Determination of serum creatinine by isotope dilution method using discharge-assisted thermospray liquid chromatography/mass spectrometry

A discharge-assisted thermospray (plasmaspray) liquid chromatography/mass spectrometric method for the determination of serum creatinine is described. The method incorporates stable isotope dilution using (D3)creatinine as an internal standard. Separation is performed in reversed-phase high-performance liquid chromatography using 0.01 M aqueous ammonium acetate as a flow solvent. Effluents are directly introduced to the mass spectrometer and [MH]+ ions are monitored during LC/MS using the selected ion monitoring method. Satisfactory agreement between the analytical result and the certified value of the serum sample of standard reference material and relative standard deviation ranging from 0.6% to 1.2% was obtained.     

Rat fetal ventral mesencephalon grown as solid tissue cultures: influence of culture time and BDNF treatment on dopamine neuron survival and function

The method of analysis described permits the determination of 2,4-dinitrobenzoic acid down to the lower microg l(-1) range in the urine of persons exposed to dinitrotoluene. 2,4-Dinitrobenzoic acid is the main metabolite of 2,4-dinitrotoluene and technical dinitrotoluene. After acidic hydrolysis, which served to release the conjugated part of the 2,4-dinitrobenzoic acid, the analyte was selectively separated from the urine matrix via various extraction steps and then derivatised to the methyl ester. Quantitative analysis was carried out using capillary gas chromatography and mass selective detection. 3,5-Dinitrobenzoic acid was used as an internal standard. The detection limit was 1 microg l(-1) urine. The relative standard deviations of within-series imprecision were between 5 and 6%. The relative recoveries were between 91 and 110% depending on the concentration. The analytical method developed as part of this study was used to investigate a collective consisting of 82 urine samples from persons working in the area of explosives disposal. The concentrations of 2,4-dinitrobenzoic acid determined ranged from the detection limit to 95 microg l(-1) urine. The method allowed the quantification of low-level internal exposure to dinitrotoluene.     

固相微萃取一气相色谱/质谱法测定焦化废水中有机物的研究

采用固相微萃取(SPME)技术结合气相色谱/质谱(GC/MS)法对焦化废水中的有机物进行了检测和分析。考虑废水中主要的有机物,对影响SPME的参数进行了优化。该方法在所测的范围内具有良好的线性(相关系数0.99),重复测定的相对标准偏差小于15%,回收率为87.9%～128.1%,定量下限为5μg/L。采用该方法对某焦化厂废水样品中存在的15种具有代表性的有机物进行分析,结果表明,采用SPME预处理方式可比常规方法节省1 h,是一种快速、准确、简便、高效的分析方法。     

Normal-phase liquid chromatography of plant hormones using reversed cholic acid micelles as the mobile phase

When several plant hormones with similar structures are present in a sample, conventional analytical methods are not sufficiently selective to effectively differentiate them. However, the excellent selectivity of micellar liquid chromatography allows similarly structured compounds to be easily differentiated. We used reversed cholic acid micelles dissolved in tetrahydrofuran as the mobile phase in normal-phase chromatography of seven plant hormones. Our results conformed closely to those predicted by the pseudophase micellar liquid chromatography theory. The chromatographic efficiencies were calculated from the peak width and the retention times, and we compared these values with those obtained by reversed-phase chromatography using sodium dodecyl sulfate mobile phase in water. To test the efficiency of this selective method for the analysis of plant tissues that may also contain contaminants, we applied it to homogeneous suspensions of spiked maize roots. Recoveries ranged from 91 to 110%, the relative standard deviations were between 0.46 and 10.03%, and the detection limits were between 0.08 and 0.80 micrograms g-1.     

以电子废料为原料的冶炼烟尘中氯的测定

氯元素是含有有机脂“城市矿山”原料冶炼烟尘中主要的卤素元素。氯离子的准确测定可以给回收冶炼烟尘中有价金属熔炼配料、预防烟气管道腐蚀提供参考依据。研究建立了硝酸溶样—离子色谱法测定冶炼烟尘中氯含量的分析方法,通过优化试验条件,进行了精密度和准确度试验,氯的相对标准偏差(RSD,n=7)为0.56%~2.29%,氯的加标回收率为97.5%~104.0%。该方法操作简单,快速高效,准确度较高,能满足冶炼烟尘中氯含量的分析需要。     

Identification of dextrans using rapid fluid chromatography

It is reported about an analytical method for routine control of clinical dextrans, a method which is considerably quicker than the previously used ones. It is based on the application of HPLC (high pressure liquid chromatography) to permeation chromatography of dextrans on controlled pore glass beads (CPG). The time required for a permeation chromatogram of a dextran sample could be reduced to less than one hour. Calibration curves, necessary for the evaluation of the chromatograms, were established by use of Pharmacia-Testdextrans.     

Use of capillary electrophoresis methods to characterize the pharmacokinetics of antisense drugs

As antisense drugs become mature for clinical trials, analytical techniques to analyze antisense DNA in biological media for characterization of their pharmacokinetics will be in demand. Due to the superior resolving power of capillary gel electrophoresis (CGE), CGE will likely be a preferred method in quantifying intact oligonucleotides as well as the putative metabolic products. Nonetheless, biological mediums can influence the stability of the gel column, making a CGE assay time-consuming. In one approach, high-performance liquid chromatography (HPLC) was used to quantify the total amount of antisense compounds to increase the sample throughput and CGE was used to determine the relative percentage of the intact and metabolic species on specific samples. Alternatively, extensive sample pretreatment procedures were performed and the samples were quantified and characterized directly by CGE alone with the use of an internal standard. Both methods have been used to characterize the pharmacokinetics of antisense compounds. This review focuses on the instrumental and technical aspects of analyzing antisense DNA in biological mediums using CGE either as a single or a combined method towards better understanding of the pharmacokinetics of antisense DNA. Moreover, the newer analytical technologies of capillary electrophoresis (CE), which hold great potential to be used for pharmacokinetic applications, such as the replenishable sieving matrix combined with an innovative coupling approach and microchip CE, will also be explored.     

Is sulbactam really the answer for treatment of infections caused by multiresistant strains of Acinetobacter spp.?

An analytical method for a rapid reverse-phase liquid chromatography of amino acids is presented. The total analysis time was 19 min. The average relative deviation over the measured peak area was lower than 10% and the fluorescent response was linear with concentration for OPA derivatives (r > 0.99) in the range 100-1000 nM. The proposed method was applied to the determination of free amino acids in two microalgae species (Chlorella pyrenoidosa and Chlamydomonas rinhardtii). The principal aminoacids found were alanine, arginine leucine, serine and glutamic acid.     

Gas-liquid chromatographic determination of chloramphenicol in agricultural crops

A method is presented for the gas-liquid chromatographic determination of chloramphenicol in agricultural crops. Chloramphenicol is extracted with ethyl acetate, cleaned up by silicic acid column chromatography, acetylated with acetic anhydride and pyridine, and then measured by gas-liquid chromatography with electron capture detection. Two stationary phases, DEGS + phosphoric acid and Reoplex 400, were used. The sensitivity was ca 8 ng (40% full scale deflection). The efficicency of the analytical method was evaluated by analyzing crops fortified with chloramphenicol. The average recovery ranged from 72% in unpolished rice to 86% in Chinese radishes.     

顶空固相微萃取-气相色谱质谱联用测定废钢回收冶炼厂空气中多氯联苯

报道了顶空固相微萃取-气相色谱质谱联用测定废钢回收冶炼厂空气中多氯联苯的分析方法。综合考察了顶空体积、离子强度、温度以及萃取时间对方法回收率的影响,得到了固相微萃取技术应用于分析多氯联苯的最佳实验参数,并就方法的有效性进行研究。方法用于测定废钢回收冶炼厂周围空气中多氯联苯,表观回收率为82.5%~109.0%,相对标准偏差小于17.0%,检测限为0.08~0.38 ng/L。结果表明,该方法具有准确、快速、灵敏度高、简便等特点。     

离子选择电极法盐酸雾自动监测系统的实现

基于化学湿法采样、分析原理,自主设计集成了一套酸再生离子选择电极法盐酸雾排放连续自动监测系统,并在某钢厂冷轧酸再生机组安装调试应用,实现了盐酸雾排放的湿法自动监测。系统投入运行后,维护工作量小,运行稳定。同步参照国家HJ/T 75—2007标准的自动监测参比方法比对技术要求,用离子色谱法和硫氰酸汞分光光度法两种国家标准方法开展参比方法比对,比对监测结果显示相对误差分别为-3.2%和-7.8%,验证了自动监测数据的准确性。另外,结合炉温、废酸流量、空燃比等数据,建立数学模型,给出最佳操作条件,实现了排放超标预警和优化控制。     

高频炉燃烧红外吸收法测定钛精矿中硫

对于钛精矿中硫的测定,现有标准方法为燃烧-碘量法,该方法的分析流程较长,不适合大批量样品的分析;同时方法的测定范围有限,仅适合硫质量分数在0.025%～0.500%的样品。为适应现有钛精矿的生产和科研需要,实验建立了高频炉燃烧红外吸收法测定钛精矿中硫的分析方法。对样品量、燃烧用助熔剂种类及用量等测试条件进行了优选。确定的最佳分析条件为:称取0.40g样品于坩埚中,加入0.5g锡粒、0.3g纯铁屑、1.3g钨粒助熔剂进行测定。采用钛精矿标准样品分段绘制硫的校准曲线,硫质量分数的测定范围为0.004 8%～2.76%;方法定量限为0.000 6%,完全满足现有钛精矿的测定需求。对硫质量分数在0.009 2%～1.51%的钛精矿样品进行了测定,测定值的相对标准偏差(n=8)为0.33%～1.8%。实验方法的测定结果与硫酸钡重量法吻合,对低硫样品的加标回收率为90%～105%。     

Effects of piracetam on the performance of rats in a delayed match-to-position task

The growing use of antibody-based separation methods has paralleled the expansion of immunochemical detection methods in moving beyond the clinical diagnostic field to applications in environmental monitoring. In recent years high-performance immunoaffinity chromatography, which began as a separation technique in biochemical and clinical research, has been adapted for separating and quantifying environmental pollutants. Bioaffinity offers a selective biological basis for separation that can be incorporated into a modular analytical process for more efficient environmental analysis. The use of immunoaffinity chromatography for separation complements the use of immunoassay for detection. A widely used immunochemical detection method for environmental analyses is enzyme immunoassay. The objective of this paper is to review the status of bioaffinity-based analytical procedures for environmental applications and human exposure assessment studies. Environmental methods based on bioaffinity range from mature immunoassays to emerging techniques such as immunosensors and immunoaffinity chromatography procedures for small molecules.     

惰气熔融-热导法测定金属纤维铁铬铝中的氮含量

本文针对金属纤维铁铬铝(FeCrAl)中的氮含量进行研究,建立了惰气熔融-热导法测定金属纤维FeCrAl中氮含量的新方法。研究了不同助熔剂、称样量、分析时间及比较器水平对实验结果的影响。确定采用镍做助熔剂,称样量为0.1 g,分析时间为55 s,比较器水平为1的条件对金属纤维FeCrAl中的氮含量进行测定。本方法测定的氮含量相对标准偏差为4.6%,所得数据重复性好、结果可靠;该方法操作简单、分析速度快。     

X射线荧光光谱法测定锌合金中铜和铁

通过用未校正UniQuant软件对样品进行定性分析,找出样品中可能含有的元素,并对其逐一进行分析线扫描,确定样品中元素种类及大概含量,然后在最佳的仪器分析条件下,采用单点校正曲线,对锌合金中铜、铁元素进行了测试,从而实现X射线荧光光谱法(XRF)对锌合金中铜和铁的检测。考察了分析时间、探测器、分析线及制样方法对分析结果的影响。结果表明:分析时间为60 s,选择FPC探测器,以Kα线作为分析线时,待测元素的灵敏度和精密度较高。对铣成的块状锌合金样品、屑状样品的粉末与硼酸通过压制成片状样品进行直接分析,测定结果与电解法和ICP-AES法基本一致,相对标准偏差分别为0.29%和1.9%(n=6),极差分别为0.016%和0.000 8%,小于现有国家标准方法中规定的重复性限。     

惰气熔融-红外吸收法测定钛钼合金中氧

对惰气熔融-红外吸收法测定钛钼合金中氧含量的分析方法进行了研究。确定了最佳分析条件为:称取0.06 g样品于0.85 g镍篮中,投入石墨坩埚中进行测定,控制分析功率为5.0 kW,分析时间为40 s。使用钛标样501-657建立校准曲线,得到回归方程为y=1.336 88 x。利用3倍空白标准偏差计算得到氧的检出限为0.000 22%。采用方法测定了2个钛钼合金样品中氧的含量,测定结果的相对标准偏差(RSD,n=11)分别为2.0%和3.3%。方法加标回收率在95%~103%之间。     

Rapid analytical tryptic mapping of a recombinant chimeric monoclonal antibody and method validation challenges

A rapid and reproducible analytical tryptic mapping method was developed as an identity test for a recombinant chimeric monoclonal antibody for lot release testing. The unfolding, reduction, carboxymethylation, trypsin digestion, and reversed-phase (RP) HPLC steps were optimized to provide a reproducible method. The optimized method requires 30 min for unfolding the protein, 30 min for carboxymethylation, 4 h for digestion with TPCK-trypsin and 140 min for RPHPLC analysis. The total time required is less than 8 h compared to conventional procedures, which must be performed over several days. The optimized method was validated for its precision, recovery, specificity, and robustness. The precision of the method was determined by repeatability and intermediate precision experiments. Relative standard deviation (RSD) values were < or = 10% for the relative peak areas of marker peaks. The mean recovery of these marker peaks was 88.4%. The specificity was demonstrated by the unique tryptic mapping patterns obtained compared with several other monoclonal antibodies. Robustness was demonstrated by the relative insensitivity of the tryptic map to small deliberate changes in key method parameters. Excessive relative peak area variability observed for one peak (RSD 52%) was traced to adsorption to glass autosampler vials. This variability was substantially reduced (RSD 11%) by substituting polypropylene autosampler vials. The data demonstrate that this method may be applicable to a wide range of pharmaceutically relevant monoclonal antibodies.     

铅试金重量法结合数学校正法测定银

铅试金重量法古老而经典,其结果代表性强、准确度高、稳定性好,是贵金属最常用、最有效的分离及分析方法之一。但仍存在分析流程长,分析结果系统偏低(尤其是银)等缺点,若采用二次或三次试金(如国家或行业标准),则会使分析流程更长,操作成本更高。实验通过对铅试金分析中造渣富集和除铅精炼等试金分析基本原理的探索和分析,在控制好熔炼和灰吹条件的前提下,根据一次试金的合粒含银量及铅扣质量,从理论上建立了对熔炼和灰吹过程中银损失量进行校正的数学模型,进而提出了铅试金重量法结合数学校正法测定银的方法,完全省去了二次试金的步骤。选取粗铜、铜精矿和铜阳极泥等3种代表性样品,一方面采用铅试金重量法结合数学校正法对银进行测定,另一方面通过对熔渣和灰皿中损失的银进行二次试金试验,得到银的回收补正值(该法简称为铅试金-回收补正法),结果表明,实验方法测定值与回收补正值的相对差值均在±0.5％以内。采用实验方法对粗铜中银进行11次平行测定,结果的相对标准偏差(RSD)为0.9%。此外,实验方法采用高等数学求导的手段,求出了在不同试样及配料方案下的最佳铅扣质量,并对相关分析标准所规定的铅扣质量作了比较合理和科学的评述。     

高效液相色谱法测定湿法冶金LIX984N铜萃取剂中醛肟和酮肟

醛肟和酮肟的含量直接决定其羟肟类铜萃取剂(以下简称铜萃取剂)的萃取性能状况,因此建立简便可行的测定铜萃取剂中醛肟和酮肟含量的方法意义重大。实验在无醛肟和酮肟标准样品的前提下,选取LIX984N为原料,采用液相色谱仪以半制备方法制备了纯醛肟和酮肟,并以此为标准品,建立了测定湿法冶金LIX984N铜萃取剂产品中醛肟和酮肟的高效液相色谱(HPLC)分析方法。优化后的液相色谱仪操作条件如下:Chromatorex(迪玛)C18(300 mm×30 mm×10 μm)反相柱为半制备柱,ChromatorexC18(250 mm×4.6 mm×5 μm)反相柱为分析柱,甲醇为流动相,流动相流速为1.0 mL/min,柱温为室温,紫外检测器波长为254 nm。实验表明,醛肟和酮肟均在质量浓度为0.4 μg/mL～1.50 mg/mL范围内与其对应的色谱峰面积呈良好的线性关系,相关系数均大于0.998。醛肟和酮肟的方法检出限分别为0.12和0.15 μg/mL,测定下限分别为0.4和0.5 μg/mL。按照实验方法对LIX984N铜萃取剂样品中醛肟和酮肟进行测定,结果的相对标准偏差(RSD,n=5)均小于0.5%,加标回收率为94%～129%。     

Liquid chromatographic determination of ivermectin in feed

An analytical method for determining ivermectin in feed at 0.50-3 ppm is presented. The method is based on liquid chromatographic measurement after sample preparation by adsorption chromatography on alumina and solid-phase extraction. Two complete, final, finished medicated feeds and the corresponding control feeds used in their preparation were analyzed. Recoveries from feeds fortified at 50-150% of the 2 ppm ivermectin use concentration also were determined. Mean recoveries from replicate analyses ranged from 90 to 100%, and coefficients of variation (CVs) were less than 4.5%. No significant interferences were found in control feeds. The pooled distribution of individual analytical results (n = 100) gave a mean recovery of 100%, a recovery range of 90-111%, and an overall CV of 5.5%. Resolution of the total variance into its 2 components gave a within-laboratory CV of 4.1% and a between-laboratory CV of 3.4%. There was no significant difference in recoveries among laboratories, days, concentrations, and feed base or between fortified and medicated feeds (P > 0.2).