Multivariate Optimization and Validation of HPLC Method for Determination of Spiramycin I in Tablets

Chromatographia - Spiramycin (SPY) is an antibiotic belonging to the class of macrolides. Its main structurally related components are SPY I, SPY II and SPY III. The aim of this work was to...     

尿中磺酸化胆汁酸的流动注射固定化酶化学发光法

肝胆系统有疾患，会导致尿中磺酸化胆汁酸浓度的增加。根据尿中磺酸化胆汁酸的浓度可以判断肝脏机能是否正常。基于流动注射分析原理，利用化学发光法和固定化酶反应，建立了一个新的尿中磺酸化胆汁酸的临床快速分析法。进样量为20μL；分析速度30样/h；检出限为0.1μmol/L；RSD小于2.2%；线性范围在0.1-12μmol/L之内。     

酶法测定血清中胆汁酸

研究了用3－α羟基类固醇脱氢酶与黄递酶双酶体系催化的酶促胆汁酸测定方法。对影响酶促反应测定结果的主要因素进行了系统的研究，并在其基础上确定了测定试剂的组成为：黄递酶，175U／L；3－α羟基类固醇脱氢酶600U／L；烟酰胺腺嘌呤二核苷酸（NAD^ )0.88mmol/L；硝基四唑蓝（NTB）175mg/L；磷酸盐缓冲溶液（pH7.0),50mmol/L。用以上试剂对胆汁酸测定的线性范围为0－300μmol/L，RSD为3．3％，回收率为105．3％。     

增效荧光光谱法测定片剂药物中的甲睾酮

研究了甲睾酮与浓硫酸反应产物的荧光光谱性质，提出了利用表面活性剂增敏荧光光谱测量甲睾酮含量的新方法，初步探讨了表面活性剂十二烷基硫酸钠（SDS）的增敏作用机理，并证实溶液中溶解氧对本实验体系有明显的荧光猝灭作用。该法操作简便，检出限低，用于成品药物分析，结果令人满意。     

Multivariate Optimization in Preconcentration Procedure for Manganese Determination in Seawater Samples by FAAS

In the present paper, a preconcentration procedure for manganese determination in seawater samples by flame atomic absorption spectrometry (FAAS) is proposed. It is based on the solid phase extraction of manganese(II) ions as a 4-(2-pyridylazo-resorcinol) (PAR) chelate using activated carbon as sorbent. Optimization of the experimental parameters (pH, activated carbon mass, PAR mass and shaking time) was carried out using a two-level full factorial design (2⁴) and two Doehlert matrix designs. The results of the factorial design, considering the analysis of variance (ANOVA), demonstrate that all these factors and their interactions (pH × PAR mass; pH × activated carbon mass and activated carbon mass × shaking time) are statistically significant. Final optimization was carried out using Doehlert matrix designs considering the results of the factorial design. The validation process evaluated the following parameters: effect of other metal ions, calibration curve, precision, accuracy and robustness. The procedure allows manganese determination in seawater samples with limits of detection (3/S) and quantification (10/S) of 16ngL^–1 and 53ngL^–1 respectively, and a preconcentration factor of 152. The analysis of certified reference materials demonstrated that the proposed procedure can also be used for manganese determination in biological samples. The procedure is not affected by matrix interferences and could be satisfactorily applied in manganese determination in seawater samples. Manganese determination in surface seawater samples collected from the shore of Salvador city, Brazil, was performed, and concentrations ranging from 0.51 to 2.59µgL^–1 were found.     

钾盐矿床中含石膏盐样品测定的质量控制方法改进

由于现行标准中没有直接针对含石膏钾盐样品分析的方法,同时没有国家一级有证标准物质进行质量监控,因此在测定含石膏钾盐样品时较为困难。为提高含石膏盐样品分析结果的准确度、精密度,采用不同的溶矿温度、称样量、以及放置时间对含石膏钾盐样品溶解方法进行实验。得出在称样量为0.500 0g、水温80℃、放置时间为24h时,用电感耦合等离子体发射光谱法测定,通过样品中各组分百分数加和、溶液中元素阴阳离子平衡以及加标回收实验进行数据质量监控。实验结果满足《地质矿产实验室测试质量管理规范》对钾盐样品分析质量的要求。为钾盐勘查提供准确的数据支撑。     

Flow-Injection Determination of Benzylpenicillin Novocaine Salt in Penicillin Preparations with Spectrophotometric Detection

Working conditions were found for determining the novocaine salt of benzylpenicillin antibiotic as its 4,6-dinitrobenzofuroxan derivative by flow-injection analysis with spectrophotometric detection ( = 510 nm). The best results were obtained for flows of methanol (ethanol) and water with a volume ratio of 30 : 70. The calibration range of the pharmaceutical is 0.28–10 g/mL with a throughput capacity of 30 samples/h. The limit of detection (3, n= 4) is 0.14 g/mL. Amino acids and components of penicillin-containing pharmaceuticals did not interfere with the determination. Procedures for determining benzylpenicillin novocaine salt in medicinal formulations containing benzylpenicillin N,N"-dibenzylethylenediamine, potassium, and sodium salts and some other     

A New Trace Analytic Method for the Determination of Sequence-Specific DNA with Fluorescent Probes

A new method of fluorescence spectrometry detection of single-strand DNA (ssDNA) was established by hybridizing the ssDNA with its complementary ssDNA to form double-stranded DNA (dsDNA). Our results show that the fluorescence intensity increased significantly when the nucleic acid molecular “light switch"(Ru(phen)₂dppx²⁺) or Hoechst 33258 dye interacted with dsDNA, and the fluorescence intensity also increased as the DNA concentration increased. The changing law was also studied about how the fluorescence intensity changed when the two kinds of fluorescent probes interacted with oligonucleotide of different lengths and different sequences, as well as DNA-DNA′ hybridization products. Then, the effect of the bases mismatch, varying length of DNA chain, and different DNA sequences on the fluorescence intensity were explored at the same time, by detecting the specific DNA sequence of avian influenza H1N1 virus, cauliflower mosaic virus, and hepatitis C virus. Additionally, the selectivity, linear range, and sensitivity of the two probes were compared.     

核黄素荧光猝灭法测定2,4,6-三硝基苯酚

基于核黄素与2,4,6-三硝基苯酚混合后产生荧光猝灭现象,建立了核黄素作为荧光探针测定2,4,6-三硝基苯酚的新方法。 在0.2 mol/L磷酸盐(NaH₂PO₄-Na₂HPO₄)缓冲溶液(pH=6.2)中,响应时间为1 min时,检测2,4,6-三硝基苯酚的线性范围为2.5~1000 μmol/L,相关系数为0.9938,检测限为0.55 μmol/L。 当加入5.00和20.00 μmol/L 2,4,6-三硝基苯酚到水样后,回收率在98.2%~103.5%之间。 方法简便,选择性好,线性范围宽,可用于实际水样中2,4,6-三硝基苯酚的定性定量分析。     

电极法测定食盐氟

采用电极法测定了食盐中氟化物含量，空白值，重现性及回收率均符合微量分析要求。     

基于Hoechst33258荧光染料检测单链DNA的方法研究

根据Hoechst与ssDNA作用时不产生荧光或荧光很弱,而与dsDNA作用时荧光增强的原理,将待测ssDNA与互补ssDNA杂交形成dsDNA,实现Hoechst染料对ssDNA的检测.文中研究了不同序列、不同长度、互补链及碱基错配链等杂交产物与Hoechst染料作用的荧光强度的变化规律.同时以H1N1禽流感病毒DN...     

Computer Simulations of the Formation of Bile Salt Micelles and Bile Salt/DPPC Mixed Micelles in Aqueous Solutions

Brownian dynamics simulations for a coarse-grained model have been performed to study the formation of micelles from bile salts and mixed micelles with dipalmitoyl-phosphatidylcholine (DPPC) in aqueous solutions. The particular association behavior of bile salts as facial surfactants was shown to be caused by their special molecular architecture with a hydrophilic and a hydrophobic side. The experimentally observed smooth transition into the micellar region with increasing concentration is reproduced. Micelle size distributions have been evaluated at different bile salt concentrations. Typical structures of pure bile salt micelles could be identified. The composition and the structure of mixed micelles have been studied in their dependence on the bile salt/lipid concentration ratio in the aqueous solution. We have found that the bile salt fraction in the mixed micelles increases considerably with increasing bile salt/lipid concentration ratio and decreasing micelle size. The structural and thermodynamic features of micelle formation in the aqueous bile salt solutions with DPPC, which we have studied with the coarse-grained model, are in good qualitative agreement with experimental findings.     

Determination of Trialkyl and Triaryl Phosphates by Narrow-bore Liquid Chromatography with On-line Thermionic Detection

Abstract

The potential of a previously reported on-line reversed-phase liquid chromatography-thermionic detector (LC–TID) system has been further evaluated. Several trialkyl (trimethyl to tri-octyl) and triaryl (triphenyl and tri-o-cresyl) phosphates were chosen as model compounds. LC was done on an alkyl-bonded silica column with methanol-water (80:20) at a flow-rate of 35—70μ/min as eluent. The band broadening in the interface-TID unit increased with decreasing volatility of the compounds and for the relatively non-volatile compounds, the band broadening decreased with increasing eluent flow-rate.

For most of the test compounds, detection limits of 40–100pg were obtained. As an illustration of the high selectivity of the LC[sbnd]TID system, the trace-level determination of two aryl phosphates in sediment samples is reported.     

微乳液介质—雷氏盐浊度法测定汞的研究

研究了以乳化剂ＯＰ／正丁醇／正庚烷／水微乳液为介质，雷氏盐浊度法测定汞。微乳液的引入，使沉淀颗 粒分散均匀，体系稳定性显著提高，分析条件得到改善，体系可稳定１１ｈ。以４００ｕｍ为测定波长，汞量在０．０４～２．４ ｍｇ／Ｌ范围内线性关系良好。对痕量汞的测定可采用巯基葡聚糖凝胶（ＳＤＧ）进行分离富集，提高了测定的选择性和 灵敏度，用于实际样品测定，结果令人满意。     

抗氧化剂的毛细管电泳-间接化学发光联用在线评价方法研究

根据碱性条件下羟自由基与luminol反应会产生化学发光而抗氧化剂能够清除羟自由基从而抑制发光的原理, 结合毛细管电泳技术, 建立了一种针对多组分共存体系中抗氧化组分的在线评价的新方法. 对这种毛细管电泳-间接化学发光检测技术, 优化化学发光的各种条件, 考察了抗氧化剂硫脲和麻黄碱的抗氧化活性, 采用曲线拟合求出它们对羟自由基的半数清除浓度(IC₅₀), 得出抗氧化活性大小为麻黄碱＞硫脲, 这与荧光分光光度法的结果一致. 该方法初步应用于评价中药槐米提取物化学组分的抗氧化活性.     

亚硝基R盐和乙基紫高灵敏度分光光度法测定铋

乙基紫在酸性体系中作为显色剂已有不少报道,而在碱性中未曾见过.本法表观摩尔吸光系数7.73×10~6 L·mol~(-1)·cm~(-1),操作简便,用于试样分析,结果满意.     

重量法测定土壤水溶性盐总量的优化

土壤水溶性盐是表征土壤盐碱化程度的重要指标,也是评价耕地地力的重要参数,被纳入第三次全国土壤普查（“三普”）监测指标体系中。重量法是测定土壤水溶性盐总量的最常用方法,其测定过程易受多种因素影响,导致其测定结果不准。鉴于此,本文设计试验分别验证了水溶性盐浸提和浸提液固液分离这两个过程对测定结果的影响,结果表明浸提液固液分离是影响土壤水溶性盐总量测定准确度和精密度的主要因素。基于此进一步探究4种不同固液分离方式（布氏漏斗过滤、滤膜真空抽滤、离心、滤纸组合过滤）对测定结果的影响,结果表明相较于其它方式,滤纸组合过滤测定结果准确度高,适用于土壤水溶性盐总量的测定。对改进后的重量法测定土壤水溶性盐总量进行方法学确认,结果表明其检出限为0.01 g/kg,测定下限为0.04 g/kg;方法的准确度和精密度、适用范围等均符合相关要求。本文推荐的土壤水溶性盐总量测定方法为：土壤样品采用1:5土水比浸提,180 r/min振荡3 min,浸提液采用滤纸组合自然过滤;其测定结果的准确度和精密度符合相关要求。本文旨在为“三普”内业检测提供参考和借鉴,为全面摸清不同区域土壤水溶性盐含量水平及土壤盐渍化程度提供技术支撑。     

液相色谱-串联质谱法测定血清中15种胆汁酸

建立了血清中15种胆汁酸的液相色谱-串联质谱(LC-MS/MS)测定方法。血清样品经乙腈沉淀蛋白后,用Capcell Pak C18MG柱分离,以乙腈-醋酸铵缓冲液为流动相进行梯度洗脱,流速0.25 mL/min,进样10μL,采用多反应监测(MRM)定量分析。在定量范围内,15种胆汁酸的线性关系良好,批内、批间的RSD分别为2.3%~12.7%和1.1%~14.3%,回收率在75%~101%之间。应用本法测定了10名健康儿童血清中的胆汁酸含量。该方法的样品处理简单快速,检测准确灵敏,可满足临床血样中胆汁酸含量测定的要求。