Monitoring diclofenac sodium in single human erythrocytes introduced by electroporation using capillary zone electrophoresis with electrochemical detection.

A method for determination of the drug diclofenac sodium introduced into individual human erythrocytes by electroporation using capillary zone electrophoresis with electrochemical detection at a carbon fiber array microelectrode was developed. In this method, the whole cell was injected into the separation capillary by electromigration. Cell lysis was accomplished by injecting a plug of the separation buffer (1.25 x 10(-2) mol/L Na2B4O7-3.13 x 10(-3) mol/L NaOH). The optimum conditions of separation and detection were 20 kV for the separation voltage and 1.0 V for the detection potential. The concentration of diclofenac sodium in the single cells was quantified by a calibration curve. The mean concentration of diclofenac sodium introduced into the cell was 4.21 micromol/L. The relative standard deviation of the concentration of diclofenac sodium introduced into ten cells is 10%.     

Determination of diclofenac sodium by capillary zone electrophoresis with electrochemical detection

Capillary zone electrophoresis was employed for the determination of diclofenac sodium using an end-column amperometric detection with a carbon fiber microelectrode, at a constant potential of 0.83 V vs. saturated calomel electrode. The optimum conditions of separation and detection are 4.90 x 10(-3) mol/l Na2HPO4-3.10 x 10(-3) mol/l NaH2PO4 (pH 7.0) for the buffer solution, 10 kV for the separation voltage, 5 kV and 10 s for the injection voltage and the injection time, respectively. The limit of detection is 2.5 x 10(-6) mol/l or 5.2 fmol (S/N=2). The relative standard deviation is 0.8% for the migration time and 4.7% for the electrophoretic peak current. The method was applied to the determination of diclofenac sodium in human urine.     

Simultaneous determination of N,N-dimethylaniline and phenol in wastewater by high-performance liquid chromatography with chemiluminescence detection.

A method using HPLC-CL linkage was developed for simultaneous determination of N,N-dimethylaniline and phenol in wastewater, based on the strong sensitive chemiluminescence of the luminol-K3Fe(CN)6 systems in alkaline medium. The separation was carried out on a Hypersil ODS column with a mobile phase of ethanol-0.01% triethylamine (2:1, v/v). The linear ranges for N,N-dimethylaniline determinations were 2.0 x 10(-7) - 2.5 x 10(-5) g/mL and 4.0 x 10(-5) - 1.5 x 10(-4) g/mL with a detection limit (3sigma) of 1.20 x 10(-8) g/mL; the relative standard deviation (3sigma) for 5.0 x 10(-6) g/mL N,N-dimethylaniline was 1.4% (n = 6). The range for phenol was from 5.1 x 10(-7) to 1.3 x 10(-4) g/mL, and a detection limit (3sigma) of 2.5 x 10(-8) g/mL could be obtained. The method can be useful for the determination of N,N-dimethylaniline and phenol in some environmental samples.     

HPLC method for determination of diclofenac in human plasma and its application to a pharmacokinetic study in Turkey

A simple high-performance liquid chromatography (HPLC) method has been developed for determination of diclofenac in human plasma. The method was validated on Ace C(18) column using UV detection. The mobile phase consisted of 20 mM phosphate buffer (pH 7) containing 0.1% trifluoroacetic acid-acetonitrile (65:35, v/v). Calibration curve was linear between the concentration range of 75-4000 ng/mL. Intra- and inter-day precision values for diclofenac in plasma were less than 3.6, and accuracy (relative error) was better than 5.3%. The limits of detection and quantification of diclofenac were 25 and 75 ng/mL, respectively. Also, this assay was applied to determine the pharmacokinetic parameters of diclofenac in healthy Turkish volunteers who had been given 50 mg diclofenac.     

Development and validation of stability-indicating HPLC method for the simultaneous determination of paracetamol, tizanidine, and diclofenac in pharmaceuticals and human serum

A method is described for the simultaneous determination of paracetamol, tizanidine, and diclofenac in mixtures. The method was based on HPLC separation of the three drugs followed by UV detection at 254 nm. The separation was carried out on a Hypersil ODS, C18 (250 x 4.6 mm id, 10 microm particle size) column using the mobile phase aqueous 0.2% ammonium carbonate-methanol (60 + 40, v/v) at a flow rate of 1 mL/min. The linear regression analysis data were used for the regression curve in the range of 170-10 000 ng/mL for paracetamol, 120-10 000 ng/mL for tizanidine, and 20-10 000 ng/mL for diclofenac. No chromatographic interference from tablet excipients was found. In order to check the selectivity of the proposed method, degradation studies were carried out using hydrolysis (acid, basic, and neutral), thermolysis, and oxidation. The developed method, after being validated in terms of precision, robustness, recovery, LOD, and LOQ, was successively applied to the analysis of pharmaceutical formulations and human serum.     

Study of the separation and determination of monosaccharides in soluble coffee by capillary zone electrophoresis with electrochemical detection

A simple, fast and reliable method, based on capillary electrophoresis with electrochemical detection, for the separation and determination of six monosaccharides, namely glucose, galactose, arabinose, fructose, xylose and ribose, in soluble coffees was developed. A copper disk electrode was used as the working electrode. The optimum conditions for separation and detection were 50 mmol L-1 sodium hydroxide buffer (pH 12.7), separation voltage 5 kV and detection potential 0.65 V (vs. Ag/AgCl). The linear ranges were from 5.0 x 10(-3) to 0.5 mmol L-1 for all six sugars. All regression coefficients were > 0.99. The detection limits for all the sugars were 1.0 x 10(-3) mmol L-1. The RSD of the peak current was < 4.2% (n = 5). The proposed method was applied directly to the separation and determination of the six sugars without prior derivatization, and the assay results were satisfactory.     

High-performance liquid chromatographic determination of acetone in blood and urine in the clinical diagnostic laboratory.

A method for the determination of acetone in plasma or urine by high-performance liquid chromatography (HPLC) was developed. Plasma specimens are deproteinized with acetonitrile (1:1, v/v) 2,4-dinitrophenylhydrazine (DNPH) is added to the supernatant or to filtered urine samples, similarly treated with acetonitrile (2:1, v/v) to prevent crystallization of the synthesized phenylhydrazone. An aliquot (20 microliters) of the reaction mixture was subjected to HPLC at ambient temperature using a reversed-phase Pecosphere 3 x 3 C18 column with acetonitrile-water (45:55, v/v) as eluent at a flow-rate of 1 ml/min and detection at 365 nm. Hydroxyacetone and acetoacetate phenylhydrazone derivatives do not interfere. The identification of acetone by its retention time was confirmed by comparison with a laboratory-synthesized acetone DNPH derivative. The concentration of acetone, eluted within 3 min, was determined by the peak-height method. The detection limit was 0.034 mmol/l; the relative standard deviations were less than 5% within run (n = 20) and less than 10% between run (n = 20).     

Monitoring bronchodilators with direct injection

A procedure was developed for the determination of caffeine and theophylline using a C18 column (5 microm, 250 mm x 4.6 mm) and micellar liquid chromatography using hybrid mobile phases containing sodium dodecyl sulfate (SDS) and propanol, butanol or pentanol as modifiers. Detection was performed with a variable wavelength UV-vis detector at 272 nm. After the application of an interpretative strategy for the selection of the optimimum mobile phase, caffeine and theophylline can be resolved and determined in serum samples by direct injection, using a mobile phase made up of 50 mM SDS-2.5% (v/v) propanol-10 mM KH2PO4, pH 7, with an analysis time below 5 min. Calibration was linear in the range 0.05 to 50 microg mL(-1) with r > 0.999. The statistical evaluation of the method was examined by performing intra-day (n = 6) and inter-day calibration (n = 7) and was found to be satisfactory, with highly accurate and precise results. The proposed method was suitably validated and applied to the determination of caffeine and theophylline in serum samples of patients treated with bronchodilators.     

Determination of arsenate by sorption pre-concentration on polystyrene beads packed in a microfluidic device with chemiluminescence detection

A highly sensitive chemiluminescence (CL) method for the determination of arsenate in water based on a simple microfluidic device was developed. The method was based on sorption pre-concentration of arsenate as a form of vanadomolybdoarsenate heteropoly acid (VMoAs-HPA) ion-paired with hexadecyltrimethylammonium bromide on the surface of polystyrene beads packed in a microfluidic device monitored by chemiluminescence detection. The composition of the VMoAs-HPA complex was studied by varying the concentrations of ammonium molybdate, ammonium vanadate and sulfuric acid with a variable-size simplex optimization process, of which the optimum concentrations were 6.3 x 10(-5), 5.0 x 10(-6) and 1.0 x 10(-2) M, respectively. In this work, 1.0 x 10(-3) M ethylenediaminetetraacetic acid was added to all work solutions to remove the interferences of the other metal ions on the CL detection. The integration of sorption pre-concentration not only increased the detection sensitivity but also eliminated the interference from phosphate and chromate. The calibration plot was linear from 1.0 x 10(-7) to 5.0 x 10(-5) M As(v). The limit of detection was 8.9 x 10(-8) M As(v) (S/N = 3). The time required for one analysis run was as short as 5 min. The relative standard deviation was 5.9% (n = 9). This method was successfully applied to the determination of arsenate in mineral-, drinking- and tap-water samples.     

Molecular imprinting-chemiluminescence determination of trimethoprim using trimethoprim-imprinted polymer as recognition material

A new molecular imprinting-chemiluminescence method for the determination of trimethoprim was developed, in which trimethoprim-imprinted polymer was used as the molecular recognition material and the CL reaction of trimethoprim with potassium permanganate in acidic medium was used as the detection system. The CL intensity responds linearly to the concentration of trimethoprim within the 5.0 x 10(-8)-5.0 x 10(-6) g mL(-1) range (r= 0.9983) with a detection limit of 2 x 10(-8) g mL(-1). The relative standard deviation for the determination of 1.0 x 10(-7) g mL(-1) trimethoprim solutions is 4.8% (n= 9). The method has been applied to the determination of trimethoprim in pharmaceutical preparations and body fluids, and satisfactory results were obtained.     

Separation and determination of norepinephrine, epinephrine and isoprinaline enantiomers by capillary electrophoresis in pharmaceutical formulation and human serum

A capillary electrophoresis method with ultraviolet (UV) detection was developed and optimized for the enantiomer separation of norepinephrine (NE), epinephrine (EP) and isoprenaline (IP) using dual cyclodextrins (CDs) of 2-hydroxypropyl-beta-CD (HP-beta-CD) and heptakis (2,6-di-o-methyl)-beta-CD (DM-beta-CD) as chiral selectors. Optimal separation was obtained using a running buffer of 50mM phosphate containing 30mM HP-beta-CD and 5mM DM-beta-CD at pH 2.90 and a field strength of 20kV in 45cmx75mum (40cm effective length) uncoated capillary. The UV absorbance detection was set at 205nm. A 0.1% (w/w) polyethylene glycol or 0.1% (v/v) acetonitrile was used to enhance the detection sensitivity. There was a wide and excellent linear calibration graph for each enantiomer in the range 1.0x10(-3) to 1.0x10(-6)M and the detection limit (S/N=3) was found from 8.5x10(-7) to 9.5x10(-7)M. The method has been applied for the determination of isoprenaline in isoprenaline hydrochloride aerosol and to the analysis of serum samples. The recoveries of NE and EP in serum and IP in drug were ranged from 90 to 110%. The relative standard deviations of all the analyte peaks were less than 2.8% for migration time and less than 4.8% for peak area.     

胶束电动色谱-激光诱导荧光检测法测定肌松弛药巴氯芬

以4-氯-7-硝基苯并-2-氧杂-1,3-二唑(NBD-Cl)为柱前衍生试剂,建立了胶束电动色谱-激光诱导荧光检测法测定肌松弛药巴氯芬(BAL)的新方法。经过实验条件的优化,采用15 mmol/L硼砂、20 mmol/L十二烷基硫酸钠、10%(v/v)乙腈、pH 9.75的缓冲体系,在分离电压为17.5 kV、柱温为25 ℃的条件下,压力进样3.45 kPa(0.5 psi)×3 s,巴氯芬及其内标物的衍生产物在7 min内实现较好的基线分离,线性范围为0.025～25 mg/L,相关系数为0.9999,检出限(S/N=3)和定量限(S/N=10)分别为0.90 μg/L和6.25 μg/L。该方法被应用于巴氯芬制剂及加入巴氯芬对照品的尿液样品分析,回收率范围分别为101.6%～107.9%和107.0%～109.6%。该方法有望应用于巴氯芬药物制剂的质量监控以及为巴氯芬药物代谢的研究提供辅助手段。     

铜（III）配合物-罗丹明6G体系流动注射化学发光法测定头孢米诺钠

在酸性条件下,头孢米诺钠对铜（III）配合物-硫酸-罗丹明6G化学发光体系有强烈的增敏作用,据此建立了流动注射化学发光法定量分析头孢米诺钠方法。头孢米诺钠浓度在2．0×10^-7-6．0×10^-6g／mL范围内与化学发光强度呈良好的线性关系,相关系数r=0．99969,检出限为1．4×10^-7g／mL。对2．0×10^-7g／mL头孢米诺钠水溶液进行11次平行分析,测定结果的相对标准偏差为1．69％。利用该方法对鸡血样品和头孢米诺钠针剂中头孢米诺钠的含量进行测定,加标回收率为90．2％～102．1％。     

A simple and rapid flow injection chemiluminescence determination of cysteine with Ru(phen)3(2+)-Ce(IV) system

A new chemiluminescence system was developed for the determination of cysteine by flow injection system. This method is based on the reaction of L-cysteine with Ru(phen)3(2+) and Ce(IV) to produce chemiluminescence. The calibration curve was linear over the range 8.0x10(-7) to 4.0x10(-5) and 4.0x10(-5) to 1.0x10(-3) M with a detection limit of 7.0x10(-7) M (S/N=3). The relative standard deviation of 4.0x10(-6) M cysteine was found 3.5% (n=10). The influence of potential interfering substances was studied. The proposed method was successfully applied for the flow injection determination of cysteine in the real samples with minimum sampling rate of 90 sample/h.     

凝胶渗透色谱净化-气相色谱/串联质谱分析蘑菇中的36种农药残留

建立了用凝胶渗透色谱净化-气相色谱/串联质谱分析蘑菇中36种农药残留的方法。蘑菇中的待测农药组分在30 ℃条件下用乙酸乙酯提取,高速匀浆后通过凝胶渗透色谱净化;选用填料为中性多孔的聚苯乙烯二乙烯基苯微球体的S-X3玻璃柱(22 g,19 cm×2 cm)作为凝胶渗透色谱净化柱,流动相为乙酸乙酯-环己烷(体积比为1∶1)溶液,流速5 mL/min;收集第7~15 min流出的液体用气相色谱-三重四极杆串联质谱仪测定。在0.01~1.0 mg/L的质量浓度范围内,各种农药标准溶液的线性相关系数均大于0.99。在样品中添加36种农药(添加水平为0.01,0.05,0.10 mg/kg)的混合标准溶液,平均回收率为72.6%~117.1%,相对标准偏差为2.0%~10.8%(n=5),最低检出限为 0.1~0.7 μg/kg,最低定量限为 0.2~2 μg/kg。     

Extraction and Spectrophotometric Determination of Diclofenac in Pharmaceuticals

A new simple, rapid and sensitive spectrophotometric method has been developed for the determination of diclofenac sodium (Dicl) in pharmaceutical preparations. This method is based on the reaction of diclofenac sodium with an analytical reagent 1,3,3‐trimethyl‐5‐thiocyanato‐2‐[3‐(1′,3′,3′‐trimethyl‐3′‐H‐indol‐2′‐ylidene)‐propenyl]‐indolium cloride (TIC) at pH 8.0‐11.0 and the extraction of ion associate colored complex. Optimal conditions for the complex formation between Dicl and TIC were studied. This ion associate complex (1:1) was detected and extracted with toluene and an absorption maximum at 566.2 nm against a blank reagent. The calibration graph was linear from 0.9‐11.0 μg/mL of diclofenac and the detection limit was 0.86 μg/mL.     

凝胶渗透色谱净化-超高效液相色谱-串联质谱法测定皮革制品中7种尼泊金酯类防腐剂

利用超高效液相色谱-串联质谱(UPLC-MS/MS)结合凝胶渗透色谱(GPC)技术,建立了一种快速分离和测定皮革制品中7种尼泊金酯类防腐剂的分析方法。样品经超声提取、浓缩、GPC净化,甲醇-水溶液(1:1, v/v)溶解,采用Acquity UPLCBEH C18柱(50 mm×2.1 mm, 1.7 μm)分离,以甲醇和水为流动相,梯度洗脱,电喷雾负离子模式电离,采用多反应监测模式检测和外标法定量。该方法在0.1～1.0 mg/L范围内线性关系良好(r＞0.99);在添加量为0.5～3.0 mg/kg时,平均回收率为(79.44±5.67)%～(98.07±9.50)%,相对标准偏差(RSD)为4.24%～14.00%;方法的检出限(LOD)为4～12 μg/kg,定量限(LOQ)为13.2～39.6 μg/kg。该方法操作简便、快捷、灵敏、准确,适合皮革中多种尼泊金酯类防腐剂的确证和定量测定。     

High-performance liquid chromatographic determination of usnic acid in plasma.

A high-performance liquid chromatographic method for the determination of usnic acid in human plasma using diclofenac sodium as internal standard is described. Plasma proteins were precipitated with methanol. A 250 mm x 4 mm I.D. Nucleosil. C18 (5 microns) column with a mobile phase consisting of methanol-phosphate buffer (pH 7.4) (70:30, v/v) was used. Chromatography was performed at ambient temperature with flow-rate of 1 ml min-1 and ultraviolet detection at 280 nm. Each analysis required no longer than 7 min. Quantification was achieved by measurement of the peak-height ratio and the absolute recovery varied from 93.8 to 97.3%. The limit of quantitation of usnic acid in plasma was 0.25 micrograms ml-1. The intra-day relative standard deviation (R.S.D.) ranged from 1.24 to 4.53% and the inter-day R.S.D. from 2.23 to 8.25% at three different concentrations. The method was applied to the determination of plasma levels of usnic acid after intravenous and oral administration to study its disposition in a healthy male rabbit.     

Quantitation of transdermal tadalafil in human skin by reversed-phase high-performance liquid chromatography

A reliable and sensitive HPLC method was developed for the quantitation of tadalafil transdermal permeation through human skin. An RP column with UV detection at 290 nm was used for chromatographic separation at ambient temperature. The mobile phase was acetonitrile-water containing 20 mM pH 7 phosphate buffer (35/65, v/v) with a flow rate of 1.0 mL/min. The LOQ achieved was 1 ng/mL, and the calibration curve showed good linearity over the concentration range of 5-2000 ng/mL for tadalafil, with a determination coefficient (R2) of 0.998. The RSD values of intraday and interday analyses were all within 7%. Parameters of validation proved the precision of the method; this validated method was applied for the determination of tadalafil in transdermal permeation and drug deposition in human skin studies.     

Determination of purine and pyrimidine bases in DNA by micellar electrokinetic capillary chromatography with electrochemical detection

A method based on micellar electrokinetic capillary chromatography with electrochemical detection was developed for the determination of cytosine, 5-methylcytosine (5-MC), thymine, adenine, and guanine in the hydrolysates of DNA. The working electrode was fabricated in a novel self-positioning carbon disc electrode system that can align the capillary outlet with the working electrode without a three-dimensional micromanipulator. The five analytes could be well separated within 10 min in a 40 cm length capillary at a separation voltage of 9 kV in a 40 mmol/l borate buffer (pH 10.0) containing 100 mmol/l sodium dodecyl sulfate. Good linearity was observed between peak current and concentration of bases over three orders of magnitude with the detection limits (SIN=3) ranging from 1.28 x 10(-6) to 5.02 x 10(-6) mol/l. This proposed method demonstrated long-term stability and reproducibility with relative standard deviations of less than 5% for both migration time and peak current (n=7). It has been successfully applied to determine bases including 5-MC in the hydrolysates of fish sperm DNA, calf thymus DNA, and DNA isolated from spleen cells of female mice.