电膜萃取-光度法测定食品中的砷

应用电膜萃取-紫外-可见分光光度法测定食品中砷。对影响实验的参数进行优化:有机溶剂为邻苯二甲酸二异壬酯在正辛醇溶液中体积分数2.5%、电压70 V、萃取时间15 min、接受相溶液pH 13、搅拌速率700 r/min。砷的检出限为1.5μg/L,回收率为96%~104%,相对标准偏差(n=5)为0.1%~3.6%。本方法具有选择性好、操作简单、成本低等特点,可用于食品中总砷的分析。     

Rapid and Sensitive Determination of L-carnitine and Acetyl-L-carnitine in Liquid Milk Samples with Capillary Zone Electrophoresis Using Indirect UV Detection

The purpose of this study was to establish a new capillary zone electrophoresis method with indirect UV detection for determining the concentration of L-carnitine and acetyl-L-carnitine in liquid milk samples. Orthogonal experimental design was applied to arrange and optimize the experimental conditions. Under selected conditions (using melamine as the additive), both L-carnitine and acetyl-L-carnitine could be detected in 6 min, with satisfied reproducibilities (RSD% of migration times <0.8%), linearities (r ² > 0.995), recoveries (>90%), and relative low LODs (3.0 and 5.0 μmol/L for L-carnitine and acetyl-L-carnitine, respectively). The proposed method was successfully applied to the assay of nine brands of bovine milk samples and shows potential for analyzing L-carnitine and acetyl-L-carnitine in other biosamples.     

毛细管电泳法分析贝类食品中的软骨藻酸

为监测贝类食品的食用安全，建立了毛细管电泳/紫外检测法定量测定贝类食品中软骨藻酸的分析方法，结果表明：软骨藻酸在0.2～50μg/mL范围内具有良好的线性关系，相关系数r=0.9990；RSD=2.56%，方法检出限为0.034μg/g，在3个水平上对实际样品进行标准添加，回收率分别为96.80%，97.10%和96.85%，该方法简单，灵敏，高效，成本低，对记忆损失性贝类毒素的检测和监控具有重要意义。     

A Direct and Sensitive Analysis Method for Biogenic Amines in Dairy Products by Capillary Electrophoresis Coupled with Contactless Conductivity Detection

A capillary electrophoresis method coupled to contactless conductivity detection was developed for the quantitative determination of biogenic amines. Complete resolution of five biogenic amines, which are mostly found in dairy products, were performed in less than 6 min. Separation electrolyte composition was selected as 500 mM α-hydroxyisobutyric acid (HIBA) at pH 2.05. The detection limits of the method for biogenic amines were found between 0.041 and 0.098 mg/L. The precisions for the corrected peak areas were calculated as between 2.35 and 4.25% RSD. The applicability of the method was demonstrated by analyzing biogenic amines in the cheese, yoghurt, and kefir samples. The method does not require any pre-concentration and derivatization steps and can be applied as a simple, rapid, and precise method for the direct determination of biogenic amines in food samples.     

Simultaneous Determination of Seven Plant Growth Regulators in Melons and Fruits by Modified QuEChERS Coupled with Capillary Electrophoresis

A capillary electrophoresis method for the simultaneous determination of seven plant growth regulators including gibberellic acid, abscisic acid, 3-indole acetic acid, 3-indolepropionic acid, 3-indolebutyric acid, 2,4-dichlorophenoxyacetic acid, and 2-methyl-4-chlorophenoxyacetic acid in melons and fruits was established and validated. The samples were ultrasonically extracted with acidified acetonitrile and then dehydrated. The resulting solution was purified with modified QuEChERS method, and then dried-up under weak nitrogen flow, and the residue was redissolved with methanol-water (1:4, v/v) as sample solution. The electrophoretic separation was performed in an uncoated fused-silica capillary with borax buffer (pH 10.5) containing 29% of ethanol as the running buffer. The running voltage was 25 kV with the column temperature of 30 °C. The linear ranges of gibberellic acid, abscisic acid, and 2-methyl-4-chlorophenoxyacetic acid were from 0.10 to 8.0 μg/mL, while the others were from 0.05 to 4.0 μg/mL with the correlation coefficients greater than 0.997. The limits of detection and the limits of quantification of the method were in the range of 1.54–5.76 and 5.12–19.2 μg/kg, respectively. The recoveries of the method ranged from 69.0 to 109% with the relative standard deviations ranging from 2.01 to 15.4%. The proposed method has been successfully applied to the determination of plant growth regulator residues in 15 melon and fruit samples, and gibberellic acid and abscisic acid were detected in the samples.     

毛细管电泳-电化学发光分离检测饮料中L-精氨酸

基于L-精氨酸(L-Arginine)对三联吡啶钌(Ru(bpy)32+)在铂电极上的电致发光信号的增敏作用,建立一种测定L-精氨酸的毛细管电泳-电化学发光分离检测新方法。考察了检测电位、吡啶钌浓度、进样高压和进样时间、分离高压、运行缓冲液浓度及pH值等试验参数对L-精氨酸分离度及发光强度的影响,结果表明在最佳试验条件下,检测电位1.15V,Ru(bpy)32+浓度7mmol/L,进样条件8s×10kV,分离高压14kV,运行缓冲液pH8.5,浓度40mmol/L,可在400s内实现对L-精氨酸的分离检测,线性范围为5.74μmol/L～2.53mmol/L(R=0.9995),检出限(S/N=3)为1.38μmol/L。对样品进行测定,5次连续进样的迁移时间和峰高的RSD分别为0.33%和1.96%。本法已成功用于饮料中L-精氨酸的检测。     

高效毛细管电泳同时检测荸荠中的4种黄酮类物质

采用毛细管电泳法分析荸荠中的黄酮类化合物,测定了芦丁、槲皮素、山奈酚和绿原酸的含量。研究了缓冲液的种类、离子浓度、pH值、分离电压和运行温度等一系列电泳参数,得出优化的电泳条件为:缓冲液为20mmol/L磷酸二氢钾-20 mmol/L硼砂(pH 7.8),紫外检测波长202 nm,分离电压24 kV,运行温度30℃。在此条件下,上述4种物质在7 min内即可分离,并在3.125～100 mg/L内有良好的线性关系,相关系数R2均在0.999以上,相对标准偏差(RSD):迁移时间为0.78%～0.98%;峰面积为6.5%～8.6%。在5,10,20 mg/kg的添加水平下,4种物质的加标回收率为80%～98%。该方法简便、快速、重现性好,可推广应用于植物中4种黄酮类物质的同时检测。     

Study on a Molecularly Imprinted Solid-Phase Extraction Coupled to Capillary Electrophoresis Method for the Determination of Trace Trichlorfon in Vegetables

How to determine the pesticide residues in vegetable is an urgent problem. In this study, we reported a new method of solid-phase extraction coupled to capillary electrophoresis (SPE–CE) based on a molecularly imprinted polymer (MIP) for determination of trace trichlorfon. The electrophoretic conditions and factors which affected the molecularly imprinted solid-phase extraction were optimized. Under optimal conditions, the linear ranges of the calibration graph were 0.1 μg/L to 10 mg/L. The limit of detection (LOD) and method quantitation limit (MQL) were 4.9 and 16.2 μg/kg, respectively. With a flow rate of 2.5 mL/min for 50 mL loading, an enrichment factor of 160 was obtained. The relative standard deviation (RSD) for five replicate extractions of 0.01 mg/L trichlorfon standard solution was 4.5 %. The blank cucumber, lettuce, and radish samples spiked with trichlorfon at three levels were extracted and determined by this presented method with recoveries ranging from 77.6 to 93.2 %. Moreover, this proposed methodology was successfully applied to the quantitative detection of the trichlorfon residues in the leek samples, and the results were in good agreement with that obtained by the gas chromatography method.     

Matrix Solid-Phase Dispersion Extraction and Capillary Electrophoresis Determination of Tetracycline Residues in Milk

A capillary zone electrophoresis method was proposed for simultaneous detection and quantification of three tetracycline antibiotics in commercial milk samples, i.e., tetracycline, oxytetracycline, and doxycycline. The influences of the electrolyte composition, pH, as well as temperature and applied voltage on separation were investigated. The optimal running buffer was 30 mM Na₂HPO₄ and 1 mM EDTA at pH 11.5, with 3 s hydrodynamic injection, 25 kV applied voltage, and UV detection at 268 nm. Matrix solid-phase dispersion procedure was used for sample pretreatment. Several solid support materials were investigated, and silica with bonded C₁₈ chains (C₁₈) was used as sorbent. Electrophoretic analysis was completed in less than 6 min, with LODs ranging from 0.0745 μg/mL for oxytetracycline to 0.0808 μg/mL for doxycycline. The recoveries obtained were between 93.4% and 102%.     

毛细管电泳-电化学发光法测定腐胺与亚精胺

基于葡萄酒发酵产生的生物胺会影响人的健康,且腐胺与亚精胺均可明显增强三联吡啶钌[Ru(bpy)32+]的电化学发光强度,建立一种以直径500μm的Pt盘为工作电极的毛细管电泳-电化学发光法测定腐胺与亚精胺含量的分析方法;该方法具有灵敏度高、线性范围广、分离效率高、分析速度快等特点。实验获得的优化条件为,检测电位:1.15 V;Ru(bpy)32+浓度5 mmol/L(pH=9.5);进样时间10 s;进样高压10 kV;运行高压:13 kV;运行缓冲液:pH9.5050 mmol/L磷酸盐缓冲溶液。结果表明:在最优条件下,腐胺在0.1 mmol/L～4 mmol/L浓度范围内与发光强度呈良好的线性关系,相关系数为0.994 9,检出限为(S/N=3)为0.1 mmol/L;亚精胺在0.05 mmol/L～2 mmol/L浓度范围内与发光强度呈良好的线性关系,相关系数为0.992 5,检出限为(S/N=3)为0.05 mmol/L。用该方法对葡萄酒样品中的腐胺与亚精胺进行了平行测定,其中亚精胺的迁移时间和峰高的相对标准偏差(RSD)分别为0.13%和7.29%,样品中没有腐胺。     

毛细管电泳-电化学发光法测定荷叶中荷叶碱与莲子心中莲心碱含量

建立毛细管电泳-电化学发光法同时测定荷叶中荷叶碱与莲子心中莲心碱含量的方法。对三联吡啶钉(Ru(bpy)_3~(2+))溶液浓度、检测电位、磷酸盐缓冲液浓度和pH值、进样时间和分离电压等实验条件进行考察和优化。结果表明,在检测电位为1.20 V,运行缓冲液为10 mmol/L磷酸盐缓冲液(pH 5.74),5 mmol/L Ru(bpy)_3~(2+)溶液,检测池内磷酸盐缓冲液浓度为60 mmol/L(pH 8.30),进样电压为8 kV,进样时间为10 s,分离电压为13 kV,荷叶碱检出限为7.7×10~(-7)mol/L(R_(SN)-3),莲心碱检出限为7.8×10~(-7)mol/L(R_(SN)-3)。对浓度为6.8×10~(-5)mol/L荷叶碱和3.1×10~(-5)mol/L莲心碱的标准品溶液进行5次平行测定表明:荷叶碱峰面积的相对标准偏差(relative standard deviation,RSD)为3.76%,迁移时间RSD为0.83%;莲心碱峰面积RSD为4.28%,迁移时间RSD为1.37%。该方法可用于测定荷叶中的荷叶碱与莲子心中莲心碱含量。     

毛细管电泳测定乳酸发酵液中有机酸

运用毛细管区带电泳模式,在磷酸缓冲液中成功地分离了苹果酸、甲酸、乙酸、丙酸、琥珀酸、酒石酸、柠檬酸、乳酸、草酸9种有机酸。研究了缓冲液浓度、pH值、电泳电压、检测波长等因素对分离的影响,并对实际发酵液进行分析测定,加标回收率为97.5%～107.1%。该方法简便、快速、准确,适于整个发酵过程条件的优化及发酵产物的监控工作。     

离子液体-超声辅助萃取-高效液相色谱测定桑叶中黄酮

目的:建立以离子液体1-丁基-3-甲基咪唑溴化盐([BMIM]Br)为萃取剂,结合超声辅助萃取,利用高效液相色谱法同时分离测定桑叶中的桑色素、槲皮素和山奈酚3种黄酮的方法。方法:采用Phenomenex C18色谱柱(250mm×4.6mm,5μm);流动相为甲醇-0.1%磷酸溶液,采用梯度洗脱;流速1.0mL/min;紫外检测波长365nm;柱温为34℃。结果:该方法对桑色素、槲皮素和山奈酚分别在0.0065～130、0.0064～128、0.0042～84μg/mL范围内线性关系良好,相关系数(r)均大于0.9998,检出限(RSN=3)依次为0.99、1.31、0.64ng/mL;样品回收率为90.00%～95.31%。结论:本法操作简单快速、定量准确、灵敏度高、成本低、且对环境友好,为桑叶中黄酮化合物的检测及分离提供了一个有效的科学方法。     

Determination of 6-Benzylaminopurine in Bean Sprouts by Capillary Electrophoresis Compared with HPLC

A simple capillary electrophoresis (CE) method based on solid-phase extraction (SPE) for the analysis of 6-Benzylaminopurine (6-BAP) was developed. Separation conditions were obtained in the sodium phosphate buffer solution (20 mM and pH 2.0), with 25 kV applied voltage and UV detection at 274 nm. Amiloride hydrochloride (AM) was used as an internal standard. Under the selected conditions, electrophoretic analysis was completed in less than 7 min, with LOD and LOQ of 19 and 65 ng mL^?1 for 6-BAP. The method was successfully applied to determine 6-BAP in bean sprouts with RSD lower than 3.6 % and the recoveries from 95.0 to 103.4 % for the spiked samples. Comparative experiments were also carried out with HPLC-UV method described in National Standards of People’s Republic of China. The validation results of the two methods are comparable, but the proposed CE method was found to be simple, rapid, allowing separation and analyte quantification in shorter time, and the reagent consumption was reduced.     

面粉中的溴酸盐离子色谱-串联质谱法分析

建立面粉中的溴酸盐离子色谱-串联质谱分析方法。样品以水浸泡,超声波提取,用C18固相萃取小柱净化,离子色谱-串联质谱仪测定。在10.0～50.0μg/kg添加水平内,平均回收率在82.1%～86.6%之间,变异系数在4.5%～7.3%之间。以RSN=3计算,方法检出低限为3μg/kg。结果表明,该法回收率稳定、基质干扰少、简便、灵敏、准确,适用于面粉中溴酸盐的确证分析测定。     

毛细管电泳-电化学检测法测定鸡蛋中残留四环素类抗生素

本研究运用毛细管电泳-电化学检测法(CE-ED)对鸡蛋中残留的四环素(TC)、土霉素(OTC)进行快速测定分析。考察了缓冲液浓度和pH值、TW-20、盐浓度、分离电压、进样时间、检测电位等因素对分离检测的影响。结果表明,TW-20体积分数为2.5%时,在检测电位为1.2V,20mmol/L缓冲溶液(pH2.6),25kV分离电压,进样8s的条件下,TC和OTC有很好的分离效果。TC和OTC的线性范围分别为:2.0×10-6～5.0×10-4g/ml和8.0×10-6～3.0×10-4g/ml,检测限分别为1.9×10-8g/ml和4.1×10-8g/ml。     

毛细管电泳-电化学发光分离检测饮料中L-赖氨酸

目的:根据L-赖氨酸(L-lysine)具有增强三联吡啶钌(Ru (bpy)32+)电化学发光信号的特性,建立一种毛细管电泳-电化学发光分离检测L-赖氨酸的新方法.方法:研究检测电位、Ru(bpy)32+浓度、进样时间、进样电压、分离电压和缓冲液pH等试验参数对L-赖氨酸检测的影响.结果:在最佳试验条件下,检测电位1.13 V;Ru( bpy)32+浓度7 mmol/L(pH 8.5);进样时间10s;进样电压12 kV;分离电压12 kV;磷酸盐缓冲液pH 8.5,8 min内可实现L-赖氨酸的分离检测,线性范围3.00～87.00 μg/mL,相关系数R=0.9991,检出限(S/N=3)为0.21μg/mL.对样品进行测定,电化学发光强度和迁移时间的RSD分别为3.85％和0.66％(n=6).结论:本法已成功用于饮料中L-赖氨酸的检测,结果令人满意.     

低聚异麦芽糖产品中主要组分的毛细管电泳分析方法

在未涂渍的石英毛细管中 ,以 75mmol/L硼砂 (pH 1 0 5 )为运行电解质 ,在检测波长 2 1 4nm、分离电压 1 5kV下对低聚异麦芽糖的主要组分的α 萘胺衍生物进行了快速分离测定。结果表明 ,该方法重现性好 ,迁移时间和峰面积的相对标准偏差分别在 0 5 %和 2 0 %以内。异麦芽糖、异麦芽三糖、潘糖浓度在 0 0 0 5～ 1 0 0 0mg/mL范围内 ,含量均与其峰面积之间呈现良好的线性关系。该法灵敏度高 ,成本低 ,为测定低聚异麦芽糖产品中主要组分提供了一种高效快速的方法     

毛细管电泳法检测婴幼儿奶粉中乳铁蛋白的质量分数

建立了准确简便的测定婴幼儿奶粉中乳铁蛋白质量分数的方法,样品经脱脂、酸法去除酪蛋白和硫酸铵沉淀富集、纤维素滤膜过滤净化等方法进行预处理,选择直径为50μm,有效长度为57 cm的未涂层毛细管柱进行检测,缓冲溶液为浓度40 mmol/L的硼酸盐/磷酸盐(pH值为9.5),浓度为50 mmol/L的SDS,浓度为20 mmol/L的Brij35,体积分数4%异丙醇,浓度为30 mmol/L硫酸钠,工作电压为18 kV,检测波长为200 nm。结果显示标准曲线相关系数为0.9992;平均回收率为92.8%,6次样品测定RSD为2.4%。     

高效毛细管电泳法检测橘皮中橙皮苷的含量

应用毛细管电泳法对橘皮中橙皮苷的含量进行了检测,研究了缓冲液的种类、缓冲液的浓度、缓冲液的pH值以及分离电压等对橙皮苷测定的影响。在pH8.0的150 mmol/L硼砂缓冲液、12 kV分离电压下,橙皮苷的测定效果最佳。毛细管电泳法测定橙皮苷的最低检测限为1.25μg/mL,加样回收率是99.75%,相对标准误差是1.98%。