Susheela Rani

Novel micro-extraction by packed sorbent procedure for the liquid chromatographic analysis of antiepileptic drugs in human plasma and urine.

A method for the simultaneous determination of the antiepileptic drugs, phenobarbital (PHB), phenytoin (PTN), carbamazepine (CBZ), primidone (PRM) and oxcarbazepine (OXC) in human plasma and urine samples by using micro-extraction in a packed syringe as the sample preparation method connected with LC/UV (MEPS/LC/UV) is described. Micro-extraction in a packed syringe (MEPS) is a new miniaturized, solid-phase extraction technique that can be connected online to gas or liquid chromatography without any modifications. In MEPS approximately 1 mg of the solid packing material is inserted into a syringe (100-250 μL) as a plug. Sample preparation takes place on the packed bed. The bed can be coated to provide selective and suitable sampling conditions. The new method is very promising, easy to use, fully automated, inexpensive and quick. The standard curves were obtained within the concentration range 1-500 ng/mL in both plasma and urine samples. The results showed high correlation coefficients (R(2) >0.988) for all of the analytes within the calibration range. The extraction recovery was found to be between 88.56 and 99.38%. The limit of quantification was found to be between 0.132 and 1.956 ng/mL. The precision (RSD) values of quality control samples (QC) had a maximum deviation of 4.9%. A comparison of the detection limits with similar methods indicates high sensitivity of the present method. The method is applied for the analysis of these drugs in real urine and plasma samples of epileptic patients.

A novel microextraction by packed sorbent–gas chromatography procedure for the simultaneous analysis of antiepileptic drugs in human plasma and urine

A simple, accurate, and sensitive microextraction by packed sorbent-gas chromatography-mass spectrometry method has been developed for the simultaneous quantification of four antiepileptic drugs; oxcarbazepine, carbamazepine, phenytoin, and alprazolam in human plasma and urine as a tool for drug monitoring. Caffeine was used as internal standards for the electron ionization mode. An original pretreatment procedure on biological samples, based on microextraction in packed syringe using C(18) as packing material gave high extraction yields (69.92-99.38%), satisfactory precision (RSD < 4.7%) and good selectivity. Linearity was found in the 0.1-500 ng/mL range for these drugs with limits of detection (LODs) between 0.0018 and 0.0036 ng/mL. Therefore, the method has been found to be suitable for the therapeutic drug monitoring of patients treated with oxcarbazepine, carbamazepine, phenytoin, and alprazolam. After validation, the method was successfully applied to some plasma samples from patients undergoing therapy with one or more of these drugs. A comparison of the detection limit with similar methods indicates high sensitivity of the present method over the earlier reported methods. The present method is applied for the analysis of these drugs in the real urine and plasma samples of the epileptic patients.

Determination of cobalt(II), nickel(II) and palladium(II) Ions via fabric phase sorptive extraction in combination with high-performance liquid chromatography-UV detection

ABSTRACT A method for the determination of Co(II), Ni(II) and Pd(II) in aqueous samples by fabric phase sorptive extraction-high-performance liquid chromatography-UV detection (FPSE-HPLC-UV) is developed. A preconcentration step was necessary due to the trace level concentrations of these elements in aqueous samples. Sol-gel polytetrahydrofuran nanocomposite was selected as the sorbent. All major FPSE parameters were optimized. The limit of detection for Co(II), Ni(II) and Pd(II) morpholino dithiocarbamate complexes were found at much lower concentration level compared with earlier reported data with excellent reproducibility. The new FPSE-HPLC-UV method can be used for routine determination of these metal species in various aqueous environmental samples and in different alloys.

A Review for the Analysis of Antidepressant, Antiepileptic and Quinolone Type Drugs in Pharmaceuticals and Environmental Samples

ABSTRACT The analysis of drugs in various biological fluids is an important criterion for the determination of the physiological performance of a drug. After sampling of the biological fluid, the next step in the analytical process is sample preparation. Sample preparation is essential for isolation of desired components from complex biological matrices and greatly influences their reliable and accurate determination. The complexity of biological fluids adds to the challenge of direct determination of the drug by chromatographic analysis, therefore demanding a sample preparation step that is often time consuming, tedious and frequently overlooked. However, direct online injection methods offer the advantage of reducing sample preparation steps and enabling effective pre-concentration and clean-up of biological fluids. These procedures can be automated and therefore reduce the requirements for handling potentially infectious biomaterial, improve reproducibility, and minimize sample manipulations and potential contamination. This review is focused on the discovery and development of high-performance liquid chromatography (HPLC) and gas chromatography (GC) with different detectors. The drugs covered in this review are antiepileptics, antidepressant (AD), and quinolones. The application of these methods for determination of these drugs in biological, environmental and pharmaceutical samples has also been discussed.

Development of a Rapid and Sensitive Method for the Determination of Aluminum by Reverse-Phase High-Performance Liquid Chromatography Using a Fluorescence Detector

This study represents a new analytical high-performance liquid chromatography-fluorescence detector method for the determination of Al(III) as Al(III) complex with 8-hydroxyquinoline-5-sulfonic acid in a tap water sample and a coke sample. A micellar liquid chromatographic method is proposed for the determination of aluminum metal in the presence of cetyltrimethylammonium bromide, a cationic surfactant (0.05 M) used for the solubilization of the aluminum complex. The influence of pH and ligand concentration on the formation of the complex was studied by adding a small amount of 0.1 M sodium hydroxide. The metal chelate was detected at λEx 410 nm and λEm 510 nm. This method eliminates the need for addition of reagent or organic modifier to the mobile phase. The complex was analyzed using an Ascentis Express C18 column and a mobile phase consisting of acetonitrile, methanol and water (55 : 30 : 15). Under the optimized conditions, the linear range was 1-200 µg L(-1) and the limit of detection was 0.05 µg L(-1). The method showed a good detector response over the range of interest and was successfully applied for the determination of trace Al(III) in canned coke and water samples containing excess of Mg(II), Ca(II) and other matrices.

A Review on Recent Applications of High-Performance Liquid Chromatography in Metal Determination and Speciation Analysis

ABSTRACT High-performance liquid chromatography (HPLC) has several advantages over the conventional methods due to their operational simplicity. It is a vital tool to determine metal ions having same mass but different electronic configuration, to separate complex mixtures and to resolve ions that may be indistinguishable by mass spectrometry alone. Metal ions play vital role in many biological processes and involved in setting up of many diseases. Therefore, the development of simple methods for the detection and quantification of metals in real samples might serve as diagnostic tools for various diseases. This review article focuses on the recent main feature of this technique, i.e. speciation of metal ions and their applications to series of problem of metal ion chemistry in different environmental matrixes. Speciation of metals is of increasing interest and has a great importance because of bioavailability, environmental mobility, toxicity and potential risk of metals. With the capability of partitioning the complex species of different metal ions, HPLC is an efficient technique for this task. This review summarizes recent advances in the development of HPLC to the fundamental understanding of metal ion chemistry in the environment and discusses all the issues that still need a lot of consideration. It has been classified into different sections depending on the role of HPLC in separation used and metal speciation; furthermore, the underlying sample preconcentration techniques and detection systems involved for the determination of metal ions and their applications were discussed.

Determination of endosulfan isomers and their metabolites in tap water and commercial samples using microextraction by packed sorbent and GC–MS

A simple, rapid, accurate and sensitive method using microextraction by packed sorbent (MEPS) followed by GC-MS has been pursued for the determination of organochlorine insecticide endosulfan isomers (α and β) and their metabolites (ether, lactone and sulfate). MEPS is a miniaturised version of SPE employing C18 packing material. It is very efficient technique as it employs as low as 10 μL of sample volume. The distinct feature of MEPS is the magnitude of the elution volume that could be directly injected to GC system. Various parameters such as extraction cycles, washing solvent, elution solvent, elution volume and pH, which influenced the MEPS performance, were tested and optimised. The calibration curves were obtained in the concentration range 1-500 ng/mL. The results showed a close correlation coefficient (R(2) > 0.991) for all analytes in the calibration range studied. The LOD and LOQ obtained for GC-MS under selected ion monitoring acquisition are between 0.0038-0.01 and 0.0125-0.033 ng/mL, respectively. The developed method is applicable for the quantification of these compounds in tap water and commercial samples. This method has been shown to be selective as no interferences from endogenous substances were detected by analysis. This method not only decreases sample preparation time but is cheaper, eco-friendly and easier to perform compared to traditional techniques.

Microextraction by Packed Sorbent–High-Pressure Liquid Chromatographic–Ultra Violet Analysis of Endocrine Disruptor Pesticides in Various Matrices

Microextraction by a packed sorbent (MEPS) is the miniaturized version of solid-phase extraction whereby sample volumes as small as 10 μL can be used. A syringe (100-250 μL) is used in MEPS technique, which generally contains 4 mg of solid packing material inserted as a plug. The sample preparation occurs on the surface of this bed which can be modified to provide varied sampling conditions. In the present work, MEPS has been employed as a sample preparation technique for the analysis of endocrine disruptor (ED) and suspected ED pesticides in biological and environmental samples. The pesticides aldicarb, dimethoate, propazine and terbutryn have been successfully separated by high performance liquid chromatography-ultra violet (HPLC-UV) system with acetonitrile/water as the mobile phase in the ratio 60/40. Several factors affecting the performance of MEPS technique such as the number of extraction cycles, type of washing and elution solvent were optimized. This method has been applied to the analysis of these pesticides in urine, soil and tap water samples with good recoveries in the range of 81.4-97.8%. The detection limit ranged between 0.05 and 0.6 ng mL for the analyzed pesticides.

Development of Microextraction by Packed Sorbent - Gas Chromatography-MassSpectrometry Method for Quantification of Nitro-Explosives in Aqueous andFluidic Biological Samples

A new method for quantification of twelve nitroaromatic compounds including 2,4,6-TNT, its metabolites and Tetryl with microextraction by packed sorbent (MEPS), followed by gas chromatography - mass spectrometric (GC-MS) detection in environmental and biological samples is developed. MEPS employ 4 mg of C18 silica sorbent inserted into a micro-volume syringe for sample preparation. Several parameters capable of influencing the microextraction procedure viz., number of extraction cycles, washing solvent, volume of washing solvent, elution solvent, elution solvent volume and pH of matrix etc., were optimized. Helium gas was used as mobile phase during GC operation. The developed method produced satisfactory results with excellent values of coefficient of determination (R2>0.9804) within the established calibration range. The extraction yields were satisfactory for all analytes (>89.32%) for aqueous samples and (>87.45%) for biological samples. The limits of detection values lie in the range 14 - 828 pg/mL. Due to procedural simplicity, high sensitivity and efficient resolution of all analytes, the developed method was applied successfully for quantification of nitro aromatic explosives in real aqueous and fluidic biological samples.