光度法测定槟榔中槟榔碱的含量

采用柱色谱法从槟榔中提取分离槟榔碱,用红外(1R)、核磁(HNMR)、质谱(MS)法确证其结构。采用溴甲酚绿光度法测定槟榔碱的含量,线性回归方程为A=7.160×10~(-3)c-0.0328,相关系数r=0.9954,线性范围为19.5～112.1μg/ml。对样品进行测定,相对标准偏差为0.556％,回收率为96.9％～102.8％。     

液相色谱法测定槟榔饮片中槟榔碱含量的不确定度评定

根据《测量不确定度评定与表示》对液相色谱法测定槟榔饮片中槟榔碱含量的不确定度进行评定。通过分析得出,体积类不确定度是主要影响因素。分析结果表明,当槟榔饮片中槟榔碱含量为0．58％时,其扩展不确定度为0．02％（k=2）     

高效毛细管电泳法测定中草药川乌、草乌中乌头碱的含量

建立了测定有毒中草药川乌和草乌中３种乌头碱的高效毛细管电泳方法,系统地考察了电泳条件对分离的影响,并应用于香港市售川乌及草乌中中乌头碱、次乌头碱和乌头碱的测定。检测限为１．６７～２．３１ｍｇ／Ｌ,回收率为９３．０％～１０４．０％,相对标准偏差为０．６８％～１．７０％。     

高效毛细管电泳地测定中草药川乌,草乌中乌头碱的含量

建立了测定有毒中草药川乌和草乌中３种乌头碱的高效毛细管电泳方法,系统地考察了电泳条件对分离的影响,并应用于香港市售川乌及草乌中中乌头碱、次乌头碱和乌头碱的测定,检测限为１．６７－２．３１ｍｇ／Ｌ,回收率为９３．０－１０４．０％,相对标准差为０．６８－１．７０％。     

兴奋剂马钱子碱的电化学氧化及其伏安法测定

以玻碳电极为工作电极，硫酸钾为支持电解质，在合适的ｐＨ条件下，通过循环伏安法，首次观测到了马钱子碱的不可逆氧化峰。在浓度为２０×１０－４～４０×１０－３ｍｏｌ／Ｌ范围内其峰电流与浓度呈线性关系，检测限为１０×１０－５ｍｏｌ／Ｌ。在正常人体的尿样中，采用标准加入法进行回收实验，其平均回收率为１００８％。该法简便、快速，用５０×１０－４ｍｏｌ／Ｌ的马钱子碱溶液重复测定１０次，相对标准偏差为１８％。对其反应机理作了初步探讨。     

植物生物分子的电分析化学研究X槟榔碱电化学行为及测定

槟榔碱主要存在于棕榈科植物槟榔的种子内。槟榔是我国目前亟待开发的天然植物资源,广泛分布于海南、广西、云南、福建及台湾等地。槟榔碱味辛、温,具有杀虫、破积、下气、行水的功能。由于槟榔碱对M—胆碱受体的作用,平时嚼食槟榔,可促使唾液分泌增加、增进     

离子交换分离－氢化物原子吸收光谱法测定紫铜中微是量硒

采用阳离子交换树脂离子分离铜，发生氢化物原子吸收光谱法测定硒。上柱溶液酸度在０～７％，硒的回收率在９６～１０１％，过柱溶液中铜的浓度低于０．０１μｇ／ｍＬ。方法检出限为５×１０￣（－５）％，分析紫铜中４．４×１０￣（－４）％的硒，相对标准偏差为３％。     

希夫碱类药物中间体的二次微分示波计时电位法测定

建立了应用微机化的二次微分交流示波计时电位法直接测定希夫碱类药物中间体含量的方法。二次微分示波曲线上Ｎ－（２－苯并噻唑）－２－羟基苯甲亚胺、Ｎ－（２－苯并噻唑）－２－羟基－４－溴苯甲亚胺、Ｎ－（２－苯并噻唑）－２－羟基－４－氯苯甲亚胺３种希夫碱峰高与其浓度分别在２７．２～１３６ｒｍｏｌ／Ｌ、４７．０～１１３ｕｍｏｌ／Ｌ和１８．０～１１４ｕｍｏｌ／Ｌ范围内呈线性,相对标准偏差不大于６．０％（n＝３）     

示波极谱法快速测定食品用橡胶制品,铝制品中的锌

根据在０．０６８￣０．２３８ｍｏｌ／Ｌ乙酸底液中,锌在滴汞电极上产生一灵敏的极谱还原波,峰电位（Ｅ）为－１．０９Ｖ（ｖｓ,ＳＣＥ）建立了单扫示波极谱法,用于快速测定食品用橡胶制品,铝制品中的锌,该法的回收率为９０．６％￣１０６％,相对标准偏差（ＲＳＤ）为１．０％￣４．３％。     

串联质谱法快速分析皮革中五氯酚残留

建立了皮革样品中五氯酚的串联质谱分析方法,以ｍ／ｚ２６６为母离子,碰撞电压为０．８Ｖ,以子离子ｎ／ｚ２３０为定量离子,外标法定量。线性范围为０．１￣１０．０ｍｇ／Ｌ,检出限为０．００５ｍｇ／ｋｇ,回收率为８５．４％￣１０２．５％,相对标准偏差为２．５５％￣３．５５％。方法具有快速、准确的特点。     

Characterization of protein adducts formed by toxic alkaloids by nano‐scale liquid chromatography with mass spectrometry

Betel quid chewing is associated with cytotoxicity, genotoxicity and carcinogenicity in diseases such as oral cancer, liver cirrhosis, hepatocellular carcinoma and diabetes mellitus. Arecoline and arecaidine, which are the main alkaloids in the areca nut, are potential exposure biomarkers in habitual betel quid users. This study developed a method of detecting arecoline‐ and arecaidine‐protein adducts by mass spectrometry (MS). First, bovine serum albumin was used to predict and confirm the binding sites of proteins modified by arecoline or arecaidine. Cells were then treated with arecoline to identify new protein adducts after cellular metabolic processing. Finally, human plasma was used to model long‐term exposure to arecoline and arecaidine. Following isolation proteins were tryspin digested. The peptides afforded were separated and analyzed by nano‐scale liquid chromatography with MS using an LTQ Orbitrap mass spectrometer. The experimental findings showed that cysteine is the predominant amino acid in protein adduct formation. The goal of this study was to establish a screening platform for identifying novel protein adducts that form covalent bonds with arecoline or arecaidine. Use of this strategy to survey new protein‐toxic adducts may help to identify novel biomarkers of betel nut exposure. Copyright © 2012 John Wiley & Sons, Ltd.     

High-performance liquid chromatographic determination of arecoline in human saliva

Arecoline (methyl-1,2,5,6-tetrahydro-1-methyl nicotinate) is an alkaloid found in the areca catechu nut which is a major component of the 'betel quid' chewed by a large proporation of the population in India, South Asia and the South Pacific islands. It is commonly associated with the development of oral leukoplakia, oral submucous fibrosis and oral cancer. We have developed a new ion-pairing reversed-phase high-performance liquid chromatographic (HPLC) method for the determination of arecoline in saliva, using arecaidine (1,2,5,6-tetrahydro-1-methylnicotinic acid) as an internal standard. The optimal wavelength was established using UV absorbance scans. It was showed that 215 nm is the optimal wavelength to maximise the signal in detecting arecoline in the mobile phase. Arecoline was extracted from saliva with hexane-isoamyl alcohol (1%) and reconstituted with mobile phase for HPLC analysis. The developed method is an easy and reliable method of determining arecoline concentrations in saliva. Sensitivity, specificity, precision, accuracy and reproducibility of the method were demonstrated to be satisfactory for measuring the arecoline level.     

Quality assessment of crude and processed Arecae semen based on colorimeter and HPLC combined with chemometrics methods

Raw Arecae Semen, the seed of Areca catechu L., as well as Arecae Semen Tostum and Arecae semen carbonisata are traditionally processed by stir‐baking for subsequent use in a variety of clinical applications. These three Arecae semen types, important Chinese herbal drugs, have been used in China and other Asian countries for thousands of years. In this study, the sensory technologies of a colorimeter and sensitive validated high‐performance liquid chromatography with diode array detection were employed to discriminate raw Arecae semen and its processed drugs. The color parameters of the samples were determined by a colorimeter instrument CR‐410. Moreover, the fingerprints of the four alkaloids of arecaidine, guvacine, arecoline and guvacoline were surveyed by high‐performance liquid chromatography. Subsequently, Student's t test, the analysis of variance, fingerprint similarity analysis, hierarchical cluster analysis, principal component analysis, factor analysis and Pearson's correlation test were performed for final data analysis. The results obtained demonstrated a significant color change characteristic for components in raw Arecae semen and its processed drugs. Crude and processed Arecae semen could be determined based on colorimetry and high‐performance liquid chromatography with a diode array detector coupled with chemometrics methods for a comprehensive quality evaluation.     

An automatic reaction control chemical ionization technique in ion trap detector for quantitative plasma profding of arecoline in treated alzheimer patients

An automatic reaction control chemical ionization technique in an ion trap detector (lTD) was used to quantitate the levels of the cholinergic drug, arecoline, in plasma of treated patients with Alzheimer’s disease. The chemical ionization reaction was carried out with acetonitrile. The protonated molecules of arecoline (m I z 156) and the internal standard, homoarecoline (m / z 170), were monitored. Human plasma samples were extracted with a readily evaporable solvent mixture, the residues reconstituted and injected along with a tertiary amine-carrier into a capillary gas chromatograph interfaced with the ITD. Standard curves for plasma-extracted arecoline between 20-ng/mL and 156-pg/mL levels were linear (r> 0.9980). Satisfactory precision (relative standard deviation < 20%) and accuracy (relative error < 15%) at the limit of quantitation, 156 pg/mL arecoline, were achieved. Optimal conditions for handling of blood samples obtained by venipuncture were determined. The assay was successfully applied for the therapeutic monitoring of Alzheimer patients treated intravenously with arecoline.     

An ionic liquid coating for determination of sildenafil and UK-103,320 in human serum by capillary zone electrophoresis-ion trap mass spectrometry

Ionic liquid (IL) was covalently bonded onto the silica capillary surface and the electroosmotic flow was reversed over a pH range of 3.5 to 7. Sildenafil (SL) and its metabolite UK-103,320 (UK) in human serum were detected by solid-phase extraction followed by capillary zone electrophoresis-mass spectrometry analysis. The running buffer contained 10 mM acetic acid adjusted to pH 4.5 with 1 M ammonia, and the separating voltage was set to -25 kV. The adsorption of the analytes onto the bare capillary wall was eliminated by the IL coating and the drugs were baseline-separated within 14 min with detection limits (S/N = 3) of 14 and 17 ng/mL for SL and UK, respectively. The method developed showed good intraday precision in terms of relative standard deviation (RSD) with respect to migration time (RSD 相似文献   

Determination of vitamin C and preservatives in beverages by conventional capillary electrophoresis and microchip electrophoresis with capacitively coupled contactless conductivity detection

The separation and detection of commonly used preservatives (benzoate, sorbate) and vitamin C by both conventional CE and microchip electrophoresis with capacitively coupled contactless conductivity detection is presented. The separation was optimized by adjusting the pH-value of the buffer and the use of hydroxypropyl-beta-CD (HP-beta-CD) and CTAB as additives. For conventional CE, optimal separation conditions were achieved in a histidine/tartrate buffer at pH 6.5, containing 0.025% HP-beta-CD and 0.1 mM CTAB. LOD ranged from 0.5 to 3 mg/L (S/N = 3) and the RSDs for migration time and peak area were less than 0.1 and 2%, respectively. A considerable reduction of analysis time can be accomplished by using microchip electrophoresis without significant loss in sensitivity under optimal separation conditions. A histidine/tartrate buffer at pH 6.5, incorporating 0.06% HP-beta-CD and 0.25 mM CTAB, gave detection limits ranging between 3 and 10 mg/L and satisfactory reproducibilities of < or =0.4% for the migration time and < or =3.5% for the peak area. The methods developed are useful for the quantitative determination of food additives in real samples such as soft drinks and vitamin C tablets.     

Determination of Fatty Acid Methyl Esters in Biodiesel Produced from Yellow Horn Oil by LC

A simple and accurate HPLC method with refractive index detection was developed to determine the main fatty acid methyl esters in biodiesel produced from yellow horn oil. Methyl linoleate, methyl linolenate, methyl arachidate, methyl stearate, methyl palmitate and methyl oleate were separated on a HIQ SIL C18W column using methanol as mobile phase. The method has good repeatability and precision, the intraday and interday RSD for both retention time and peak area was less than 3.2%. The LOD (S/N = 3) and LOQ (S/N = 9) were less than 0.004 and 0.015 mg mL⁻¹, respectively.     

Fingerprint analysis of Ligusticum chuanxiong using hydrophilic interaction chromatography and reversed-phase liquid chromatography

Fingerprint analysis is considered one of the most powerful approaches to quality control in traditional Chinese medicines (TCMs). In this study, a binary chromatographic fingerprint analysis was developed using hydrophilic interaction chromatography (HILIC) and reversed-phase liquid chromatography (RPLC) to gain more chemical information about polar compounds and weakly polar compounds. This method was used to construct a chromatographic fingerprint of Ligusticum chuanxiong. The two chromatographic methods demonstrated good precision, reproducibility, and stability, with relative standard deviations of <2% for retention time and 7% for peak area for both HILIC and RPLC separations. Data from the analysis of 14 samples by HILIC and RPLC were processed with similarity analysis, with correlation coefficients and congruence coefficients. This binary fingerprint analysis, using two chromatographic modes, is a powerful tool for characterizing the quality of samples, and can be used for the comprehensive quality control of TCMs.     

Optimization of the separation of a group of antifungals by capillary zone electrophoresis

Two simple, rapid, and efficient methods for the analysis of seven antifungal compounds have been developed by capillary zone electrophoresis. Resolutions higher than 1.5 were obtained using 0.025 M phosphate buffer (pH 2.30) (analysis time close to 9 min) or 0.2 M formic acid (pH 2.15) (analysis time close to 6 min), with an applied voltage of 20 kV and a temperature of 30 degrees C. The highest sensitivity and selectivity can be obtained using phosphate buffer but the shortest analysis times are achieved in the formic system. The analytical characteristics of the optimized methods were investigated. The reproducibility obtained for migration times (RSD(n = 10) < or = 1.0%) and peak areas (RSD(n = 10) < or = 4.3%) was acceptable, but better reproducibilities were obtained when verapamil was used as internal standard (RSD(n = 10) < 0.4% for relative migration times and RSD(n = 10) < or = 2.2% for peak area ratios). The lowest limit of detection was obtained for clotrimazole (0.12 microg/ml) and the highest for fluconazole and voriconazole (0.90 microg/ml). The lowest and the highest limits of quantitation were, respectively, 0.40 microg/ml for clotrimazole and 3.00 microg/ml for fluconazole and voriconazole.     

Application of extraction disks in dissolution tests of clenbuterol and levothyroxine tablets by capillary electrophoresis

Sample preparation procedures using octadecyl (C₁₈) extraction disks were developed to obtain accurate and reproducible results for determinations of clenbuterol (20 μg per dose) and levothyroxine (100 μg per dose) in dissolution media of solid oral dosage forms. Preconcentration of samples allowed final concentrations of 1.1 μg/ml of clenbuterol and 4.0 μg/ml of levothyroxine to be reached prior to CE analysis. The results obtained by CE were in good agreement with those of HPLC. The precision of the migration time, peak area, peak height and accuracy were determined in both intea-day (n = 6) and inter-day (n =18) assays. Linearity was demonstrated over the ranges 0.5–80.0 μg/ml of clenbuterol and 1.0–30.0 μg/ml of levothyroxine. The mean recoveries were higher than 94.0%, ranging from 50 to 125% levels with respect to dose potencies. The proposed methodology may be generally applied to determine drugs at ng/ml concentrations.