A simple method for nicardipine hydrochloride quantification in plasma using solid-phase extraction and reversed-phase high-performance liquid chromatography

A simple and sensitive reversed-phase liquid chromatography method was developed and validated for the determination of nicardipine hydrochloride (NC) in rabbit plasma. Nicardipine hydrochloride and nimodipine, used as internal standard, were initially extracted from plasma by a rapid solid-phase extraction using C(18) cartridges. After extraction, nicardipine hydrochloride was separated by HPLC on a C(18) column and quantified by ultraviolet detection at 254 nm. A mixture of acetonitrile-0.02 M sodium phosphate buffer-methanol (45:40:15) with 0.2% of triethylamine of pH of 6.1 was used as mobile phase. The mean (+/-SD) extraction efficiency of NC was 77.56 +/- 5.4, 84.23 +/- 4.32 and 83.94 +/- 3.87% for drug concentrations of 5, 25 and 100 ng/mL, respectively. The method proved to be linear in the range of 5-100 ng/mL with a regression coefficient of 0.9993. The relative standard deviations of intra- and inter-day analysis for NC in plasma were 3.26-6.52% (n = 5) and 4.71-9.38% (n = 5), respectively. The differences of the mean value measured from the concentration prepared, expressed in percentages (bias percentage), were only - 5.2, 0.4 and 0.8% at NC 5, 25 and 50 ng/mL, which confirmed the accuracy of the method. The analytical technique was used to determine NC plasma concentration after drug oral administration to rabbits. The results inferred that NC is rapidly absorbed in rabbits and has a short half-life (t(1/2) = 1.34 h).     

Quantification of myrislignan in rat plasma by solid-phase extraction and reversed-phase high-performance liquid chromatography

A rapid and simple reversed-phase high-performance liquid chromatographic (RP-HPLC) method has been developed for determination of myrislignan in rat plasma after intravenous administration. The analytes extracted from plasma samples by solid-phase extraction were successfully carried out on a Diamonsiltrade mark ODS C(18) column (250 x 4.6 mm i.d., 5 microm) with an RP(18) guard column (8 x 4.6 mm i.d., 5 microm) and a mobile phase of MeOH-H(2)O (4:1, v/v). The UV detector was set at a single wavelength of 270 nm. The linear ranges of the standard curves were 0.5-30.0 microg/mL with the correlation coefficients greater than 0.9992. The lower limits of detection and quantification were 0.1 and 0.3 microg/mL for myrislignan. Intra- and inter-day precisions were 2.4-7.5 and 1.3-5.7%, respectively. The extraction recovery from plasma was more than 90%. This assay method has been successfully used to study the pharmacokinetics of myrislignan in rats.     

基于溶胶凝胶技术的在线固相萃取与高效液相色谱联用测定饮用水中的雌激素残留

建立了固相萃取与高效液相色谱在线联用测定水样中3种雌激素(己烯雌酚、己烷雌酚、双烯雌酚)痕量残留的方法。以溶胶凝胶技术合成的聚合物为固相萃取材料,对水样中的雌激素进行萃取富集,考察了样品溶液不同pH、上样流速及洗脱溶剂等条件对合成材料富集效果的影响。结果表明,在优化的条件下,该方法对3种雌激素的检出限(S/N=3)为0.07~0.13 μg/L,样品中的加标回收率为82.31%~99.43%,相对标准偏差(RSD)为1.61%~7.15%。方法简便可靠,适用于饮用水中雌激素的痕量残留检测。     

改进的固相萃取-高效液相色谱法测定土壤中15种醛酮类化合物北大核心CSCD

建立了改进的固相萃取-高效液相色谱法测定土壤中甲醛、乙醛、丙烯醛、丙酮、丙醛、丁烯醛、丁醛、苯甲醛、异戊醛、正戊醛、邻-甲基苯甲醛、间-甲基苯甲醛、对-甲基苯甲醛、正己醛和2,5-二甲基苯甲醛等15种醛酮类化合物的分析方法。利用乙腈对土壤进行超声提取,样品提取液与2,4-二硝基苯肼(2,4-DNPH)进行衍生化反应,生成稳定的腙类化合物;随后利用装有亲水亲脂平衡的N-乙烯基吡咯烷酮/二乙烯基苯共聚物填料的固相萃取小柱(Welchrom^(■)BRP)对衍生后的溶液进行净化;采用Ultimate^(■)XB-C_(18)色谱柱(250 mm×4.6 mm,5μm)进行分离,以乙腈-水(65∶35,v/v)为流动相进行等度洗脱,于波长360 nm处进行检测,利用外标法对土壤中15种醛酮类化合物进行定量。该方法改进了环境标准HJ 997-2018《土壤和沉积物醛、酮类化合物的测定高效液相色谱法》中试样的处理方法,优化后得到土壤的最佳提取条件,即:提取溶剂为乙腈,提取温度为30℃,提取时间为10 min。结果表明:采用BRP小柱的净化效果明显优于普通硅胶基质C_(18)小柱,15种醛酮类化合物在各自的范围内线性关系良好,线性相关系数均在0.996以上;平均加标回收率为84.6%~115.9%,相对标准偏差(RSD)为0.2%~5.1%;检出限为0.02~0.06 mg/L。该方法简便,灵敏度高,准确性好,适用于HJ 997-2018中规定的土壤和沉积物中15种醛酮类化合物的准确定量分析,为研究土壤中醛酮类化合物的残留状况和环境行为提供了可靠的技术支持。     

Determination of andrographolide and dehydroandrographolide in rabbit plasma by on-line solid phase extraction of high-performance liquid chromatography

The high-performance liquid chromatography (HPLC) coupled with on-line solid phase extraction (SPE) and ultraviolet (UV) detection was developed for determining andrographolide and dehydroandrographolide in rabbit plasma. Plasma samples (100 μL) were injected directly into a C18 SPE column and the biological matrix was washed out for 6 min using 15% aqueous methanol. By rotation of the switching valve, andrographolide and dehydroandrographolide were eluted in the back-flush mode and transferred to the analytical column by the chromatographic mobile phase consisted of methanol:acetonitrile (ACN):water (50:10:40; v/v). The UV detection was performed at 225 nm. The calibration curves showed excellent linear relationship (R ≥ 0.9993) over the concentration range of 0.05-5.0 μg mL⁻¹. The within- and between-day precisions (R.S.D.) of two analytes were in the range of 1.2-6.5% and the accuracies were between 92.0% and 102.1%. Their recoveries were all greater than 94%. The limits of detection were 0.019 μg mL⁻¹ for andrographolide and 0.022 μg mL⁻¹ for dehydroandrographolide. This method was successfully applied to the plasma concentration-time curve study after oral administration of Andrographis paniculata Nees extract in rabbit.     

Improvement of cyclosporin A determination in whole blood by reversed-phase high-performance liquid chromatography

A chromatographic method was developed for the determination of cyclosporin A in human whole blood using reversed-phase HPLC at room temperature. Most previous reports carried out this liquid chromatographic separation at temperatures above 70 degrees C. The present procedure greatly improves the detection limit by controlling peak broadening effects, as well as the lifetime of the column at room temperature. Under optimal conditions and using ketoconazole as an internal standard, the calibration graph was linear in the range of 16-1000 microg/L with a relative standard deviation of 3.72% at 150 microg/L and 2.45% at 300 microg/L (n = 11) of cyclosporin A. The detection limit was of 5.0 microg/L cyclosporin A. By this procedure, cyclosporin A pharmacokinetic parameters in healthy Chinese subjects were studied. The developed method could be applied to the quantification of cyclosporin A in human blood samples and allows the study of its pharmacokinetics in routine laboratories.     

Determination of sulfonamides in livers using matrix solid-phase dispersion extraction high-performance liquid chromatography

The matrix solid-phase dispersion (MSPD) was applied for extracting seven sulfonamides (SAs) in liver samples. The separation and determination were carried out by high-performance liquid chromatography. The analytes were derivated with fluorescamine and detected with fluorescence detector. The types of dispersion adsorbents for MSPD were examined and the highest recovery was obtained when the diatomaceous earth was used as the dispersion adsorbent and the mass ratio of dispersion adsorbent to sample was 3:1. The acetone was used as the elution solvent. Under the optimal conditions, the linear range for determining the SAs in liver samples was 5.0-1000.0 ng/g. The porcine, chicken and cattle liver samples were analyzed and the average recoveries of seven SAs were higher than 84.6%.     

Determination of ethylenediaminetetraacetic acid in sea water by solid-phase extraction and high-performance liquid chromatography

The chelating agent EDTA is widely used, and as a result is showing up widely in the aquatic environment. Here we describe a preconcentration procedure for measuring EDTA concentration in sea water samples by HPLC. The procedure consists of forming an Fe(III) complex followed by solid-phase extraction using an activated carbon cartridge. After the preconcentration, EDTA was quantified by HPLC with ultraviolet detection (260 nm). The enrichment permitted the determination of EDTA at concentrations as low as 1 nM. Good recoveries were obtained for both brackish and full-strength sea water with high repeatability (RSD < 6%). The method was applied to sea water samples taken from near the mouth of the Oyabe River in Japan.     

Determination of triptolide and triptonide in human plasma by high-performance liquid chromatography

An isocratic high-performance liquid chromatographic method for determination of triptolide and triptonide in human plasma is described. Plasma samples were extracted with OasisHLB solid-phase extraction (SPE) cartridges. After pretreatment, they were separated on a SymmetryShieldRP(18) column with a mobile phase of acetonitrile-water (40:60,v/v) at 40 degrees C. The effluent was monitored at UV 217 nm. Linearity (0.010-1.0 mg/L) was good, and the lower limit of detection was 3 ng/mL for triptolide and 4.5 ng/mL for triptonide (S/N = 3). The relative standard deviations of intra- and inter-day assay were less than 15% and the recoveries were better than 80%. The developed method was applied to the determination of triptolide and triptonide concentration in a patient's plasma after taking the medicament containing Tripterygium wilfordii Hook. F.     

Determination of hyperoside and isoquercitrin in rat plasma by membrane-protected micro-solid-phase extraction with high-performance liquid chromatography

A novel method, micro‐solid‐phase extraction based on membrane‐protected molecularly imprinted polymer, was developed to extract hyperoside and isoquercitrin in rat plasma. Synthesized hyperoside MIPs were packed in a porous polyether sulfone membrane envelope to perform extraction. The parameters sorbent materials, membrane types, extraction time and desorption conditions were optimized for micro‐solid‐phase extraction. Under the optimal conditions, correlation coefficients, 0.998 and 0.999, were obtained for hyperoside and isoquercitrin, respectively, with the linear range between 1 and 120 μg/mL. The absolute extraction recoveries from 84.5 to 89.3% were found. The method detection limits of hyperoside and isoquercitrin were 0.24 and 0.22 μg/mL, respectively. Compared with traditional methods, solid‐phase extraction, liquid–liquid extraction and protein precipitation, the developed method was simple, highly efficient for extraction, environmentally friendly, and particularly suitable for complex biological samples.     

在线净化/固相萃取-高效液相色谱法测定饮用水和环境水体中的百草枯和敌草快

建立了在线净化/固相萃取(SPE)-高效液相色谱(HPLC)快速、准确测定饮用水和环境水体中的两种痕量除草剂百草枯和敌草快的方法。样品用大体积自动进样器注入在线净化小柱并流经固相萃取小柱,通过双梯度高效液相色谱系统中的上样泵实现净化和富集后,通过阀切换将固相萃取小柱切换至分析流路中;用分析泵将待测物从富集柱冲洗至分析柱进行测定。上样泵流速和分析泵流速分别为0.7和0.6 mL/min,采用等度洗脱方式完成两种除草剂的分离和检测。检测波长分别为260 nm (百草枯)和311 nm (敌草快),进样体积为2.5 mL,整个分析时间为16 min。该方法在1.0～20 μg/L范围内线性关系良好,两种除草剂的线性相关系数均大于0.9980,检出限分别为0.10和0.12 μg/L(S/N=3)。该方法前处理简单,快速,可用于饮用水和环境水体中痕量除草剂的测定。     

A high-performance liquid chromatographic method for saikosaponin a quantification in rat plasma

A high-performance liquid chromatographic method with UV detection has been developed for the determination of saikosaponin a in rat plasma. Saikosaponin a and internal standard jujuboside A were isolated from plasma samples by solid-phase extraction. The chromatographic separation was achieved on a reversed-phase C(18) column with the mobile phase of acetonitrile-water (35:65, v/v) at a flow rate of 1 mL/min and UV detection was set at 205 nm. The standard curve for saikosaponin a was linear over the concentration range 0.25-10 microg/mL and the limit of detection was 0.05 microg/mL. The absolute recovery was greater than 82%. The precision and accuracy ranged from 3.05 to 9.59% and 95.61 to 110.00%, respectively. The validated method was used to determine saikosaponin a in plasma samples in a pharmacokinetic study of saikosaponin a administered to Sprague-Dawley rats.     

固相萃取-高效液相色谱检测葡萄酒中赭曲霉毒素A

使用C18小柱固相萃取, C18反相柱(250 mm×4.6 mm i.d.)分离,V(乙腈):V(水):V(乙酸)＝99:99:2为流动相,荧光检测器(激发波长333 nm,发射波长460 nm)检测,测定葡萄酒中赭曲霉毒素A.其质量浓度在6.25～200 ng/mL范围内呈良好线性,相关系数为0.9997.样品经浓缩60倍后,方法检出限为0.027 ng/mL.对红葡萄酒、干红及白葡萄酒进行了加标回收实验,回收率为80.1%～109.8%.平行7份样品加标回收率相对标准偏差为5.9%.对市售6种葡萄酒进行了赭曲霉毒素A的测定.     

高效液相色谱法测定柑橘和土壤中残留的多菌灵

建立了柑橘和土壤中多菌灵残留量的高效液相色谱(HPLC)分析方法。柑橘果肉、果皮、全果和土壤样品中残留的多菌灵用碱性乙腈溶液提取,经NH2固相萃取(SPE)柱净化,HPLC分离,紫外检测器检测,外标法定量。在0.02～5.0 mg/L范围内,多菌灵的峰面积与其质量浓度呈良好的线性关系,相关系数为0.9997。柑橘果肉、果皮、全果和土壤中添加0.05～0.5 mg/kg多菌灵标准品的平均回收率为89.2%～102%,相对标准偏差为1.8%～9.1%;柑橘果肉和土壤中多菌灵的最低检测浓度为0.05 mg/kg,柑橘果皮和全果中多菌灵的最低检测浓度为0.1 mg/kg。该方法的灵敏度、准确度和精密度均符合农药残留测定的技术要求。     

Investigation of copper-azamacrocyclic complexes by high-performance liquid chromatography

The use of copper radioisotopes in imaging and therapy has prompted an increased interest in chelators which form stable copper complexes, such as Cu(II)-azamacrocyclic complexes. The effects of charge, stability and the size of the macrocyclic backbone of the Cu(II)-azamacrocyclic complexes on biological behavior have been evaluated. Here we report a reversed-phase high-performance liquid chromatography (HPLC) method to separate several Cu(II)-azamacrocyclic complexes, including Cu(II) complexes of 1,4,8,11-tetraazacyclotetradecane-1,4,8,11-tetraacetic acid (TETA), 4,11-bis(carboxymethyl)-1,4,8,11-tetraazabicyclo[6.6.2]hexadecane (CB-TE2A) and 4,10-bis(carboxymethyl)-1,4,7,10-tetraazabicyclo[5.5.2]tetradecane (CB-DO2A). Absorbance at 280 nm was used to monitor the complexes as they eluted from the reversed-phase column. The effects of the concentration of the buffer, the pH of the buffered mobile phase and the concentration of the organic modifier, methanol, on the separation were investigated. Separation of these copper complexes by ion-pair HPLC with the use of a mass spectrometry-compatible ion-pair reagent, triethylammonium acetate, in the mobile phase at pH 6.3 is also presented. The reversed-phase chromatographic conditions utilized also allow the pK(a)s of Cu-TETA and the log(k'w) values of Cu-CB-TE2A, Cu-TETA and Cu-CB-DO2A to be estimated.     

Simultaneous determination of oxycodone and its major metabolite, noroxycodone, in human plasma by high-performance liquid chromatography

Oxycodone (14-hydroxy-7,8-dihydrocodeinone) is a potent opioid receptor agonist. In the present study, a liquid-liquid extraction-based reversed-phase HPLC method with UV detection was validated and applied for the analysis of oxycodone and its major metabolite, noroxycodone, in human plasma. The analytes were separated using a mobile phase, consisting of acetonitrile and phosphate buffer (8:92, v/v) at a flow rate of 1 mL/min, and UV detection at 205 nm. The retention times for oxycodone, noroxycodone and codein (internal standard) were 14.7, 13.8 and 10.2 min, respectively. The validated quantitation range of the method was 2-100 ng/mL for oxycodone and 10-100 ng/mL for noroxycodone. The developed procedure was applied to assess the pharmacokinetics of oxycodone and its metabolite following administration of a single 20 mg oral dose of oxycodone hydrochloride to one healthy male volunteer.     

Determination of cephalosporin antibiotics in water samples by optimised solid phase extraction and high performance liquid chromatography with ultraviolet detector

A reliable and robust analytical method based on solid phase extraction (SPE) and high performance liquid chromatography (HPLC) with ultraviolet (UV) detector was developed for the simultaneous determination of five cephalosporin antibiotics (Ceftazidime, Cefradine, Cefaclor, Cefotaxime and Cefoperazone) in various water samples. Under optimised conditions, it was applicable to preconcentrate up to 500?ml of water samples in the OASIS HLB cartridges with reasonable recoveries for all the cephalosporin antibiotics tested. Recoveries were as follows: deionised water, tap water and groundwater, between 84.2 and 98.9%; surface water, between 71.2 and 81.0%; influent and effluent of wastewater treatment plant (WWTP), between 56.9 and 72.1%. The method detection limits (MDLs) for different water samples were in the range of 26 to 59?ng?l^?1. Real water samples were analysed using the proposed approach to demonstrate the applicability and validation. Negative results were obtained for the tap water and groundwater. However, all the selected cephalosporin antibiotics were identified in the influent and effluent of a local WWTP at ng?l^?1–µg?l^?1 level. In addition, Ceftazidime was found in surface water with a concentration of 0.75–2.60?µg?l^?1. The results indicate that the ‘pseudo-persistent’ contamination of cephalosporin antibiotics in the water environment could not be neglected.     

固相萃取-高效液相色谱法测定水果和果酱中的6种对羟基苯甲酸酯

建立了固相萃取-高效液相色谱(SPE-HPLC)同时测定水果和果酱中6种对羟基苯甲酸酯(对羟基苯甲酸甲酯、对羟基苯甲酸乙酯、对羟基苯甲酸异丙酯、对羟基苯甲酸丙酯、对羟基苯甲酸异丁酯和对羟基苯甲酸丁酯)含量的方法。经Oasis HLB固相萃取柱净化的样品采用HPLC分离,优化的色谱条件为采用Symmetry-C18色谱柱分离,流动相为柠檬酸缓冲液-甲醇(体积比为48:52),流速1.0 mL/min,检测波长258 nm,测定温度40 ℃。6种对羟基苯甲酸酯的线性范围为0.1～20.0 mg/L(r=0.9999),回收率为82.8%～115.5%,相对标准偏差为0.2%～6.8%(n=6)。对羟基苯甲酸甲酯、对羟基苯甲酸乙酯、对羟基苯甲酸异丙酯、对羟基苯甲酸丙酯的检出限(S/N=3)为0.1 mg/kg,定量限(S/N=10)为0.3 mg/kg;对羟基苯甲酸异丁酯和对羟基苯甲酸丁酯的检出限为0.2 mg/kg,定量限为0.6 mg/kg。该方法简便快速、结果准确、重现性好,可作为测定水果及果酱中多种对羟基苯甲酸酯的有效方法。     

高效液相色谱法同时检测8种喹诺酮类兽药残留量

建立了吡哌酸、氧氟沙星、环丙沙星、单诺沙星、恩诺沙星、沙拉沙星、(噁)喹酸和氟甲喹8种喹诺酮类兽药残留量的高效液相色谱-荧光检测方法. 方法的线性范围: 30～2000 μg/kg, 定量限为30 μg/kg, 检出限为5 μg/kg (吡哌酸为20 μg/kg). 该方法采用基质分散和微波萃取技术进行样品的前处理, 回收率为70.0%～99.5%, 相对标准偏差1.0%～8.5%. 并同固相萃取方法进行了比较, 分别使用了RPS、HLB、MAX 3种固相萃取柱, 其回收率均低于本法. 确立了以Aglient XDB-C18 (5 μm, 150 mm×4.6mm i.d.)色谱柱, H3PO4-纯水-三乙胺-乙腈(pH 3.0)为流动相的最佳色谱条件, 吡哌酸、氧氟沙星、环丙沙星、单诺沙星、恩诺沙星、沙拉沙星的检测波长为: 激发波长285 nm, 发射波长460 nm;(噁)喹酸和氟甲喹为: 激发波长325 nm, 发射波长365 nm. 方法可满足兽药残留检测要求.     

基于十八烷基三甲基溴化铵修饰的磁性粒子在线磁性固相萃取-高效液相色谱法测定水样中磺酰脲类农药

采用溶胶-凝胶法制备表面修饰了十八烷基三甲基溴化铵的磁性粒子作为萃取剂，研制了一种在线磁性固相萃取（on-line MSPE）装置，建立了on-line MSPE与高效液相色谱联用测定水样中两种磺酰脲类农药（氯磺隆、苄嘧磺隆）的方法。实验优化了在线磁性固相萃取条件并进行方法学考察，证明该方法具有良好的线性关系（两种目标物的线性相关系数均≥ 0.9997）和较低的检出限（两种目标物的检出限分别为0.32和1.12 μg/L）。将此法用于3种环境水样中两种磺酰脲类农药的检测，水样中均检出氯磺隆，均未检出苄嘧磺隆。两种目标物加标回收率为70.0%~113.4%。该方法高效、简便，在分离富集环境水样中磺酰脲类农药方面有一定的应用前景。