Analysis of the disaccharides derived from hyaluronic acid and chondroitin sulfate by capillary electrophoresis with sample stacking

CE conditions for monitoring the unsaturated disaccharides of hyaluronic acid (di-HA) and chondroitin sulfate (di-CS) using an alkaline tetraborate buffer, electrokinetic sample injection, and UV absorption detection at 232 nm are reported. Separations were performed in an uncoated fused-silica capillary having reversed polarity and reversed electroosmosis generated with the addition of CTAB to the buffer. The influence of various separation parameters, including the concentration of CTAB, buffer pH, concentration of tetraborate, and applied voltage, on the resolution of the two disaccharides was investigated. Baseline separation was obtained with 25 mM tetraborate at pH 10.0 and having 0.05 mM CTAB. Chloride and phosphate in the sample are beneficial for the stacking of the disaccharides, with di-HA forming a much sharper peak than di-CS. Using samples prepared in 25 mM Tris-HCl (pH 7.5) and electrokinetic injection at the cathode at -10 kV for 40 s, linear relationships between the corrected peak area and the concentration of the disaccharides have been found in the ranges of 1.0-400.0 and 0.1-1.0 microg/mL (0.2-1.0 microg/mL for di-CS), with correlation coefficients being >0.9933 in all cases. The RSDs of detection times and corrected peak areas were between 1.13-1.24 and 1.57-2.13%, respectively. Applied to human serum samples that were prepared by ethanol precipitation and depolymerization of the two polysaccharides with chondroitinase ABC reveals comigration of endogenous compounds with di-HA and a sample-dependent detection time. The di-HA content in the serum sample can be estimated via subtraction of the blank peak that is obtained without enzymatic hydrolysis.     

Rapid and sensitive liquid chromatography-tandem mass spectrometry for the quantitation of epirubicin and identification of metabolites in biological samples

A highly sensitive and selective liquid chromatography-mass spectrometry (LC-MS) method has been developed for the determination of epirubicin in serum and cell specimens using daunorubicin as an internal standard. Using atmospheric pressure chemical ionisation (APCI), the epirubicin metabolites were readily distinguishable by their fragmentation pattern in the mass spectrometer. Selected reaction monitoring (SRM) mode was employed for quantitation of epirubicin and the metabolites. Following extraction, chromatography was performed on a C18 column with a mobile phase consisting of water-acetonitrile-formic acid, pH 3.2, with a flow rate of 200 μl/min. The limit of detection (LOD) and the limit of quantitation (LOQ) of this method in serum were determined to be 1.0 and 2.5 ng/ml, respectively. Linearity of the method was verified over the concentration range of 2.5-2000 ng/ml, with a high correlation coefficient (R² ≥ 0.998). For the extraction procedure, an aliquot of 500 μl serum, spiked with internal standard, was extracted using a chloroform-2-isopropanol (2:1, v/v) mixture. The method has been applied to the analysis of epirubicin in cancer cell samples and the identification of known and unknown metabolites in clinical trial patient serum samples.     

Electrochemical Evaluation of Nucleoside Analogue Lamivudine in Pharmaceutical Dosage Forms and Human Serum

Lamivudine (LAM) is a synthetic nucleoside analogue with activity against human immunodeficiency virus‐type 1 (HIV‐1) and Hepatitis B virus (HBV). The aim of this study was to determine LAM levels in serum and pharmaceutical formulations, by means of electrochemical methods using hanging mercury drop electrode (HMDE). On this electrode, LAM undergoes irreversible reduction at the peak potential near E_p?1.26 V (vs. Ag/AgCl/3 M KCl). Reduction LAM signals were measured by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and square‐wave voltammetry (OSW). DPV and OSW techniques for the determination of LAM in acetate buffer at pH 4.5, which allows quantitation over the 4×10^?6 to 1×10^?4 M range in supporting electrolyte for both methods, were proposed. The linear response was obtained in acetate buffer in the ranges of 2×10^?6 to 2×10^?4 M for spiked serum samples at pH 4.5 for both techniques. The repeatability and reproducibility of the methods for all media were determined. The standard addition method was used in serum. Precision and accuracy were also checked in all media. No electroactive interferences from the endogenous substances were found in serum. With respect to side effects of high doses and short half‐life of LAM, a fast and simple detection method is described in this study.     

亚临床肝性脑病患者的血清锌,铜含量的测定及临床意义

检测了３０例慢性活动性肝炎患者、３０例肝硬化患者、３０例亚临床肝性脑病患者血清中的铜、锌含量，并与正常对照组进行比较分析，探讨了微量元素铜、锌的血清含量改变及其影响因素，分析其临床意义。结果表明体内的铜锌含量与肝脏功能有密切的关系。在慢性活动性肝炎时，虽然肝脏功能有一定的损害，但由于肝脏的代偿能力强，铜，锌含量仍可保持在正常水平，而在肝硬化、亚临床肝性脑病时，铜锌明显降低，而铜锌含量的降低又导致机     

人血清与头发中铜,锌,铁,钙,镁,锰含量的相关分析

平行测定了５４例（男３１例，女２３例）成人血清和头发中铜，锌，铁，钙，镁和锰的含量，相关分析结果表明，血清与头发中６种元素的不相关两类样品比较，血清测定方法简便，误差小，但在检测人体内元素含量水平时，头发的测量结果比血清更灵敏。     

偶氮胂-DBS用于光度法测定牛血清白蛋白

在室温下,于pH 2.5的Britton-Robinson缓冲溶液中及非离子表面活性剂OP存在下,牛血清白蛋白(BSA)与偶氮胂-DBS的复合物的最大吸收在514 nm波长处,但显色复合物与试剂空白吸光度之差在370 nm处最大,选择在370 nm处测定,反应迅速完成。非离子表面活性剂OP可提高反应灵敏度及复合物稳定性。乙醇可提高体系灵敏度。BSA的质量范围在0~60.0 mg.L-1范围内符合比耳定律,方法表观摩尔吸光率3ε70 nm=8.58×105L.mol-1.cm-1。方法用于测定血清样品中蛋白质的总量,5次测定值的RSD为0.60%,回收率为98.0%。     

血清必需元素测定中样品预处理方法的探讨

对血清必需元素测定的样品预处理方法进行了研究，用火焰原子吸收法测定了经不同处理的血清样品中的锌，铜，铁，钙，镁含量，结果显示，预处理方法不同，其测定结果有较大差异，变异系数，镁为７．９４％，锌，铜，铁，钙在１５．１９％～５３．５３％之间，并对各样品作了精密度和准确度实验。     

甲亢病人血清镁含量及其临床意义

用火焰原子吸收法测定了２０００例甲亢病人的血清镁含量及１２００例天津市正常人群血清镁含量，结果显示，甲亢病人血清镁含量显著低于正常人群，有显著统计意义（Ｐ〈０．０１）。提示：甲亢病人血清镁含量对甲亢病诊断及治疗过程的镁的摄入补充有重要的意义。     

116例冠心病患者血清中钙镁钡铝锶含量的研究

测定１１６例冠心病患者血清中钙，镁，钡，铝和锶的含量并与正常值比较，常量元素钙，镁和微量元素锶降低，而微量元素钡和铝升高，它们之间的差异都有显著或高度显著性。Ｐ〈０．０５或Ｐ〈０．０１。     

Studies on Interactions of Antibiotics with Serum Albumin by Surface Plasmon Resonance Biosensor

Introduction Humanserumalbumin(HSA)isawell known transportproteinforavarietyofmoleculesandions[1].Thebindingofadrugtoserumalbuminhasimportant pharmacokineticconsequencesbecauseitinfluences distribution,excretionandpharmacologicaleffectsof thedruginthebody…