Analysis of Spectinomycin by HPLC with Evaporative Light-Scattering Detection

A high-performance liquid chromatographic method with evaporative light-scattering detection (ELSD) has been developed for analysis of spectinomycin and related impurities. Separation of spectinomycin from structurally related impurities was achieved on a C₁₈ column. The optimized mobile phase was 25 mmol L⁻¹ ammonium acetate (pH 7.5)-methanol, 90:10 (v/v), at a flow rate of 0.6 mL min⁻¹. The temperature of the drift tube of the ELSD was 95°C and the flow rate of carrier gas was 2.2 L min⁻¹. The accuracy, specificity, precision, linearity, sensitivity, and robustness of the method were validated in accordance with ICH guidelines. In addition to determination of spectinomycin and related impurities, the method is also ideal for determination of the salts spectinomycin hydrochloride and spectinomycin sulfate.     

用反相离子对色谱-蒸发光散射检测法研究阿仑膦酸钠及其相关物质的分离

采用反相离子对色谱-蒸发光散射检测法,研究了阿仑膦酸钠及相关物质的色谱分离。选择的色谱条件是:固定相为Intersil C8(150×4.6 mm i.d.,5μm)柱,以52mmol.L-1正戊胺水溶液(用乙酸调节pH至7.0)-甲醇(98∶2,V/V)为流动相,流速为1.0 mL.min-1,柱温为室温。在该色谱条件下,阿仑膦酸钠与其有关物质(包括合成过程中残余的原料4-氨基丁酸、亚磷酸及分解产物磷酸盐)分离良好。本法简便、快速,为阿仑膦酸钠的常规分析及质量控制提供了一种可靠而有效的手段。     

Determination of Atazanavir in the Presence of its Degradation Products by a Stability-Indicating LC Method

A forced degradation study was successfully applied for the development of a stability-indicating assay method for the determination of atazanavir in presence of its degradation products. The method was developed and optimized by analyzing the forcefully degraded samples. Degradation of the drug was done under acidic, alkaline, oxidative, photolytic and thermal stress conditions. The proposed method was able to resolve all of the possible degradation products formed during the stress studies. The major impurities are generated in acidic and alkaline conditions. The product was found stable under thermal, photolytic and oxidative conditions. The developed method was validated for determination of atazanavir, and the method was found to be equality applicable to study the impurities formed during routine and forced degradation of atazanavir.     

Determination of Nitroglycerin and Its Degradation Products by Solid-Phase Extraction and LC–UV

The usual analytical method EPA 8330B cannot properly separate the four degradation products of nitroglycerin (mononitroglycerin, 2-mononitroglycerin, 1,2-dinitroglycerin and 1,3-dinitroglycerin). An analytical method for the determination of the degradation products of nitroglycerin in water using LC–MeOH was developed at 205 nm. The most suitable solid phase extraction cartridge was selected in order to reach the required detection level of these products in water. The combination of the extraction and LC analysis is sensitive and allows detection of nitroglycerin and its products at μg L^?1 level. The technique is straightforward and can help to understand the environmental fate of nitroglycerin.     

Performance Evaluation of Charged Aerosol and Evaporative Light Scattering Detection for the Determination of Ginsenosides by LC

A sensitive LC-CAD method was developed for simultaneous determination of seven major triterpenoid saponins, namely ginsenosides Rg₁, Re, Rb₁, Rc, Rb₂, Rb₃ and Rd in Panax ginseng C. A. Meyer, a commonly used traditional Chinese medicine. This CAD method was evaluated in sensitivity, linearity and reproducibility compared to ELSD and UV. It was found the developed method has improved sensitivity, linearity and reproducibility compared to ELSD. This method was successfully applied to analyze the ginsenosides in ten samples of Panax ginseng. The validation results indicated that the improved method can be utilized as another approach for quality control of P. ginseng.     

Determination of Apigenin by LC with Electrochemical Detection

A rapid, sensitive, and specific method for quantification of olmesartan, the prodrug of olmesartan medoxomil, in human plasma, using zidovudine as internal standard, is described. Sample preparation involved a simple solid-phase extraction procedure. The extract was analyzed by high-performance liquid chromatography coupled to electrospray tandem mass spectrometry (LC–MS–MS). Chromatography was performed isocratically on a 5 μm C₁₈ analytical column (50 mm × 4.6 mm i.d.) with water–acetonitrile–formic acid 20:80:0.1 (v/v) as mobile phase. The response to olmesartan was a linear function of concentration over the range 4.82–1,928 ng mL⁻¹. The lower limit of quantification in plasma was 4.82 ng mL⁻¹. The method was successfully applied in a bioequivalence study of an olmesartan formulation after administration as a single oral dose.     

离子排斥柱分离 /蒸发光散射检测同时测定天冬氨酸钾镁-山梨醇注射液中的天冬氨酸和山梨醇

 采用TSKgelOApak A离子排斥柱分离、蒸发光散射检测同时测定了天冬氨酸钾镁 山梨醇注射液中的天冬氨酸和山梨醇。在流动相为水 (含 0 1% (体积分数 )三氟乙酸 ) 甲醇 (体积比为 9∶1)溶液、柱温为室温的条件下 ,天冬氨酸和山梨醇的质量浓度为 2 0 0mg/L～ 2 0 0 0mg/L时与其峰面积具有良好的线性关系 (r =0 999)。该方法对天冬氨酸和山梨醇的检测下限分别为 30mg/L和 2 0mg/L。测定结果表明 ,该注射液的光、热稳定性非常好。     

反相高效液相色谱-蒸发光散射检测法测定紫苏子油中的α-亚麻酸

建立了反相高效液相色谱-蒸发光散射检测器(RP-HPLC-ELSD)测定紫苏子油中α-亚麻酸含量的方法。紫苏子油样用0.5 mol/L的KOH-CH3OH溶液于60 ℃水浴中皂化20 min、6 mol/L的盐酸酸化后用无水乙醚萃取,再用氮气流吹干乙醚，用甲醇溶解并定容,然后直接进行RP-HPLC-ELSD分析。结果表明,当α-亚麻酸质量为6.2～45.4 μg时,其峰面积A的对数(lg A)与α-亚麻酸质量m(μg)的对数(lg m)呈线性关系,线性方程为lg A=1.3675·lg m－1.628,相关系数为0.9973(n＝5)。以信噪比S/N=3计算,方法的检出限为0.11 μg。被分析的紫苏子油中α-亚麻酸的含量为6.79%(质量分数),相对标准偏差(RSD)为5.1%(n=5)；平均回收率为102%,RSD为6.3%(n=5)。该方法简单、快速、准确。     

First Determination of Glycidyl Ester Species in Edible Oils by Reverse-Phase Ultra-Performance Liquid Chromatography Coupled with an Evaporative Light-Scattering Detector

In this work, a new ultra-performance liquid chromatograph-evaporative light-scattering detector (UPLC-ELSD) method for quantitation of glycidyl esters (GE) contents in edible oils is presented. The method features complete separation of five GE species within 20 min by a C18 column and gradient elution with a mobile phase consisting of 85% and 2.5% methanol aqueous solutions. The coefficients of regression (R²) were all ≥0.9999 for the linear-quadratic regression curves of GE species in a concentration range of 5~80 μg/mL. The intraday and interday recoveries (%) of GE species in solvent were in a range of 81.3~107.3%, and the intraday and interday coefficients of variation (CVs, %) were all ≤8.6%. The average recovery (%) of GE species spiked in extra-virgin olive oil samples ranged from 88.3~107.8% and the intermediate precision (CV, %) of ≤14% indicated acceptable accuracy and precision. The method exhibited limit of quantification (LOQ) for each GE species (0.6 μg glycidol equivalents/g oil). The method was applied to determine GE concentrations of six commercial oil samples, and total glycidol equivalents were consistent with data obtained by GC-MS method. This UPLC-ELSD method could be adopted for precursory screening and research purposes to improve food safety when MS detectors are unavailable.     

反相高效液相色谱-蒸发光散射检测法测定紫苏子油中的α-亚麻酸

建立了反相高效液相色谱-蒸发光散射检测器(RP-HPLC-ELSD)测定紫苏子油中α-亚麻酸含量的方法。紫苏子油样用0.5m o l/L的KOH-CH3OH溶液于60℃水浴中皂化20m in、6m o l/L的盐酸酸化后用无水乙醚萃取,再用氮气流吹干乙醚,用甲醇溶解并定容,然后直接进行RP-HPLC-ELSD分析。结果表明,当α-亚麻酸质量为6.2~45.4μg时,其峰面积A的对数(lgA)与α-亚麻酸质量m(μg)的对数(lgm)呈线性关系,线性方程为lgA=1.367 5.lgm-1.628,相关系数为0.997 3(n=5)。以信噪比S/N=3计算,方法的检出限为0.11μg。被分析的紫苏子油中α-亚麻酸的含量为6.79%(质量分数),相对标准偏差(RSD)为5.1%(n=5);平均回收率为102%,RSD为6.3%(n=5)。该方法简单、快速、准确。     

亲水色谱-蒸发光散射检测器定量分析白坚木皮醇含量

建立白坚木皮醇(Quebrachitol)含量的亲水作用色谱-蒸发光散射检测器(ZICHILIC-ELSD)测定方法。Merck ZIC-HILIC色谱柱(150×4.6mm,5μm);以乙腈-水(体积比为70∶30)为流动相,等度洗脱,流速为1.0mL/min;蒸发光散射检测器,蒸发温度为65℃,雾化温度为50℃,高纯氮压力9.9 MPa。结果表明,白坚木皮醇浓度与其色谱峰面积积分值呈很好的线性关系,相关系数为0.9997。检测限为0.08mg/mL;相对标准偏差为0.48%;加标回收率为100.3%。该方法快速、简便、准确,适合从复杂体系中快速检测白坚木皮醇的含量。     

Ion-Pair Single-Drop Microextraction Determinations of Degradation Products of Chemical Warfare Agents in Water

Ion-pair single-drop microextraction (SDME) coupled to gas chromatography–mass spectroscopy (GC–MS) methods for the determination of four degradation products of chemical warfare agents were investigated in water. Acidic analytes were converted into their ion-pair complexes with cation surfactants in aqueous sample and then extracted into the organic single drop containing the derivatising agent. Upon injection, the analytes were derivatised in the GC injection hot port. Parameters, such as type of extraction solvent, ion-pairing (IP) reagent, reagent concentration, salt concentration, stirring speed and pH, were all optimized. This method is reproducible for spiked water sample for four different analytes (RSDs < 9.33 %, n = 5) and linear (r ² > 0.9945). The limit of detection (LOD) is in the range of 0.08–0.01 ng mL^?1 (S/N = 5) under GC–MS selected ion monitoring mode. The method was successfully applied to the proficiency test samples from the Organization for Prohibition of Chemical Weapons (OPCW).     

Ion-Pair Single-Drop Microextraction Determinations of Degradation Products of Chemical Warfare Agents in Water

Ion-pair single-drop microextraction (SDME) coupled to gas chromatography–mass spectroscopy (GC–MS) methods for the determination of four degradation products of chemical warfare agents were investigated in water. Acidic analytes were converted into their ion-pair complexes with cation surfactants in aqueous sample and then extracted into the organic single drop containing the derivatising agent. Upon injection, the analytes were derivatised in the GC injection hot port. Parameters, such as type of extraction solvent, ion-pairing (IP) reagent, reagent concentration, salt concentration, stirring speed and pH, were all optimized. This method is reproducible for spiked water sample for four different analytes (RSDs < 9.33 %, n = 5) and linear (r ² > 0.9945). The limit of detection (LOD) is in the range of 0.08–0.01 ng mL⁻¹ (S/N = 5) under GC–MS selected ion monitoring mode. The method was successfully applied to the proficiency test samples from the Organization for Prohibition of Chemical Weapons (OPCW).

     

Identification and Determination of Nicorandil and its Degradation Products by HPLC and GC/MS

Nicorandil [N-(2-hydroxyethyl)-nicotinamide nitrate NIC] is a novel kind of compound in the treatment of angina pectoris. NIC can be degraded easily in storage. The degradation products include N-(2-hydroxyethy) nicotinamide (HN), nitrate ion (NI), and ni…     

Determination of Brassinolide Analogs by High-Performance Liquid Chromatography with Evaporative Light Scattering Detection

An efficient method based on high-performance liquid chromatography with evaporative light scattering detection was developed for the separation and determination of four brassinolide analogs [24-epibrassinolide, (22S, 23S)-24-epibrassinolide, 28-homobrassinolide, and (22S, 23S)-28-epihomobrassinolide] without prior derivatization. The optimized analysis was carried out on a C₁₈ reversed-phase column (150 mm × 4.60 mm, 3 µm) at 30°C using isocratic elution of acetonitrile and water (38:62, v/v). The drift tube temperature of the detector was 60°C and the auxiliary gas (nitrogen) pressure was 360 kPa. The regression equations revealed linear relationships (R² = 0.9984–0.9994) within the test ranges. The limits of detection and quantification were in the ranges of 0.12 to 0.17 µg and 0.24 to 0.33 µg, respectively. The fully validated method was applied to quantify the active ingredient content in technical material and formulations and provides an alternative approach for quality control.     

Determination of Phenolic Acids in Danshen Preparations by LC with Chemiluminescence Detection

A simple and sensitive method has been developed for the simultaneous determination of eight phenolic acids in Danshen preparations based on liquid chromatography with chemiluminescence detection. Chemiluminescence parameters including flow rate, buffer pH, the concentration of luminescent and reactive solutions, were optimized. The analytical performance of the optimized luminol-H₂O₂ detection was compared with those of luminol-pyrogallol and UV detection. Under the optimized conditions, the method was validated with respect to linearity, precision, limits of detection and quantification. The method offers an attractive alternative to be used to evaluate the quality of Danshen preparations.     

GLC and HPLC Determination of Diazepam and its Degradation Products in Pharmaceutical formulations

Abstract

Stability-indicating high performance liquid chromatographic (HPLC) and gas-liquid chromatographic (GLC) assays for diazepam in pharmaceutical formulations are described. In HPLC method, the material is extracted with 5 % aqueous methanol and chromatographed on a dimethyloctyl stationary phase using methanol-water-acetic acid (80: 20: 1) and propyl paraben internal standard. The system separated diazepam from the main degradation products, desmethyl diazepam (a synthetic precursor of diazepam) and the excipients present in ampoules and syrups. The GLC method included the extraction of diazepam and 2-methylamino-5-chiorobenzo-phenone (MACB) from aqueous acidic solution into chloro form leaving the other degradation products in the aqueous phase. The chloroform extract is evaporated to dryness, dissolved in chloroform containing diethylhexyl phtha-late as internal standard and chromatographed on an OV-17 stationary phase using flame ionisation detector. The results are compared with the BP method described for each formulation.     

Simultaneous Determination of Safingol and d-erythro-Sphinganine in Human Plasma by LC with Fluorescence Detection

l-threo-Sphinganine (safingol) is a putative synthetic sphingosine kinase inhibitor currently being tested in clinical trials as an anticancer agent. To enable defining the pharmacokinetic properties of safingol in humans, we developed a sensitive analytical method to simultaneously quantitate safingol and its naturally-occurring diastereomer, d-erythro-sphinganine in human plasma. Of the two different fluorogenic derivatization agents (NDA and OPA) and several pH conditions compared for the derivatization, we found that NDA derivatization achieved more than 20 times greater sensitivity compared with OPA derivatization, and pH 9.0 showed the highest sensitivity for both compounds. An analytical method for liquid chromatography (LC) with a fluorescence detector (FLD) was developed and validated with calibration curve ranges of 20–1,000 ng mL^?1 for safingol and d-erythro-sphinganine. Our LC-FLD method using NDA-derivatization enabled simultaneous quantification of safingol and its naturally-occurring diastereomer, d-erythro-sphinganine with satisfactory sensitivity in human plasma.     

Simultaneous Determination of Safingol and d-erythro-Sphinganine in Human Plasma by LC with Fluorescence Detection

l-threo-Sphinganine (safingol) is a putative synthetic sphingosine kinase inhibitor currently being tested in clinical trials as an anticancer agent. To enable defining the pharmacokinetic properties of safingol in humans, we developed a sensitive analytical method to simultaneously quantitate safingol and its naturally-occurring diastereomer, d-erythro-sphinganine in human plasma. Of the two different fluorogenic derivatization agents (NDA and OPA) and several pH conditions compared for the derivatization, we found that NDA derivatization achieved more than 20 times greater sensitivity compared with OPA derivatization, and pH 9.0 showed the highest sensitivity for both compounds. An analytical method for liquid chromatography (LC) with a fluorescence detector (FLD) was developed and validated with calibration curve ranges of 20–1,000 ng mL⁻¹ for safingol and d-erythro-sphinganine. Our LC-FLD method using NDA-derivatization enabled simultaneous quantification of safingol and its naturally-occurring diastereomer, d-erythro-sphinganine with satisfactory sensitivity in human plasma.

     

胶束液相色谱法测定乳制品中三聚氰胺

采用胶束液相色谱法直接测定乳制品中三聚氰胺。考察了表面活性剂的种类及浓度、有机改性剂种类及用量、柱温、流动相pH值等对三聚氰胺色谱保留时间的影响。结果表明:随着有机改性剂增加、十二烷基硫酸钠(SDS)浓度增大和流动相pH值增大,三聚氰胺的容量因子(k′)明显减小。在所选定的条件下,三聚氰胺与乳制品中其他组分之间具有较好的分离效果。三聚氰胺质量浓度在0.1～100 mg·L~(-1)范围内呈线性关系,检出限(3S/N)和测定下限(10S/N)分别达0.02,0.07 mg·kg~(-1)。对同一试样的9次平行测定结果的相对标准偏差为1.28%,平均加入回收率为97.64%～99.91%。