高效液相色谱-荧光检测法测定牛奶中氯霉素的残留量

建立了对牛奶中氯霉素的残留量进行检测的高效液相色谱-荧光检测方法。氯霉素还原后在温和条件下与荧光胺发生衍生化反应,采用十八烷基键合硅胶固定相,以乙腈/四氢呋喃/0.02 mol/L醋酸钠-醋酸缓冲液(pH 6.0)(体积比为16∶8∶76)为流动相,流速1.0 mL/min,柱温40 ℃,荧光检测激发波长为410 nm,发射波长为508 nm。在上述实验条件下,氯霉素检测的线性范围为0.4~800 μg/L (r2=0.9999),检出限为0.2　μg/L。当空白样品中氯霉素添加水平为2~40 μg/L时,该方法的回收率为66.6%~92.8%,相对标准偏差为4.5%~9.4%。该方法适用于牛奶中氯霉素痕量残留的监测,具有干扰小、选择性好、灵敏度高等优点。     

邻苯二甲醛衍生荧光法测定牛奶中的苄青霉素残留

长期饮用含高浓度苄青霉素残留的牛奶可带来严重的健康问题,建立一种可对其进行灵敏检测的方法是必要的.苄青霉素在酸性条件下的水解产物之一是青霉胺,与邻苯二甲醛衍生后可生成具有强荧光的1-硫代2-烷基异吲哚衍生物,据此建立了荧光分光光度法测定苄青霉素的新方法.在水解时间为1 h、衍生反应体系pH为10.0、衍生试剂用量为40 μL、衍生反应时间为15 min的最佳测定条件下,线性动态范围为2.0 ～500 μg/L,检出限为1.3 μg/L,样品的平均加标回收率为89.1%,方法可满足我国对牛奶中苄青霉素残留的限量要求.     

对虾中氯霉素残留的分析方法研究

用液相色谱-质谱法定量检测对虾中微量的氯霉素残留。采用乙酸乙酯超声提取对虾组织中的氯霉素残留,以甲醇为流动相,选择m／x321／152为氯霉素的检测离子对,用多反应监测(MRM)技术测定。氯霉素流出液相色谱的时间在1．5min以内;线性范围是0．28-28．0μg／L;线性相关系数为0．99991。对虾中氯霉素的定量检测下限是0．07μg／kg,平均回收率在89％以上。该方法快速、灵敏,定量范围宽,检验结果准确可靠,应用性强。     

荧光衍生法测定枸橼酸喷托维林的含量

采用衍生化反应,建立了荧光分光光度法测定枸橼酸喷托维林的新方法.对影响荧光强度的衍生体系、反应温度、反应时间、产物稳定性等进行了研究.实验表明在激发波长和发射波长分别为367nm和457nm时,荧光强度与枸橼酸浓度在8.0×10-7～1.0×10-4g/mL范围内呈良好的线性关系,并对1.0×10-6g/mL枸橼酸喷托维林溶液进行6次平行测定,相对标准偏差为0.31%,检出限达1.5×10-8g/mL.本法用于枸橼酸喷托维林片剂含量的测定,结果与药典法测得值相符合.     

微波快速萃取-荧光衍生化HPLC-MS测定不同品种金银花中游离脂肪酸

建立了金银花中游离脂肪酸的微波快速萃取方法,采用柱前荧光衍生化法,测定了金银花中16种长链饱和与不饱和游离脂肪酸的含量。微波萃取功率800 W,溶剂V(氯仿):V(甲醇)=1:1,70℃萃取8 min,萃取率>98.8%。采用酸性乙腈/水流动相在反向C8色谱柱上进行梯度洗脱,HPLC荧光检测波长为505 nm,在线联用质谱辅助鉴定(APCI-MS),提高了检测的准确度。方法检出限在0.366~2.58μg/L之间,回收率88.3%~107.6%。     

应用新荧光增强剂荧光胺测定GSH

研究了荧光胺(Fluram)与还原型谷胱甘肽(GSH)反应产物的光学性质;发现GSH Fluram体系在480nm处有强荧光峰,其荧光强度与GSH的浓度有良好的线性关系,并由此建立了GSH的荧光分析方法,其线性范围为4.2×10-7～9.8×10-6mol L,检出限为4.2×10-7mol L;该方法应用于食品中黄瓜、鸡肝中GSH的测定,并与常用的HPLC方法进行了对比,所建立的方法简便快速,可靠性高。     

化学发光酶免疫法测定水产品中残留氯霉素

1引言 氯霉素（CAP）能抑制人体骨髓造血功能，引起人类再生障碍性贫血，粒状白细胞缺乏症，新生儿，早产儿灰色综合症等疾病。我国禁止在动物饲料中使用。免疫分析法操作简单，快速，通常用来大规模筛选样品。     

氨基酸柱前衍生化的3种新荧光试剂的光谱特性及高效液相色谱研究

合成了３种新的荧光标记试剂：吖啶－Ｎ－乙酰氯，咔唑－９－乙酰氯和咔唑－９－丙酰氯。它们的最大发射降激发波长分别为４３０ｎｍ，３６８ｎｍ，和３６５ｎｍ。３种衍生化试剂与氨基酸形成的衍生物在ｐＨ６．５的条件下结合梯度洗脱程序在Ｃ１８反相柱上对色谱条件进行了优化。     

化学衍生法应用于生物多胺的HPLC荧光检测

介绍了在高效液相色谱荧光衍生法分析多胺中常用的几类荧光衍生试剂及其应用,对近年多胺分析中的高效液相色谱荧光衍生方法进行了综述。     

伏安免疫法检测牛奶中氯霉素残留

为探索用于现场检测牛乳中氯霉素(CAP)残留的高灵敏度及特异性强的免疫传感器方法,本实验在制备CAP单克隆抗体的基础上,以卵清蛋白-氯霉素(OVA-CAP)偶联物为包被抗原,并将其包被到聚苯乙烯反应板上;在孵育反应中,样品中的CAP与OVA-CAP竞争结合CAP单克隆抗体,洗涤后加入碱性磷酸酶(ALP)标记的二抗,经再次孵育及洗涤后加入对硝基苯磷酸(pNPP)底物液;反应终止后用线性导数伏安法记录pNPP水解产物的氧化峰电流。实验结果表明,用免疫传感法测试CAP的灵敏度高于传统的间接竞争酶联免疫吸附法(ELISA)。该方法检测CAP的检出限为0.064μg/L;检测线性范围为0.15~600μg/L,测试牛奶样品的平均回收率为89.8%。另外,由于免疫电化学传感器体积较小,便于携带,操作简单,可实现牛乳样品中CAP残留的现场检测。     

A new cyano-substituted fluorescamine superior to its original form as a fluorescent probe for amino acid detection

Synthesis and spectral study of two new cyano-substituted fluorescamine as the fluorescent probes for amino acid detection have been carried out comparing with the original fluorescamine. Of the three compounds, the derivative with a cyano group at the meta-position on the 4-phenyl group was found to be superior to the original one in the reactivity toward some amino acids as well as the fluorescence intensity of the adducts. The fluorescent amino acid adducts were also applied to the peroxyoxalate chemiluminescence system as the fluorophores, in which the derivative described above was found to be more effective also in chemiluminescence than the original one.     

Use of chiral derivatization for the determination of dichlorprop in tea samples by ultra performance LC with fluorescence detection

Dichlorprop is available for agricultural use as a chiral pesticide. In this study, the stereoselective determination of dichlorprop enantiomers in tea samples such as green, black, jasmine, and oolong was developed by ultra performance LC with fluorescence spectrometry after covalent chiral derivatization. The separation was achieved on an Acquity BEH C18 column with the mobile phase consisting of 0.1% formic acid in acetonitrile/water at a flow rate of 0.4 mL/min. In the covalent chiral derivatization using (S)‐(+)‐4‐(N,N‐dimethylaminosulfonyl)‐7‐(3‐aminopyrrolidin‐1‐yl)‐2,1,3‐benzoxadiazole, the peak resolution between the S and R‐dichlorprop enantiomers was 2.6. LODs and LOQs values were 10 and 50 ng/mL standard solution. The linearity of the calibration curves yielded the coefficients (r² > 0.99, ranging from 0.05 to 5 μg/mL) of determination of each of the dichlorprop enantiomers. SPE extraction was used for the sample preparation of dichlorprop in various tea samples. Recoveries were in the range of 82.4–97.6% with associated precision values (within‐day: 82.4–95.8%, n = 6, and between‐day: 83.7–97.6% for 3 days) for repeatability and reproducibility. Based on this result, our method has been proven to be highly efficient and suitable for the routine assay of dichlorprop enantiomers in various tea samples. We propose that the ultra performance LC assay after covalent chiral derivatization would be the renewed tools in the era of chiral stationary platform for chiral pesticide residues in foods.     

Liquid chromatographic determination of aniline and derivatives in environmental waters at nanogram per litre levels using fluorescamine pre-column derivatization

Summary Fluorescamine (fluram) has been used as a fluorogenic compound for pre-column derivatization of aniline and some derivatives. Anilines were derivatized with fluram in citrate buffer media (pH 5.5) to form pyrrolinones. The highly fluorescence pyrrolinones were isolated and pre-concentrated by solid phase extraction. A reversed phase, Spherisorb RP-8 column and tetrahydrofuran: water:formic acid (42:56:2) mobile phase was used for separation. Detection method was by a sensitive fluorimetric method and quantitation was at 395 and 495 nm. The various parameters such as reaction conditions between anilines and fluram, solid phase extraction and chromatographic separation were optimized. Calibrations were linear over the range considered with excellent correlation coefficients (r>0.999). Relative standard deviations are less than 2.5 % and detection limits for aniline,p-toluidine, 4-chloroaniline and 4-bromoaniline were 6, 30, 6 and 8 ng L⁻¹, respectively. This method has been used successfully for the determination of anilines in environmental waters.     

Effect of background derivatization on the signal enhancement of pesticide residues extracted from edible oils

The effect of background derivatization on the signal enhancement of pesticide residues extracted from edible oil samples was studied by GC with negative chemical ionization MS. The analytes were extracted by a solvent extraction process, and the extract was subjected to rapid low‐temperature fat precipitation. The residual fatty acids were silylated by derivatization with N,O‐bis(trimethylsilyl)trifluoroacetamide. The chromatograms obtained from the derivatized samples showed higher signal intensity and lower detection levels when compared to the direct analysis without derivatization. The sensitivity levels of the method are either better or comparable to that of previously reported methodologies. The LODs of the analyzed organochlorine, organophosphorus, and synthetic pyrethroid residues in sunflower, rice bran, and ground oil samples were in the range of 0.02–0.5 ng/g, and the LOQs were in the range of 0.1–2 ng/g. The intraday and interday accuracies were in the range of 81–116% with RSDs less than 14%. The recoveries obtained were in the range of 53–89% with the RSD values less than 13% for all the studied pesticide residues.     

Derivatisation of sympathomimetics with primary amino groups on thin-layer plates by spotting the sample spots with fluorescamine

Summary A method has been developed for the quantitative determination of sympathomimetics containing a primary amino group on thin-layer plates with fluorescamine. The reaction is carried out by spotting fluorescamine solution in acetone on top of the sample spots. The fluorescamine derivatives are subsequently separated using appropriate solvent systems. Spotting a buffer before reaction and spraying with triethanolamine after development is unnecessary. The consumption of reagent is extremely low. For ten thin-layer plates with ten sample spots per plate only 0.2 cm³ reagent solution are needed. The method has been applied to the quantitative determination of some compounds with primary amino groups in pharmaceutical preparations.Dedicated to Prof. Dr. G. Zigeuner on his 60^th birthday.     

Rapid determination of sulphonamides in milk using liquid chromatographic separation and fluorescamine derivatization.

A simple and selective method is presented for the multiple residue determination of eight sulphonamides in consumers' milk. The drugs are sulphisomidine (ID), sulphadiazine (DZ), sulphamerazine, sulphadimidine, sulphamonomethoxine, sulphamethoxazole, sulphadimethoxine and sulphaquinoxaline (SQ). The milk sample was deproteinized with the same volume of 2 M hydrochloric acid and filtered. A 1-ml volume of the filtrate was mixed with 1 ml each of 1.25 M sodium acetate solution and a buffer (pH 3.0) for derivatization with 0.6 ml of 0.02% fluorescamine solution in acetone. A high-performance liquid chromatographic analysis was carried out on a C18 column with a mobile phase of acetonitrile-2% acetic acid (3:5) at 55 degrees C using a fluorescence detector at an excitation wavelength of 405 nm and an emission wavelength of 495 nm. Average recoveries at fortification levels of 2, 5 and 10 ng/ml were 114%, 109% and 106%, respectively. Relative standard deviations were 1-4% at 10 ng/ml for ID, 5 ng/ml for DZ and SQ and 2.5 ng/ml for the other five sulphonamides. The method was applied to 25 milk samples and all appeared to be free from the drugs.     

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.     

新型活性炭纤维固相微萃取衍生化与GC-MS联用测定牛奶中的碘

优化了影响新型活性炭纤维衍生化固相微萃取(ACF-SPME)效率的萃取时间、萃取温度、解析时间、解析温度以及离子强度等主要条件。碘的检出限为0.1μg/L,线性范围为1~500μg/L,相对标准偏差(RSD%)为6.9%。方法用于牛奶样品分析,样品的加标回收率为86%。活性炭纤维与商用纤维相比,具有吸附量大,成本低,使用寿命长和耐高温等优点,是一种有发展前景的固相微萃取纤维。     

Improved determination of milk oligosaccharides using a single derivatization with anthranilic acid and separation by reversed-phase high-performance liquid chromatography

An improved analytical scheme for human milk neutral oligosaccharides determination was developed, in which, the oligosaccharides were pooled in two fractions (pools 1 and 2) after gel filtration, and then were quantitatively derivatized with a single fluorescent reagent, 2-anthranilic acid. Separation was by reversed-phase HPLC on an ODS-100Z column with a mobile phase of 50 mM ammonium acetate pH 4.0 and 150 mM citrate buffer pH 4.5 and monitored by a fluorescence detector at 360 nm excitation and 425 nm emission wavelengths. The method improved on the separation of neutral tetra- and hexa-saccharide isomers, namely, lacto-N-tetraose (LNT) and lacto-N-neotetraose (LNnT) as well as of lacto-N-difucohexaose I (LNDFH I) and lacto-N-difucohexaose II (LNDFH II). The separation of trisacccharide isomers, 3-fucosyllactose (3-FL) and 2′-fucosyllactose (2′-FL) was also successful. Limits of detection and quantification were in the range of 1–10 ng/l and 2–30 ng/l, respectively. The methods’ accuracy was good with its precision at <20% RSD and <1% RSD, respectively, for oligosaccharide concentration and retention time. The recoveries were in the range of 80–100%. This method was successfully applied to the separation and determination of representative neutral oligosaccharide contents in Samoa women milk.