基于亲水性可控棉线有效分离苏丹I和罗丹明B

近年来,食品安全问题引起了人们的广泛关注.非食用色素因价格低廉、着色能力强而被非法用于食品加工过程,严重威胁消费者生命健康.苏丹I和罗丹明B是食品加工中最常被滥用的两种典型非食用有机着色剂,进入人体后会在相应酶的作用下产生致癌物.高效液相色谱法是用于违禁色素分离检测的主要方法,但该方法所需仪器昂贵,专业程度高且操作繁琐,限制了其在色素鉴定中的应用.棉线作为一种低成本固定相已被用于有机色素的色谱分离,但是对于其亲疏水性在色素分离中的作用目前仍不清楚,也未见将该系统直接用于色素分离收集的报道.针对上述问题,本研究采用等离子体可控预处理的方式实现对棉线亲疏水性能的调控,并进一步探究了棉线亲疏水性在棉线基色谱分离和收集过程中的作用.在等离子体处理过程中,调整了棉线的缠绕方式、等离子体功率和暴露时间,并通过扫描电镜、接触角测试和线上液体流动实验对棉线内部结构以及棉线亲疏水性进行了表征.结果表明,等离子体处理并不影响棉线的加捻结构和纤维间空隙大小;棉线以"之"字形悬空缠绕在支架上可增大暴露面积,从而获得更高的亲水性能;棉线的亲水性高度依赖于等离子处理时间和仪器功率,在10.15 W的等离子机中处理8 min被证明是最佳处理参数,可使棉线具有最高的亲水性能.X射线光电子能谱分析(XPS)表明,经等离子体处理后棉线的含氧基团显著增多,这可能是棉线亲水性提高的原因.以乙醇/水溶液为展开剂,探究了棉线亲水性对色素分离的影响,发现棉线亲水性提高可以显著增强色素的分离效果.色素与棉线的结合力以及流动相在棉线上的流动能力可能是色素分离效果的决定性因素.在色素分离收集实验中,分别以乙醇/水溶液和甲酸/甲醇溶液作为展开剂对罗丹明B和苏丹I进行分离收集,并对不同阶段的洗脱液进行了紫外吸收光谱分析.在乙醇/水溶液体系中,两种色素虽然可先后通过棉线固定相,但在苏丹I洗脱液中仍然含有微量的罗丹明B;而在甲酸/甲醇溶液体系中,两种色素可以更有效地分离,且分离速度更快.综上,本研究揭示了亲水性在线基色谱系统中的关键作用,开发了一种简便、低廉和易于操作的线基色素分离方法,并将其用于非食用色素苏丹I和罗丹明B的有效分离和收集.本研究有望为高性能线基色谱分离系统的设计和构建提供理论指导,并进一步拓展线基流控分离方法的应用领域.     

使用气相色谱法和液相色谱法对六种尼泊金酯类进行分离测定

分别采用气相色谱法和液相色谱法,对六种尼泊金酯类同时进行分离测定,再比较两种方法的优缺点,可为测定食品、化妆品和医药中尼泊金酯类的含量提供方法参考。     

气相色谱法分析中色谱柱的选择

前言气相色谱法是近代重要的分析方法之一,它不仅能高效分离和快速分析,还能准确定性和定量测定,并易实现自动化。因此,目前,已被广泛应用于石油、化工、农业、医药、生化、食品、环保等领域。气相色谱法对于复杂体系具有强分离能力和高分     

用TLC／FID棒薄层色谱测定重质油的族组成方法的研究

建立了快速重质油族组成的薄层色谱／氢火焰（TCL/FID）法,用两种展开剂可将试样很好地分离成饱和烃、芳烃、胶质及沥青质三个组分。本方法与经典柱色谱分析方法分析结果非常吻合,具有很好的重复性和准确性。     

新疆维药刺糖化学成分研究

对新疆维药刺糖的化学成分进行系统分离纯化和结构鉴定。采用树脂、硅胶柱等色谱法分离化合物,用理化分析、元素分析和NMR分析等现代波谱技术和现代分析方法鉴定化合物的结构。从刺糖中分离得到了4个单体化合物,并鉴定其化学结构,4个化合物均为首次从该种植物中获得,为今后进一步研究其药效,开发和利用新疆药用植物资源提供基础研究资源。     

富勒烯C_(60)和C_(70)分离纯化研究进展

色谱法、重结晶法、化学络合法等是分离纯化富勒烯的主要方法。综述了近20年来富勒烯分离纯化方面的研究进展,对C60和C70的分离方法进行了阐述,同时展望了今后的工作。     

水和废水中氯苯的气相色谱分析方法研究

本文研究了水和废水中氯苯的萃取及分析方法。采用气相色谱法、大口径毛细管柱分离氯苯,以ECD进行检测,得到了良好的分离效果和较高的灵敏度,方法的检出限可达0.01mg/L。本方法完全能满足环境样品分析的要求。     

奥氮平有关物质的HPLC检查法研究

为研究奥氮平有关物质检查的HPLC分离方法,比较不同色谱柱、不同柱长和不同洗脱形式,其中3种色谱柱分别为C18柱(150 mm×4.6 mm×5 μm)、C8柱(150 mm×4.6 mm×5 μm)和C8柱(250 mm×4.6 mm×5 μm),洗脱形式分别为梯度洗脱和恒比例洗脱.杂质的分离个数依次为自建法(n=6)、美国药典法(USP,n=5)和国家药品标准法(WS,n=4);分离度USP法表现最佳(r=3.63),而WS法最差(r=1.38),但是WS法有最高的杂质检出灵敏度.综上结果表明,自建法具有分析时间较短、分离度较高、基线平稳、灵敏度较高等特点,为奥氮平有关物质限量检查的较好方法.     

磷脂的高效液相色谱分析

天然磷脂是含磷酸的类脂化合物,广泛存在于植物、动物及微生物体中,在工业生产、食品科学、医药学、生命科学等研究方面都有重要的应用。磷脂的研究手段多样,高效液相色谱在磷脂的分离、检测方面具有优势。本文结合近年来国内外高效液相色谱分离磷脂的研究报道,对高效液相色谱分离、检测磷脂的方法进行了分类、评价。     

猪肝中克伦特罗的测定─反相高效液相色谱法

本文介绍了一种简单、快速测定猪肝中克伦特罗的液相色谱检测方法,色谱保留、分离均优于C18分离体系,准确性和精密度满足检测要求需要。     

离子色谱法测定饮用水中常见阴离子

本文主要介绍离子色谱法检测饮用水中常见阴离子的方法。本方法采用瑞士万通的761型离子色谱仪。分离柱为METROSEPAnionDual2,淋洗液为2.0mmol/LNaHCO3和1.3mmol/LNa2CO3抑制液为20mmol/LH2SO4在测定范围内,F-、Cl-、NO2-、NO32-;-SO42-的峰面积和质量浓度呈线性关系,相关系数均大于0.999。回收率F-为101.5%,CL-O101.6%,NO2-为108.0%.NO32-为97.7%,SO42-为103.3%。相对标准偏差在0.7%-4.3%之间。     

Determination of iodide in seawater by ion chromatography

A simple and highly sensitive ion chromatographic method with UV detection was developed for iodide (I(-)) in seawater. A high-capacity anion-exchange resin with polystyrene-divinylbenzene matrix was used for both preconcentration and separation of iodide. Iodide in artificial seawater (salinity, 35‰) was trapped quantitatively (98.8 ± 0.6%) without peak broadening on a preconcentrator column and was separated with 0.35 M NaClO(4) + 0.01 M phosphate buffer (pH 6.1). On the other hand, the major anions in seawater, chloride and sulfate ions, were partially trapped (5-20%) and did not interfere in the determination of I(-). The detection limit for I(-) was 0.2 μg/L for 6 mL of artificial seawater. The present method was applied to determination of I(-) (ND - 18.3 μg/L) and total inorganic iodine (I(-) + IO(3)(-) - I, 50.0-52.7 μg/L) in seawater samples taken near Japan.     

强疏水性AS-15色谱柱测定茶叶中F-、Cl-、NO3-、PO43-、SO42-、BrO3-、Br-、NO2-的研究

建立了一种利用强疏水性分离柱,通过KOH梯度淋洗,同时测定茶叶中F-、Cl-、NO3-、PO43-、SO42-、BrO3-、Br-、NO2-的方法。采用沸水冲泡茶样,茶水比为1:50,时间为5 min,过滤后稳定30 min待测;样液经过活性炭净化,再用0.20μm滤膜过滤后待测。结果表明:8种无机阴离子色谱峰能达到完全的基线分离,且浓度与峰面积呈良好的线性关系,检出限均低于0.056mg/L,加标回收率为96.5%~105.1%,该法用于茶样中8种无机阴离子含量的测定,结果稳定且重复性较好。     

Counterionic Detection by ICP-AES for Determination of Inorganic Anions in Water Elution Ion Chromatography Using a Zwitterionic Stationary Phase

The analytical methods for the determination of inorganic anions by water elution ion chromatography using a zwitterionic column (C14SB-coated column) have been explored, where pure water was used as the mobile phase. In the present ion chromatography, the complicated peaks derived from various "ion pairs" appeared on the chromatogram when the sample solution contained several kinds of cations and anions. The chromatograms with the complicated peaks were simplified by using a preconditioning cation-exchange column. In the preconditioning column, various kinds of countercations of the analyte anions were converted to a particular kind of common cation, and thus all the analyte anions were separated as the common cation form. The more effective separation was achieved by converting to a divalent cation (Mg(2+)) form than a monovalent cation (Na(+)) form, because the anions paired with the divalent cation provided longer elution times than those paired with the monovalent cation. All the analyte anions separated as the common cation form were simply determined from their calibration curves drawn from conductivity detection. In addition, the counterionic determination of the anions was also attempted by using ICP-AES. The analyte anions were determined by measuring their countercations with ICP-AES, where the calibration curve of the countercation measured by ICP-AES could be used.     

高效毛细管电泳/电导检测法测定饮用水中的阴离子

本实验采用四乙烯五胺作为毛细管电泳的电渗流抑制剂,以10mmol/L Tris(三羟甲基氨基甲烷)+10mmol/L H3BO3(硼酸)+0.2mmol/L EDTA(乙二胺四乙酸)+0.2%(V/V)四乙烯五胺为电泳运行液,负高压分离(-15kV),电导检测,对饮用水中的Cl-、NO3-、SO42-三种阴离子进行了直接分离测定,并考察了分离电压,pH值,电解质溶液的组成及浓度,电渗流抑制剂,有机添加剂组成等对分离的影响。建立高效、快速的饮用水无机阴离子高效毛细管电泳/电导检测的分析方法。     

Latex-coated polymeric monolithic ion-exchange stationary phases. 1. Anion-exchange capillary electrochromatography and in-line sample preconcentration in capillary electrophoresis

A sulfonated methacrylate monolithic polymer has been synthesized inside fused-silica capillaries of diameters 50-533-microm i.d. and coated with 65-nm-diameter fully functionalized quaternary ammonium latex particles (AS18, Dionex Corp.) to form an anion-exchange stationary phase. This stationary phase was used for ion-exchange capillary electrochromatography of inorganic anions in a 75-microm-i.d. capillary with Tris/perchlorate electrolyte and direct UV detection at 195 nm. Seven inorganic anions (bromide, nitrate, iodide, iodate, bromate, thiocyanate, chromate) could be separated over a period of 90 s, and the elution order indicated that both ion exchange and electrophoresis contributed to the separation mechanism. Separation efficiencies of up to 1.66 x 10(5) plates m(-1) were achieved, and the monoliths were stable under pressures of up to 62 MPa. Another latex-coated monolith in a 250-microm-i.d. capillary was used for in-line preconcentration by coupling it to a separation capillary in which the EOF had been reversed using a coating of either a cationic polymer or cationic latex particles. Several capillary volumes of sample were loaded onto the preconcentration monolith, and the analytes (inorganic anions) were then eluted from the monolith with a transient isotachophoretic gradient before being separated by electrophoresis in the separation capillary. Linear calibration curves were obtained for aqueous mixtures of bromide, nitrite, nitrate, and iodide. Recoveries of all analytes except iodide were reduced significantly when the sample matrix contained high levels of chloride. The preconcentration method was applied to the determination of iodide in open ocean water and provided a limit of detection of 75 pM (9.5 ng/L) calculated at a signal-to-noise ratio of 3. The relative standard deviation for migration time and peak area for iodide were 1.1 and 2.7%, respectively (n = 6). Iodide was eluted as an efficient peak, yielding a separation efficiency of 5.13 x 10(7) plates m(-1). This focusing was reproducible for repeated analyses of seawater.     

Flame atomic absorption spectrometric determination of trace quantities of cadmium in water samples after cloud point extraction in Triton X-114 without added chelating agents

A new micell-mediated phase separation method for preconcentration of ultra-trace quantities of cadmium as a prior step to its determination by flame atomic absorption spectrometry has been developed. The method is based on the cloud point extraction (CPE) of cadmium in iodide media with Triton X-114 in the absence of any chelating agent. The optimal extraction and reaction conditions (e.g., acid concentration, iodide concentration, effect of time) were studied, and the analytical characteristics of the method (e.g., limit of detection, linear range, preconcentration, and improvement factors) were obtained. Linearity was obeyed in the range of 3-300 ng mL(-1) of cadmium. The detection limit of the method is 1.0 ng mL(-1) of cadmium. The interference effect of some anions and cations was also tested. The method was applied to the determination of cadmium in tap water, waste water, and sea water samples.     

Single-run capillary electrophoretic determination of inorganic nitrogen species in rainwater

A capillary electrophoretic (CE) method for the simultaneous determination of nitrate, nitrite, and ammonium ions has been developed. Direct (NO3-, NO2-) and indirect (NH4+) UV detection at 214 nm in conjunction with electromigration sampling from both ends of the capillary was used. The optimized separations were carried out in 10 mmol/L imidazole sulfate, 2 mmol/L 18-crown-6, and 0.02 mmol/L tetradecyltrimethylammonium hydroxide electrolyte (pH 4.0). The method permits excellent separation of three nitrogen species in only 4 min. A 1 x 10(-4) mol/L KBr solution was used as an internal standard to limit possible electrokinetic injection biases. Experimental results showed that the use of an anionic internal standard for cationic analytes and vice versa gives only slightly better precision than analysis with no internal standard. Using Br- internal standard for NO3- and NO2- ions and K+ for NH4+, peak area RSD values decrease significantly. The proposed system was applied to the speciation of inorganic nitrogen ions in rainwater samples. The recovery tests established for external calibration and standard addition techniques using one or two internal standards were within the range 100 +/- 10%. The CE results agree with those obtained by spectrophotometric methods.     

Determination of trace perchlorate in high-salinity water samples by ion chromatography with on-line preconcentration and preelution

A simple, automated system for the determination of trace perchlorate by ion chromatography (IC) with an online preconcentration technique is reported. The sample is preconcentrated, and less strongly held ions preeluted before the analyte is transferred to the principal separation system. This approach provides low limits of detection (LOD) and is particularly robust toward the effect of high concentrations of common anions, such as those present in groundwater samples. It compares favorably with currently promulgated EPA method 314.0. The LOD (S/N = 3) is 0.77 microg/L for a 2-mL reagent water sample and decreases more-or-less proportionately with increasing sample volume, at least up to 20 mL. Even with a sample of conductivity 14.7 mS/cm (approximately that of 0.1 M Na2SO4), the recovery of added perchlorate at the 25.0 microg/L level was still 92%. The concentration of added perchlorate in the range of 1-400 microg/L was linearly correlated to the peak area, with an r2 value of 0.9997. The recovery of perchlorate from artificial samples with different conductivity by the present method compares favorably with those from the currently recommended EPA Method. The ability of this approach to remove matrix interferences suggests that it would be also promising for perchlorate analysis in other challenging samples.     

强疏水性AS-15色谱柱测定茶叶中F-、Cl-、NO3-、PO4（3-）、SO4（2-）、BrO3-、Br-、NO2-的研究

建立了一种利用强疏水性分离柱,通过KOH梯度淋洗,同时测定茶叶中F-、Cl-、NO3-、PO43-、SO42-、BrO3-、Br-、NO2-的方法。采用沸水冲泡茶样,茶水比为1：50,时间为5 min,过滤后稳定30 min待测;样液经过活性炭净化,再用0.20μm滤膜过滤后待测。结果表明：8种无机阴离子色谱峰能达到完全的基线分离,且浓度与峰面积呈良好的线性关系,检出限均低于0.056mg/L,加标回收率为96.5%~105.1%,该法用于茶样中8种无机阴离子含量的测定,结果稳定且重复性较好。