PICO-TAG方法测定氨基酸的研究

详细讨论了用异硫氰酸苯酯（ＰＩＴＣ）柱前衍生,反相色谱法测定氨基酸（即ＰＩＣＯ－ＴＡＧ法）的最佳条件。研究了流动相配制时溶液ｐＨ值、乙腈含量等对色谱分析的影响,并且对色谱柱的退化与再生进行了说明。氨基酸含量在１．２５～１５００ｐｍｏｌ范围内线性良好,相关系数大于０．９９９,且大多数氨基酸保留时间的变异系数小于０．５％。氨基酸采用峰面积定量,测定变异系数为０．１～１．５％。     

气相色谱法测定人白蛋白制品中辛酸钠含量

本文报导用气相色谱法测定人白蛋白制品中辛酸钠含量。样品用正庚酸作内标,经酸化、氯仿抽提、浓缩后,通过ＨＰ－ＩＮＮＯＷａｘ柱,以氢火焰检测器测定。本法色谱峰形好,平均回收率及变异系数分别为９８．５４％、１．３９％。测定线性范围在１０７μｇ／０．２５ｍｌ～７２０μｇ／０．２５ｍｌ。最小检测限为７．４１０μｇ。实验操作简便,样品及溶剂用量少,可作为人白蛋白制品中辛酸钠含量的检测方法。     

双丙磷测定方法的改进

本文探讨了用氨基酸自动分析仪测定生物除草剂双丙磷的方法。结果表明,本方法能有效克服干扰,回收率为９７～１０２％。变异系数０．６９～１．０％,线性相关系数为０．９９９８。     

气相色谱法测定生物制品中苯酚含量

本文采用气相色谱法测定了几种生物制品中苯酚含量。样品无需进一步处理,加入内标液后直接上柱测定,色谱峰形良好,线性范围宽,平均回收率和变异系数分别为１０１．８％ 和１．０８５％ ,最小检测限为１０ μｇ／ｍ ｌ,本法操作简单,样品用量少,可作为测定生物制品中苯酚含量的一种常规方法。     

生物素—链霉亲和毒免疫学法测定地高辛的研究

采用国产链霉亲和素直接包被塑料板孔,生物素标记抗体,建立的竞争酶联免疫吸附试验的方法测定血中地高辛浓度,其测定灵敏度为０．９６４μｇ／Ｌ最低检测限为０．２２５１μｇ／Ｌ,测定三份低,中、高浓度的血甭标本,批内变异系数为８．９％、５．９％、２．４％;批间变民系数为１５．８％、１０．１％、９．２％,测定回收率在８９．１－１０７．２２％之间,此法与ＦＰＩＡ方法相关良好。     

离子对反相HPLC测定小鼠骨髓BFU—E,CFU—E中PRPP合成酶活性

采用离子对反相高效液相色谱法（ＩＰｒＨＰＬＣ）的单液等度洗脱,测定了小鼠骨髓红系爆增性集落形成单位（ＢＦＵ－Ｅｓ）与红系集落形成单位（ＣＦＵ－Ｅｓ）的ＰＲＰＰ合成酶活性。方法学研究表明,加入离子对试剂硫酸氢四丁基铵（ＴＢＡＨＳ）后,ＡＤＰ谱峰分离完全,其反应增加量易于计算。本法的批内变异系数平均值为－２．３０％￣－１．０６％与１．０６％￣２．３０％,平均相对偏差为０．８１％￣１．７４％,回收率为９     

外源乙醇胺对小麦幼苗某些抗逆生理指标的影响(简报)

在干旱胁迫条件下,经０．１％～１．０％乙醇胺处理的小麦幼苗叶片中,叶绿素含量和水势均增加,细胞的相对电导率降低,体内游离脯氨酸含量上升,幼苗株高和地上部鲜重增加。     

用傅里叶变换近红外光谱法测定完整油菜籽三种品质性状的初步研究

本文研究了用傅里叶变换近红外漫反射光谱法非破坏性测定完整油菜籽中油份、蛋白质和硫甙含量的方法。结果表明１：分析光束直径对测量有明显的影响;直径越大,效果越好;２：该方法对蛋白质和硫甙含量测定效果较好,相关系数分别为０．９４和０．９５,相对误差分别为２．１％和１６．２％,有望应用于品质育种等生产实践中。     

高效液相色谱测定血清中的非胆固醇甾醇

本文介绍一种用高效波相色谱（ＨＰＬＣ）同时测定血清中２４－脱氢胆固醇、７－烯胆甾烷醇、菜油甾醇、胆甾烷醇和β－谷甾醇的方法。血清加内标（６－氯豆甾醇）后用氢氧化钾醇溶液皂化,用正己烷提取其中的各种甾醇,将提出的甾醇衍生为苯氨基甲酸酯,用ＨＰＬＣ分离测定。本法样品处理简单,色谱分析时间短,批内和批间变异系数分别为２．２～３．８％和３．３～６．７％。本文也首次报告我国成年人血清非胆固醇甾醇水平,５种甾醇血清浓度的总和平均为１．５４ｍｇ／ｄｌ,是胆固醇的０．８６％。     

无花果曲霉原生质体形成与再生条件的探讨

根据正交试验得出无花果曲霉原生质体形成的最佳条件,用１％的混合酶液（０．５％纤维素酶＋０．２５％蜗牛酶＋０．２５％溶菌酶）作用无花果曲霉菌体细胞,原生质体产量达３．２×１０７个·ｍｌ－１,渗透压稳定剂为０．６ｍｏｌ·Ｌ－１ＫＣｌ于０．２ｍｏｌ·Ｌ－１ＰＯ３＋４（ｐＨ５．８）中,酶解时间和酶解温度分别为３．０ｈ、３０℃．比较不同酶解时间、再生稳定剂和碳源等因素对原生质体再生的影响,可确定最佳再生条件,再生率达３０％以上．     

Effects of aldosterone on the urinary excretion of total and non-dialyzable hydroxyproline

In order to explore the role of mineralocorticoids on collagen metabolism, the effects of aldosterone on the urinary excretion of total and non dialyzable hydroxyproline (HYPRO) was studied in rats. The administration of aldosterone in sesame oil, 75 microgram/100 g body weight to adrenalectomized rats maintained on 1% NaCl solution as drinking fluid and 1 mg of cortisone subcutaneously daily, provoked elevation of total and non dialyzable HYPRO in urine (P less than 0.001), when compared to similarly treated adrenalectomized rats receiving sesame oil but no aldosterone. Both groups showed a normal growth curve and had similar urinary excretion of creatinine. The effects of aldosterone are opposed to the known lowering effects of glucocorticoids on HYPRO excretion and may suggest an effect of aldosterone on collagen turnover. Alternatively, aldosterone may modify the metabolism or excretion of HYPRO in an opposite manner to that of glucocorticoids.     

The gravimetric method for the determination of residual moisture in freeze-dried biological products

The gravimetric test for the determination of residual moisture in freeze-dried biological products performed in a humidity- and temperature-controlled room with the use of scrupulous gravimetric analytical technique can be used to accurately determine residual moisture in freeze-dried biological products such as antihemophilic factor (human) or honey bee venom allergenic extract. This method determines the first water of hydration of sodium tartrate dihydrate (7.93%) to within 1.3% of the calculated value with a relative standard deviation of 0.3% for 10 replicates. For this gravimetric procedure, freeze-dried samples containing from 1.12 to 4.4% residual moisture had relative standard deviations ranging from 3.6 to 9.1%. Samples containing less than 1.0% residual moisture by the gravimetric method such as intravenous immune globulin and antihemophilic factor (human) had relative standard deviations ranging from 16.7 to 47.0%. Relative standard deviations for residual moisture tests performed on comparable samples by the Karl Fischer and thermogravimetric methods showed similar variability.     

Determination of isometamidium residues in animal-derived foods by liquid chromatography-tandem mass spectrometry

In this paper, a new determination method for isometamidium residues in animal-derived foods was developed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Isometamidium residues in bovine tissues and milk were extracted with the mixed solution of acetonitrile and 0.25 mol/L of ammonium formate-methanol (v/v, 1:1), concentrated and degreased, and determined by LC-MS/MS with quantification by external standard method. The results showed that the peak area of chromatogram was linearly related to the concentration of isometamidium in the range of 1-100 μg/L, and the limits of detection (LOD) and quantification (LOQ) were 0.05 μg/kg and 5 μg/kg, respectively. The average recoveries of spiked samples were in the range of 73.8-93.9% with relative standard deviations ranged from 2.3% to 7.5%. This method is simple, accurate and suitable for the identification and quantification for isometamidium in animal-derived foods.     

HPLC analysis of asymmetric dimethylarginine,symmetric dimethylarginine,homoarginine and arginine in small plasma volumes using a Gemini-NX column at high pH

There is increasing recognition of the clinical importance of endogenous nitric oxide synthase inhibitors in critical illness. This has highlighted the need for an accurate high performance liquid chromatography (HPLC) method for detection of asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA) in small volumes of blood. Here, the validation of an accurate, precise HPLC method for the determination of ADMA, SDMA, homoarginine and arginine concentrations in plasma is described. Solid phase extraction is followed by derivatisation with AccQ-Fluor™ and reversed phase separation on a Gemini-NX column at pH 9. Simultaneous detection by both UV–vis and fluorescence detectors affords extra validation. This solid phase extraction method gives absolute recoveries of more than 85% for ADMA and SDMA and relative recoveries of 102% for ADMA and 101% for SDMA. The intra-assay relative standard deviations are 2.1% and 2.3% for ADMA and SDMA, respectively, with inter-assay relative standard deviations of 2.7% and 3.1%, respectively. Advantages of this method include improved recovery of all analytes using isopropanol in the solid phase extraction; sharp, well-resolved chromatographic peaks using a high pH mobile phase; a non-endogenous internal standard, n-propyl l-arginine; and accurate and precise determination of methylated arginine concentrations from only 100 μL of plasma.     

Capillary electrophoresis–electrospray ionization-mass spectrometry using fused-silica capillaries to profile anionic metabolites

A capillary electrophoresis–electrospray ionization-mass spectrometry (CE–ESI-MS) method is proposed to profile anionic metabolites. This application is based on the use of a bare fused-silica capillary in two different characteristic modes, high-speed and high-resolution. The high-speed mode aims to simultaneously analyze a number of major anionic metabolites including organic acids, sugar phosphates, nucleotides and coenzymes. Using ammonium formate (pH 8.0) as the electrolyte and applying pressure-assisted flow, a standard mixture including 38 compounds can be analyzed in this way in less than 16 min. The relative standard deviations were better than 0.7 for the migration times and between 1.2 and 7.0 for the peak areas. However, the peaks of several isomers overlapped. Thus, a high-resolution mode was developed for these isomers. In this mode, a mixture of ammonium acetate (pH 10.0) and methanol as electrolyte allowed such isomers to be separately analyzed. The relative standard deviations were better than 0.9 for migration times and between 1.5 and 6.3 for peak areas. This was particularly advantageous for hexose phosphate isomers, which are difficult to separate using existing CE–MS methods. To evaluate the effectiveness of our proposed method, we performed metabolite profiling of extracts from moss. In the high-speed mode, all target metabolites except isocitrate could be determined. In the high-resolution mode, five successive peaks were obtained corresponding to the hexose phosphate isomers mannose 6-phosphate, glucose 6-phosphate, fructose 6-phosphate, glucose 1-phosphate and an unknown compound. These results indicate that our new method has great utility in the profiling of anionic metabolites.     

Isolation,identification and quantitation of urinary organic acids

An application of the HISLIB program for the comparison of gas chromatographic—mass spectrometric profiles of urinary organic acids isolated by extraction and ion-exchange methods is described. Ion-exchange methods are clearly superior to solvent extraction in terms of the variety of compounds isolated. However, the former method has practical difficulties which make solvent extraction more attractive for rapid analyses. For the compounds isolated by both methods, the precision of analysis is similar, with standard deviations of relative concentration in the range 10–30% for most compounds.     

高效液相色谱法测定山楂叶中熊果酸含量的研究

本文建立了一种可靠性高、重现性好的高效液相色谱(HPLC)测定山楂叶中熊果酸含量的方法,在测定中采用富集和固相萃取组合纯化工艺去除干扰物质。高效液相色谱测定条件为Hypersil(ODS)色谱柱,流动相为甲醇:0.2%磷酸二氢钠(90∶10,V/V),检测波长210nm,流速0.8mL/min。熊果酸浓度在100~800μg/mL与峰面积存在良好线性关系(r2=0.9992),该方法准确可靠,日内稳定性标准偏差在0.6%~1.5%,日间稳定性标准偏差在0.7%~2.6%。为不同产地山楂叶中熊果酸含量建立有效的分析方法。     

Development of a novel capillary electrophoresis chemiluminescence system for amino acid analysis

In the present study, a novel peroxyoxalate CE–CL system was developed to achieve high signal stability and sensitivity based on a design of a new interface including a new mixing mode and a new grounding electrode mode. Amino acids fluorescently tagged with dansyl chloride and naphthalene‐2,3‐dicarboxaldehyde(NDA) were used for the study. Experiment results show this new system is quite effective to separate and detect amine acid with high stability and resolute. The detection limits were 1.1 nmol/L for dansyl‐leucine (Leu) and 2.0 nmol/L for dansyl‐aspartic acid (Asp). The relative standard deviations of peak height and migration time were in the ranges of 2.3–3.8% and 1.2–1.5%, respectively. Copyright © 2008 John Wiley & Sons, Ltd.     

Determination of O-benzylguanine in human plasma by reversed-phase high-performance liquid chromatography

A high-performance liquid chromatographic assay for O⁶-benzylguanine utilizing liquid-liquid extraction and reversed-phase chromatography has been developed. Plasma samples were alkalinized, extracted into ethyl acetate, evaporated, and the residues were constituted and chromatographed. Separation was accomplished by gradient elution with a mobile phase of methanol, acetonitrile, and phosphate buffer, pH 3.2. Eluted compounds were detected spectrophotometrically at 280 nm. Sample quantitation was obtained from the regression line of six-point standard curves ranging from 25 to 400 ng/ml. O⁶-Benzylguanine peak heights were compared to peak heights of O⁶-(p-chlorobenzyl)guanine (internal standard). The average regression coefficient was 0.999 (n = 4). High concentration (305 ng/ml) and low concentration (38 ng/ml) quality control samples were determined with a day-to-day relative standard deviation of 7 and 8%, respectively (n = 18). The within-day relative standard deviations were 2.7 and 3.0% (n = 18) for the high and low concentration quality control specimens, respectively. Sample quantitation was reliable to 25 ng/ml with a signal-to-noise ratio of 8:1. This method was applied to plasma samples obtained from patients in a clinical trial of O⁶-benzylguanine.     

A simple sensitive program for detecting internal repeats in sets of multiply aligned homologous proteins

We designed a simple but sensitive program, IntraCompare, for identifying internal repeats in families of homologous proteins. The protein sequences are aligned (Clustal X), the regions to be compared are selected, and all potential repeat sequences are compared with all others. The output provides comparison scores (GAP program) expressed in standard deviations.