Capillary electrochromatographic analysis of barbiturates in serum

A capillary electrochromatographic method was developed for the separation of barbiturates. The separation was optimized in a 75 microm ID capillary, packed with 3-(1,8-naphthalimido)propyl-modified silyl silica gel (NAIP), studying the effect of buffer pH, buffer concentration, and mobile phase composition. Using an applied voltage of 20 kV and the short-end injection method (9 cm capillary effective length), the mobile phase of 1.0 mM citrate buffer (pH 5.0) containing 40% methanol provided the baseline separation of barbital, phenobarbital, secobarbital, and thiopental (internal standard) in less than 4.5 min. The method was successfully applied to the analysis of barbiturates in human serum. Under the optimal conditions, good repeatability and linearity were obtained in the range of 2.90-43.29 microg/mL for barbital, phenobarbital, and secobarbital.     

Application of Central Composite Design for the Determination of Exfoliating Agents in Cosmetics by Capillary Electrophoresis with Electroosmotic Flow Modulation

Multivariate analysis within central composite design is applied to simplify an optimization procedure and explore the interactions among experimental parameters in analytical chemistry. In this study, central composite design was used to identify the optimal capillary electrophoresis conditions with electroosmotic flow modulation to determine seven exfoliating agents in cosmetics. The influence of phosphate concentration, cetyltrimethylammonium bromide concentration, and methanol percentage on the response was evaluated by the use of the chromatographic exponential function to simultaneously investigate the resolution and separation under sixteen sets of capillary electrophoresis conditions. The optimized conditions were 150 mM phosphate solution (pH = 7) containing 0.5 mM cetyltrimethylammonium bromide, 3 mM γ-cyclodextrin, and 25% methanol as the running buffer. To shorten the analysis time, an electroosmotic flow modulating agent (cetyltrimethylammonium bromide) was added to the separation buffer. Calibration plots were linear (r ≧ 0.998) with high precision and accuracy in the homemade cosmetic matrix. The exfoliating agents in two commercial cosmetic products were determined using the optimized conditions, and the results correlated well with results obtained by high-performance liquid chromatography–mass spectrometry.     

Cyclodextrin-Modified Gold Nanoparticle Capillary Electrochromatography with Online Sample Stacking for Simultaneous and Sensitive Determination of Aminobenzoic Acid Isomers

A newly-developed method of complete separation and sensitive determination of o-, m-, and p-aminobenzoic acid isomers was achieved by combining open-tubular columns for capillary electrochromatography (OT-CEC) and online sample stacking. In this study, spherical gold nanoparticles were modified by a covalent attachment of mono-6-thio-β-cyclodextrin, and OT-CEC was formed by immobilizing cyclodextrin-modified gold nanoparticles (CD-AuNP) on prederivatized 3-mercaptopropyl-trimethoxysilane fused-silica capillaries. Based on the theory of moving chemical reaction boundary, effects of several important factors such as the pH and concentration of running buffer and the conditions of stacking analytes were optimized. The optimized separations were carried out in 58 mmol/L HAc buffer at pH 3.0 using a capillary coated with CD-AuNP, while the optimized concentration was carried out in 50 mmol/L disodium hydrogen phosphate (pH 9.5). The linear ranges for m-, p-, and o-aminobenzoic acid were from 5.0 × 10^?4–0.1, 5.0 × 10^?4–0.1 and 1.0 × 10^?4–0.1 mmol/L, respectively. And the detection limits (S/N = 3) were as low as 8.22 × 10^?5, 8.21 × 10^?5, and 3.76 × 10^?5 mmol/L for m-, p-, and o-aminobenzoic acid, respectively. The run-to-run, day-to-day, and column-to-column reproducibilities of migration time were satisfactory with relative standard deviation values of less than 4.5 % in all cases. This method was successfully used in determining procaine hydrochloride injection sample with recoveries in the range of 96.1–106.6 % and relative standard deviations less than 5.0 %.     

Analysis of anabolic androgenic steroids in urine by full-capillary sample injection combined with a sweeping CE stacking method

This study describes an on-line stacking CE approach by sweeping with whole capillary sample filling for analyzing five anabolic androgenic steroids in urine samples. The five anabolic steroids for detection were androstenedione, testosterone, epitestosterone, boldenone, and clostebol. Anabolic androgenic steroids are abused in sport doping because they can promote muscle growth. Therefore, a sensitive detection method is imperatively required for monitoring the urine samples of athletes. In this research, an interesting and reliable stacking capillary electrophoresis method was established for analysis of anabolic steroids in urine. After liquid–liquid extraction by n-hexane, the supernatant was dried and reconstituted with 30 mM phosphate buffer (pH 5.00) and loaded into the capillary by hydrodynamic injection (10 psi, 99.9 s). The stacking and separation were simultaneously accomplished at ?20 kV in phosphate buffer (30 mM, pH 5.0) containing 100 mM sodium dodecyl sulfate and 40 % methanol. During the method validation, calibration curves were linear (r?≥?0.990) over a range of 50–1,000 ng/mL for the five analytes. In the evaluation of precision and accuracy for this method, the absolute values of the RSD and the RE in the intra-day (n?=?3) and inter-day (n?=?5) analyses were all less than 6.6 %. The limit of detection for the five analytes was 30 ng/mL (S/N?=?5, sampling 99.9 s at 10 psi). Compared with simple MECK, this stacking method possessed a 108- to 175-fold increase in sensitivity. This simple and sensitive stacking method could be used as a powerful tool for monitoring the illegal use of doping.     

Capillary Electrophoresis Method for the Chiral Purity Determination of Pregabalin Derivatized with Dansyl Chloride

A capillary electrophoresis method for the determination of the chiral purity of pregabalin upon derivatization with dansyl chloride was developed using design of experiment methodologies. A D-optimal design was used for the identification of the critical process parameters, while a central composite face centered design and Monte Carlo simulations were employed for defining the design space of the method. Final working conditions consisted of a background electrolyte composed of a 100 mM sodium phosphate buffer, pH 2.5, containing 40 mg mL^?1 heptakis(2,3,6-tri-O-methyl)-β-cyclodextrin, a separation voltage of 15 kV and a capillary temperature of 25 °C. The analyses were carried out in a 40/50.2 cm fused-silica capillary with an inner diameter of 50 µm. Upon testing the robustness using a Plackett–Burman design, the method was validated according to the International Council on Harmonization guideline Q2(R1). The method allowed the detection of the (R)-enantiomer at the 0.015% level with a limit of quantitation at the 0.05% level with regard to a sample containing 1.59 mg mL^?1 pregabalin. The method was subsequently applied to the determination of the stereochemical purity of the drug in commercial capsules.     

Determination of Rosuvastatin in Pharmaceutical Formulations by Capillary Zone Electrophoresis

A capillary zone electrophoretic method with diode array detection was developed and validated for the determination of rosuvastatin calcium in pharmaceutical formulations. Using fused-silica capillary (i.d. 50.0 μm, total length 48.5 cm and effective length 40.0 cm), the influence of the buffer composition, buffer pH and buffer concentration, as well as organic modifier, applied voltage, capillary temperature and injection time were investigated to optimize the method. Optimum results were obtained with 50.0 mM borate buffer at pH 9.5, capillary temperature 30 °C and applied voltage 25 kV. The samples were injected hydrodynamically for 5 s at 50 mbar. Detection wavelength was set at 243 nm. Diflunisal was used as internal standard. The migration times of rosuvastatin calcium and diflunisal were 3.20 ± 0.01 and 4.20 ± 0.02. The total time of analysis was <6 min. The method was validated for rosuvastatin calcium determination in pharmaceutical formulations through following performance parameters: stability, linearity, sensitivity, precision, accuracy, recovery, selectivity, robustness and ruggedness. The linear calibration range was 3.00–200.00 μg mL^?1 and the limits of detection and quantification were 1.00 and 3.00 μg mL^?1 with RSD of 4.38 and 3.09%. The proposed method was applied for the determination of rosuvastatin calcium in its pharmaceutical formulation.     

Separation of 5-Lipoxygenase Metabolites Using Cyclodextrin-Modified Microemulsion Electrokinetic Chromatography and Head Column Field-Amplified Sample Stacking

A cyclodextrin-modified microemulsion electrokinetic chromatography method employing head column field-amplified sample stacking was developed for the analysis of arachidonic acid metabolites of the lipoxygenase pathways. The influence of the concentration of boric acid, the surfactant sodium dodecyl sulfate, the co-surfactant 1-butanol and the oil phase octane as well as the pH of the background electrolyte, the separation voltage and the separation temperature was studied. The optimized microemulsion consisting of 20 mM boric acid buffer, pH 9.0, 3.0 % (m/v) sodium dodecyl sulfate, 0.5 % (v/v) octane, 5.0 % (v/v) 1-butanol and 15 mM α-cyclodextrin enabled the separation of 20-hydroxy-leukotriene B₄, leukotriene B₄, 6-trans-leukotriene B₄, 6-trans-12-epi-leukotriene B₄, 5(S)-hydroxy-6-trans-8,11,14-cis-eicosatetraenoic acid, 12(S)-hydroxy-5,8,14-cis-10-trans-eicosatetraenoic acid, 15(S)-hydroxy-5,8,11-cis-13-trans-eicosatetraenoic acid as well as the internal standard prostaglandin B₁ in <10 min employing a separation voltage of 17.5 kV at a temperature of 23 °C. A matrix peak from solid-phase extraction sample workup co-migrated with 5(S)-hydroxy-6-trans-8,11,14-cis-eicosatetraenoic acid affecting peak integration. The addition of 5 % (v/v) 2-propanol to the microemulsion resulted in the separation of this eicosatetraenoic acid and the matrix components at the expense of analysis time and peak resolution between the diastereomers 6-trans-leukotriene B₄ and 6-trans-12-epi-leukotriene B₄. In summary, the MEEKC method appeared to be especially suitable for the more polar arachidonic acid metabolites.     

Separation of plant hormones from biofertilizer by capillary electrophoresis using a capillary coated dynamically with polycationic polymers.

A new, simple and rapid capillary electrophoresis (CE) method, using hexadimethrine bromide (HDB) as electroosmotic flow (EOF) modifier, was developed for the identification and quantitative determination of four plant hormones, including gibberellin A3 (GA3), indole-3-acetic acid (IAA), alpha-naphthaleneacetic acid (NAA) and 4-chlorophenoxyacetic acid (4-CA). The optimum separation was achieved with 20 mM borate buffer at pH 10.00 containing 0.005% (w/v) of HDB. The applied voltage was -25 kV and the capillary temperature was kept constant at 25 degrees C. Salicylic acid was used as internal standard for quantification. The calibration dependencies exhibited good linearity within the ratios of the concentrations of standard samples and internal standard and the ratios of the peak areas of samples and internal standard. The correlation coefficients were from 0.9952 to 0.9997. The relative standard deviations of migration times and peak areas were < 1.93 and 6.84%, respectively. The effects of buffer pH, the concentration of HDB and the voltage on the resolution were studied systematically. By this method, the contents of plant hormone in biofertilizer were successfully determined within 7 min, with satisfactory repeatability and recovery.     

Determination of gallic acid and salidroside in Rhodiola and its preparation by capillary electrophoresis

A new, simple, and rapid capillary electrophoresis (CE) method employing hexadimethrine bromide (HDB) as electroosmotic flow (EOF) modifier was developed for the identification and quantitative determination of two pharmaceutically active constituents—gallic acid (GA) and salidroside (S)—in extracts of Rhodiola root and its medicinal preparation. The optimum separation was achieved at pH 11.00 with the use of 10 mM borate buffer containing 0.001% (w/v) of HDB. The applied voltage was ∼15 kV and the capillary temperature was kept constant at 25°C. m-Phthalic acid was used as an internal standard for quantification. The calibration dependences exhibited good linearity for the ratios of the concentrations of standard samples and internal standard and the ratios of the peak area of samples and internal standard over the concentration range from 24 to 1200 μg/mL for GA and 2.4 to 72 μg/mL for S. The correlation coefficients were 0.9999 and 0.9997, and the detection limits of the CE method corresponding to a signal-to-noise ratio of three were 6 and 2 μg/mL for GA and S, respectively. The relative standard deviations of the relative migration time and the relative peak area of samples were 0.5 and 4.0% for GA and 1.9 and 5.3% for S. The effects of buffer pH and the concentration of HDB on the resolution were studied systematically. The contents of these two active compounds in Rhodiola root and its preparation were successfully determined over 6 min with satisfactory repeatability and recovery. The text was submitted by the authors in English.     

Enantioselective determination of modafinil in pharmaceutical formulations by capillary electrophoresis, and computational calculation of their inclusion complexes

A fast capillary electrophoretic method is described for the separation and determination of the enantiomers of the novel wake-promoting agent, modafinil. Several parameters affecting the separation were studied, including the type and concentration of chiral selector, buffer pH, buffer concentration, voltage and temperature. Good chiral separation of the racemic mixture was achieved in less than 5 min with resolution factor Rs?=?2.51, using a bare fused-silica capillary and a background electrolyte (BGE) of 25 mM H₃PO₄?1 M tris solution; pH 8.0; containing 30 mg mL^?1 of sulfated-β-cyclodextrin (S-β-CD). The separation was carried out in normal polarity mode at 25 ^?C, 18 kV and using hydrostatic injection. Acceptable validation criteria for selectivity, linearity, precision, and accuracy were included. The developed method was successfully applied to the assay of enantiomers of modafinil in pharmaceutical formulations. The computational calculations for the enantiomeric inclusion complexes rationalized the reasons for the different migration times between the modafinil enantiomers.     

Determination of Phenolic Glucosides in Gentiana piasezkii by Capillary Zone Electrophoresis

A capillary zone electrophoretic method has been developed for the quantitative analysis of five phenolic glucosides, 6′-O-vanilloylarbutin (VA), 7-O-feruloylorientin (FE), lutonarin (LN), isoorient (IO) and luteolin (LL), in Gentiana piasezkii with UV detection at 270 nm. 7-O-β-D-glucosyl-coumarin was selected as the internal standard. The applied voltage was 15 kV and the capillary temperature was kept constant at 25 °C. The effect of pH, the concentration of methanol and boric acid on migration were studied systematically. Optimum separation was achieved with 200 mM boric acid buffer at pH 9.50 containing 10% (v/v) methanol. Regression equations revealed good linear relationship between the peak area ratio of each compound and internal standard and its concentration. The correlation coefficients were 0.9975, 0.9997, 0.9998, 0.9998 and 0.9988 for VA, FE, LN, IO and LL, respectively. The relative standard deviations of migration time and the peak area ratio of each analyte and internal standard were <1.78% and 4.93%, respectively. The contents of the five compounds in Gentiana piasezkii were successfully determined with satisfactory repeatability and recovery.     

Optimization and Parameter Study for Chiral Separation by Capillary Electrophoresis

Orthogonal design and uniform design were used for the optimization of separation of enantiomers using 2,6-di-O-methyl-β-cyclodextrin (DM-β-CD) as a chiral selector by capillary zone electrophoresis. The concentration of DM-β-CD, buffer pH, running voltage, and capillary temperature were selected as variable parameters, their different effects on peak resolution were studied by the design methods. It was concluded that orthogonal design offers a rapid and efficient means for testing the importance of individual parameters and for determining the optimum operating conditions. However, for a large number of both factors and levels, uniform design is more efficient. The effect of addition of methanol and citric acid buffer on the separation of enantiomers was also examined.     

Cyclodextrin-Modified Gold Nanoparticle Capillary Electrochromatography with Online Sample Stacking for Simultaneous and Sensitive Determination of Aminobenzoic Acid Isomers

A newly-developed method of complete separation and sensitive determination of o-, m-, and p-aminobenzoic acid isomers was achieved by combining open-tubular columns for capillary electrochromatography (OT-CEC) and online sample stacking. In this study, spherical gold nanoparticles were modified by a covalent attachment of mono-6-thio-β-cyclodextrin, and OT-CEC was formed by immobilizing cyclodextrin-modified gold nanoparticles (CD-AuNP) on prederivatized 3-mercaptopropyl-trimethoxysilane fused-silica capillaries. Based on the theory of moving chemical reaction boundary, effects of several important factors such as the pH and concentration of running buffer and the conditions of stacking analytes were optimized. The optimized separations were carried out in 58 mmol/L HAc buffer at pH 3.0 using a capillary coated with CD-AuNP, while the optimized concentration was carried out in 50 mmol/L disodium hydrogen phosphate (pH 9.5). The linear ranges for m-, p-, and o-aminobenzoic acid were from 5.0 × 10⁻⁴–0.1, 5.0 × 10⁻⁴–0.1 and 1.0 × 10⁻⁴–0.1 mmol/L, respectively. And the detection limits (S/N = 3) were as low as 8.22 × 10⁻⁵, 8.21 × 10⁻⁵, and 3.76 × 10⁻⁵ mmol/L for m-, p-, and o-aminobenzoic acid, respectively. The run-to-run, day-to-day, and column-to-column reproducibilities of migration time were satisfactory with relative standard deviation values of less than 4.5 % in all cases. This method was successfully used in determining procaine hydrochloride injection sample with recoveries in the range of 96.1–106.6 % and relative standard deviations less than 5.0 %.

     

Rapid separation of barbiturates and benzodiazepines by capillary electrochromatography with 3-(1,8-naphthalimido)propyl-modified silyl silica gel

A capillary electrochromatographic (CEC) method was applied to the simultaneous separation of barbiturates (barbital, phenobarbital, secobarbital and thiopental) and benzodiazepines (nitrazepam, diazepam and triazolam). The separation was performed in a 75 microm i.d. capillary, packed with 3-(1,8-naphthalimido)propyl-modified silyl silica gel (NAIP), studying the effects of buffer pH and mobile phase composition. Using an applied voltage of 20 kV and the short-end injection method (9 cm capillary effective length), the mobile phase of 1.0 mM citrate buffer (pH 5.0) containing 45% methanol provided the baseline separation of seven toxic drugs in less than 9 min. In CEC with NAIP, the benzodiazepines were separated by the combination of hydrophobic and pi-pi interactions, whereas the separation of the barbiturates was based on the hydrophobic interaction.     

Rapid Determination of Coumarins in Plants by Capillary Electrophoresis

The goal of this study was to optimize the parameters for capillary electrophoresis to separate and determine aesculin, aesculetin, umbelliferone, and dihydrocoumarin in plant materials. A simple and rapid capillary zone electrophoresis method is reported for this separation that required less than nine minutes. A bare fused silica capillary was employed using 20 mM borax in 5% methanol at pH 10.1 as the background electrolyte with an applied voltage of 30 kV at 27°C. Good linearity and reproducibility were obtained with high correlation coefficients. The analytes were determined by molecular absorption at 194 and 206 nm. Coumarins were determined in Aesculus hippocastanum L., Cichorium intybus L., Melilotus officinalis L., and Juniperus communis L. “Pendula.” The concentrations of aesculin and aesculetin were 3.07 and 6.31 mg g^?1 in Aesculus hippocastanum. In Cichorium intybus, the aesculetin concentration was 2.42 mg g^?1. The dihydrocoumarin concentration was 0.54 mg g^?1 in Melilotus officinalis, and the concentration of umbelliferone was 0.58 mg g^?1 in Juniperus communis “Pendula.”     

毛细管电泳-激光诱导荧光用于中药制剂中氨基酸成分的分析

建立了一种用于测定中药制剂中氨基酸成分的毛细管电泳-荧光检测方法. 用含有α-环糊精(α-CD)的硼砂缓冲溶液为背景电解质, 经异硫氰酸荧光素(FITC)衍生的5种氨基酸在50 min内可以得到很好的分离和测定. 考查了各个分离参数对分离的影响, 得到的优化条件为: 含45 mmol/L的α-环糊精的80 mmol/L硼砂缓冲溶液(pH值9.2)作为背景电解质, 分离电压20 kV; 柱温22 ℃. 衍生试剂FITC与单个氨基酸的化学计量比为4∶1时, 能够获得稳定荧光强度的氨基酸衍生物. 在优化条件下, 各氨基酸成分在73.5～2900 nmol/L 的浓度范围内呈良好的线性关系(相关系数r2为0.9906～0.9998). 保留时间和峰面积的相对标准偏差分别为0.8%～3.0%和0.7%～5.7%, 检测限(3倍信噪比)为3.5～35 nmol/L. 该方法准确可靠, 可用于质量控制为目的的中药制剂中氨基酸成分的定量测定.     

Determination of Inorganic Anions by Capillary IC Using Hexadimethrine Bromide-Modified Silica Stationary Phases

A simple, rapid and highly sensitive capillary ion chromatographic method for direct determination of iodide and thiocyanate is reported. Separation was achieved on a laboratory-made capillary column (100 mm × 0.32 mm i.d.) packed with silica gel, followed by modification with 20 mM hexadimethrine bromide. Sodium perchlorate?Cmethanol (95:5, v/v) was used as the eluent and analyte anions were detected at 225 nm. Iodate, bromate, nitrate, iodide and thiocyanate were eluted within 8 min, with relative standard deviations of the retention time, peak area and peak height smaller than 2.4%. Effects of the eluent composition on the retention behavior were also investigated. The limit of detection (S/N = 3) of iodide was 6.5 ??g L^?1, whereas that of thiocyanate was 16.2 ??g L^?1. The method was successfully applied to the rapid and direct determination of iodide in powdered milk and thiocyanate in human saliva without any pre-concentration. The modified column could be used for about 1 month (8 h operation per day) without loss of hexadimethrine bromide.     

CE, with Hydroxypropyl-β-Cyclodextrin as Chiral Selector, for Separation and Determination of the Enantiomers of Amlodipine in the Serum of Hypertension Patients

A capillary electrophoretic method for separation of the enantiomers of amlodipine in the serum of hypertension patients has been established and validated. The two enantiomers were separated in a fused-silica capillary with phosphate running buffer (75 mmol L^?1, pH 2.5) containing 15 mmol L^?1 hydroxypropyl-β-cyclodextrin (HP-β-CD). The effects on the separation of buffer pH and concentration, separation potential, and concentration of HP-β-CD were investigated. The range of quantitation for both enantiomers was 2.0–16.0 μg mL^?1. Intra-day and inter-day relative standard deviation (RSD; n = 5) was <10%. The limits of detection (LOD) and quantification (LOQ) of the amlodipine enantiomers, at 214 nm, were approximately 0.5 and 0.7 μg mL^?1, respectively (S/N = 3 and 10, respectively; 5-s injection). Recovery was always >85%. Results from enantiomer separation and quantification showed that concentrations of the enantiomers of amlodipine in serum from an elderly patient were higher than in serum from a young patient administered the same dose. The method was useful for determining the concentration of the enantiomers of amlodipine in hypertension patient serum and for monitoring the transition behavior of the enantiomers in humans. The method proved suitable for application to the separation of the enantiomers of amlodipine and analysis of clinical samples.     

Determination of Betamethasone and Dexamethasone in Human Urine and Serum by MEKC After an Experimental Design

A simple and reliable micellar electrokinetic capillary chromatography method has been presented for the simultaneous determination of betamethasone (BM) and its epimer dexamethasone (DM) in human urine and serum. A three level full factorial experimental design was employed to search for the optimum conditions. Rapid and baseline separation of BM and DM was obtained within 7 min with the optimum conditions of 30 mM borax buffer, 30 mM sodium dodecyl sulfate at pH 10.0, separation voltage at 18 kV, injection time 15 s at a height of 10 cm, using sodium sorbate as internal standard. The proposed method was validated with respect to stability, precision, linearity and accuracy. Good relationship between peak area ratio and analyte concentration was linear over 30–1,000 µg mL^?1 for BM and DM with correlation coefficients ≥0.9993. Relative standard deviations of the method were all less than 4.50% in the intra-day and inter-day analysis. The developed method was applied to assay spiked human urine and serum samples containing both compounds with recoveries in the range of 97.5–100.5%.     

Optimization and Validation of a Capillary MEKC Method for Determination of Proteins in Urine

Proteinuria, i.e. increased excretion of proteins in urine, is a common sign indicating renal or urinary tract diseases. In this study, a fast and simple procedure for urine sample preparation and capillary micellar electrokinetic chromatographic analysis is presented, without any sample pretreatment prior to the analysis. The developed MEKC method was employed for simultaneous determination of albumin (ALB), haemoglobin (HGB), and myoglobin (MYO) in human urine samples obtained from patients with diagnosed proteinuria. Optimum conditions for detection and separation of ALB, HGB, and MYO are 50 mmol L⁻¹ borate buffer containing 20 mmol L⁻¹ SDS (pH 9.3), injection 40 mbar × 20 s, voltage 25 kV, temperature 30 °C, and detection wavelength 200 nm. The method was shown to be specific, accurate, linear (correlation coefficients r ² > 0.99), and precise (RSD below 3.75 and 7.23% for migration time and peak area, respectively). Multi-variable-at-a-time (MVAT) approach for robustness testing shows no significant variations in accuracy, specificity, and precision as RSD values were lower than 5 and 10% for migration time and peak area, respectively. The presented method is applicable for routine analyses of urine samples as a screening method for patients with excess ALB, HGB, and MYO.