mean recoveries of the method were 88.0–106%, with intra‐ and interday RSDs less than 11.8 and 12.8%, respectively. The detection limits and quantification limits of the method were 0.30–1.8 and 1.0–6.1 μg/kg, respectively. The recoveries of this method were much higher than that of the quick, easy, cheap, effective, rugged, and safe method and direct dilution method, but were similar to those of hot saponification. This proposed method provides reliable, simple, and rapid quantification of vitamin E isomers in vegetable oils. Five kinds of vegetable oils were analyzed, the quantification results were within the ranges reported by other authors.     

C_（60），C_（70）液相色谱分离方法的研究

较系统地考察了不同柱系统及不同流动相组成下Ｃ＿（６０）,Ｃ＿（７０）的保留规律。在实验的基础上,提出了分离Ｃ＿（６０）,Ｃ＿（７０）的最佳柱系统及流动相组成。并在此分离条件下,对高分子量的富勒烯组分进行了分离。     

高效液相色谱-光电二极管阵列检测法测定柴油中芳烃的类型

在采用美国试验与材料学会(ASTM) D6591标准方法测定柴油芳烃含量的过程中,通过光电二极管阵列检测器(PDAD)检测得到的色谱保留时间值及光谱特征吸收曲线,观察柴油中各类芳烃在极性氨基柱上的分离情况;用PDAD检测器考察了根据ASTM D6591确定的反冲洗时间点B对分析结果的影响,结果发现其允许的变化范围为B±0.2 min。在单环芳烃和双环芳烃分界不明显时,用PDAD检测器可以确定其切割点。     

Estimating the Analytical Performance of Raman Spectroscopy for Quantification of Active Ingredients in Human Stratum Corneum

Confocal Raman microscopy (CRM) has become a versatile technique that can be applied routinely to monitor skin penetration of active molecules. In the present study, CRM coupled to multivariate analysis (namely PLSR—partial least squares regression) is used for the quantitative measurement of an active ingredient (AI) applied to isolated (ex vivo) human stratum corneum (SC), using systematically varied doses of resorcinol, as model compound, and the performance is quantified according to key figures of merit defined by regulatory bodies (ICH, FDA, and EMA). A methodology is thus demonstrated to establish the limit of detection (LOD), precision, accuracy, sensitivity (SEN), and selectivity (SEL) of the technique, and the performance according to these key figures of merit is compared to that of similar established methodologies, based on studies available in literature. First, principal components analysis (PCA) was used to examine the variability within the spectral data set collected. Second, ratios calculated from the area under the curve (AUC) of characteristic resorcinol and proteins/lipids bands (1400–1500 cm⁻¹) were used to perform linear regression analysis of the Raman spectra. Third, cross-validated PLSR analysis was applied to perform quantitative analysis in the fingerprint region. The AUC results show clearly that the intensities of Raman features in the spectra collected are linearly correlated to resorcinol concentrations in the SC (R² = 0.999) despite a heterogeneity in the distribution of the active molecule in the samples. The Root Mean Square Error of Cross-Validation (RMSECV) (0.017 mg resorcinol/mg SC), The Root Mean Square of Prediction (RMSEP) (0.015 mg resorcinol/mg SC), and R² (0.971) demonstrate the reliability of the linear regression constructed, enabling accurate quantification of resorcinol. Furthermore, the results have enabled the determination, for the first time, of numerical criteria to estimate analytical performances of CRM, including LOD, precision using bias corrected mean square error prediction (BCMSEP), sensitivity, and selectivity, for quantification of the performance of the analytical technique. This is one step further towards demonstrating that Raman spectroscopy complies with international guidelines and to establishing the technique as a reference and approved tool for permeation studies.     

植物中酞酸酯的分析测定研究

建立了二氯甲烷超声提取、小粒径硅胶住色谱项分离、UV-HPLC测定植物中酞酸酯的方法,简便、快速,可使酞酸酯与杂质有效分离,回收率为85％～101％。用于实际植物样品中酞酸酯的测定,结果满意。     

Melodamide A from Melodorum fruticosum — Quantification using HPLC and one‐step‐isolation by centrifugal partition chromatography

Melodamide A, a phenolic amide from the leaves of Melodorum fruticosum Lour., has previously shown pronounced anti‐inflammatory activity. In order to rapidly isolate larger quantities for biological testing, a fast, one‐step isolation method by centrifugal partition chromatography was developed within this study. Fractionation of the dichloromethane extract was performed with a two‐phase solvent system consisting of n‐hexane, ethyl acetate, methanol, and water (3:7:5:5, v/v), leading to the isolation of melodamide A with a purity of >90% and a yield of 6.7 w% within 32 min. The developed method can also be used in dual mode for the enrichment of further constituents like flavonoids or chalcones. In order to support the centrifugal partition chromatography method development, additionally, a high‐performance liquid chromatography method was established and validated to determine quantities of melodamide A in plant material and crude extracts. Analysis of M. fruticosum leaves and a dichloromethane extract obtained from this plant material showed a total melodamide A content of 0.19 ± 0.008 and 8.9 ± 0.249 w%, respectively.