Solid-phase extraction on alkyl-bonded silica gels in inorganic analysis.

Solid-phase extraction (SPE) is an effective tool for the preconcentration of trace elements and their separation from various sample constituents. Octadecyl and other alkyl-bonded silica gels are most widely used for these purposes. The fundamentals of the SPE of inorganic ions are reviewed and compared with those of related techniques (liquid-liquid extraction and reversed-phase liquid chromatography). The extraction of ions in the form of chelate compounds, inorganic salts solvated by neutral reagents, and ion-pair compounds is considered. Numerous applications of SPE to the separation and preconcentration of different elements and their species, including on-line combinations with instrumental determination techniques, are described and tabulated.     

食品中维生素D与25-羟基维生素D检测技术及含量分布研究进展

维生素D是一种对于维持人体健康具有重要作用的脂溶性维生素,25-羟基维生素D是其在人体内循环和存储的主要形式。食品中维生素D和25-羟基维生素D前处理的通常采用碱皂化、有机溶剂提取、固相萃取或者半制备色谱净化;其测定方法多为放射免疫法和液相色谱法。液相色谱串联质谱凭借高灵敏度和高准确度,目前在食品中维生素D和25-羟基维生素D测定中发挥重要作用。近年来二维液相色谱和超高效超临界流体色谱由于其强大的分离能力,在食品中维生素D和25-羟基维生素D的分析中表现出强大的潜力。该文综述了近年来食品中维生素D和25-羟基维生素D的检测方法及二者在动物食品和植物食品中的含量分布研究,以期为建立适合不同食物样品的测定方法,指导居民合理膳食,进行膳食摄入量评估等研究工作提供参考。     

HPLC separation of heterocyclic beta-diketonates of actinide, lanthanide and transition metals

Liquid-chromatography conditions for the separation of neutral chelates of 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone with transition metals, lanthanides and actinides have been established. The use of reverse-phase liquid chromatography, instead of ion-exchange, is a novel approach for actinide separation. The high molar absorptivities of the beta-diketonates in the ultraviolet region allow for their detection at the nanogram level. The potential exists, therefore, for the rapid solvent extraction, concentration and determination of traces of actinides and other metals.     

The recent developments in dispersive liquid–liquid microextraction for preconcentration and determination of inorganic analytes

Recently, increasing interest on the use of dispersive liquid–liquid microextraction (DLLME) developed in 2006 by Rezaee has been found in the field of separation science. DLLME is miniaturized format of liquid–liquid extraction in which acceptor-to-donor phase ratio is greatly reduced compared with other methods. In the present review, the combination of DLLME with different analytical techniques such as atomic absorption spectrometry (AAS), inductively coupled plasma-optical emission spectrometry (ICP-OES), gas chromatography (GC), and high-performance liquid chromatography (HPLC) for preconcentration and determination of inorganic analytes in different types of samples will be discussed. Recent developments in DLLME, e.g., displacement-DLLME, the use of an auxiliary solvent for adjustment of density of extraction mixture, and the application of ionic liquid-based DLLME in determination of inorganic species even in the presence of high content of salts are presented in the present review. Finally, comparison of DLLME with the other liquid-phase microextraction approaches and limitations of this technique are provided.     

The use of separation techniques in the analysis of some antiepileptic drugs: A critical review

In the last few decades, many new antiepileptic drugs came out to medicine world, and their use was expanded over a wide range of cases. Analysts from all over the world developed many different separation methods for the determination of these drugs in a quantitative way either in pharmaceutical dosage forms or in biological fluids. In this review article, a summation of previously published separation methods including high-performance thin-layer chromatography, high-performance liquid chromatography, gas chromatography, and electrophoresis used for the determination of eslicarbazepine acetate, levetiracetam, lacosamide, oxcarbazepine, pregabalin, and retigabine are presented. These six drugs are the most commonly used drugs for the treatment of patients diagnosed with partial onset seizures. This article can help researchers and analysts to build upon this knowledge and add further methods of analysis in the future.     

Erratum to: UPLC versus HPLC on Drug Analysis: Advantageous,Applications and Their Validation Parameters

Liquid chromatography (LC) is a separation technique used in many different areas to aid the identification and quantification of substances in various matrices. LC techniques with various detection modes have been widely used for the sensitive and selective determination of trace amounts of pharmaceutical active compounds in biological samples and their dosage forms. A completely new system design with advanced technology has been developed, called ultra high performance liquid chromatography, which has evolved from high performance liquid chromatography. The application of LC methods to drug analysis introduces a powerful tool for therapeutic drug monitoring as well as for clinical research. The advantages of short turnaround time, method reliability, method sensitivity, and drug specificity justify the use of LC techniques for various groups of the drug active compounds. This review describes some of the principles of ultra high performance liquid chromatography and high performance liquid chromatography, validation of these methods, system suitability tests for the methods, and application of methods to pharmaceutical analysis in the last 3 years.

     

UPLC versus HPLC on Drug Analysis: Advantageous, Applications and Their Validation Parameters

Liquid chromatography (LC) is a separation technique used in many different areas to aid the identification and quantification of substances in various matrices. LC techniques with various detection modes have been widely used for the sensitive and selective determination of trace amounts of pharmaceutical active compounds in biological samples and their dosage forms. A completely new system design with advanced technology has been developed, called ultra high performance liquid chromatography, which has evolved from high performance liquid chromatography. The application of LC methods to drug analysis introduces a powerful tool for therapeutic drug monitoring as well as for clinical research. The advantages of short turnaround time, method reliability, method sensitivity, and drug specificity justify the use of LC techniques for various groups of the drug active compounds. This review describes some of the principles of ultra high performance liquid chromatography and high performance liquid chromatography, validation of these methods, system suitability tests for the methods, and application of methods to pharmaceutical analysis in the last 3 years.     

Automated sample preparation using in-tube solid-phase microextraction and its application -- a review

Sample preparation, such as extraction, concentration, and isolation of analytes, greatly influences their reliable and accurate analysis. In-tube solid-phase microextraction (SPME) is a new effective sample preparation technique using an open tubular fused-silica capillary column as an extraction device. Organic compounds in aqueous samples are directly extracted and concentrated into the stationary phase of capillary columns by repeated draw/eject cycles of sample solution, and they can be directly transferred to the liquid chromatographic column. In-tube SPME is an ideal sample preparation technique because it is fast to operate, easy to automate, solvent-free, and inexpensive. On-line in-tube SPME-performed continuous extraction, concentration, desorption, and injection using an autosampler, is usually used in combination with high performance liquid chromatography and liquid chromatography-mass spectrometry. This technique has successfully been applied to the determination of various compounds such as pesticides, drugs, environmental pollutants, and food contaminants. In this review, an overview of the development of in-tube SPME technique and its applications to environmental, clinical, forensic, and food analyses are described.     

Latest achievements in the analytical chemistry of actinides

New methods for separation and determination of actinides, widely used in analysis of actinides in technological and environmental samples are reviewed. Special attention is paid to obtaining and stabilizing transplutonium elements. (TPE) in extreme oxidation states. Their use in analytical practice resulted in expanding possibilities of methods for separation and determination of TPE. Solvent extraction, sorption and extraction chromatography are the basic methods for separation of TPE. Solvent extraction, sorption and extraction chromatography are the basic methods for separation of TPE. Methods of separation in gas phase and some other methods such as precipitation and coprecipitation are applied, however, to a lesser degree. Trends of development of these methods including those of various types of membrane extraction that succeeded in separation of TPE in both trivalent and other valence states have been shown. Attention is paid mainly to consideration of modern methods for determination of actinides, special distinction of such methods being low limits of determination, high precision and selectivity. Alpha- and beta-spectrometric methods with semiconductor detectors are the most advanced among various methods based on registration of nuclear radiation. Tremendous success has been achieved in development of emission-spectrometric methods for determination of trace amounts of actinides and various impure elements occurring in samples of actinides. Sensitive mass-spectrometric methods are widely used for determination of both isotope composition and content of elements in various samples including those which are highly radioactive. More simple and precise titrimetric methods based on using oxidizing-reducing or complexing agents are developed successfully. A large number of coulometric methods for determination of americium and berkelium, characterizing high precision and selectivity as well as luminescence methods have been developed.     

Analytical methods for determination of new fluoroquinolones in biological matrices and pharmaceutical formulations by liquid chromatography: a review

Fluoroquinolones are one of the most promising and intensively studied drugs of contemporary anti-infective chemotherapy. New fluoroquinolone antibacterials with improved pharmacokinetic properties and a broad spectrum of activity have been developed, opening new windows of opportunity for clinical use. To our knowledge, no comprehensive and critical review of the analytical methods for the determination of these agents, which correspond to the third- and fourth-generation quinolones, has yet been published. This work summarizes for the first time most of the liquid chromatographic methods reported in the literature for the separation and quantification of the new fluoroquinolones in biological matrices and pharmaceutical formulations. A systematic and detailed survey of physicochemical properties, sample preparation procedures, and chromatographic and detection conditions is presented herein. In the course of this review several liquid chromatographic methods are discussed: reversed-phase high-performance liquid chromatography (RP-HPLC), ion-exchange high-performance liquid chromatography (IEX-HPLC), hydrophilic interaction liquid chromatography (HILIC), high-performance thin-layer chromatography (HPTLC) and other chiral chromatographic methods. Their advantages, applicability and limitations are also examined.     

A new and fast strategy based on semiautomatic microextraction by packed sorbent followed by ultra high performance liquid chromatography for the analysis of drugs and their metabolites in human urine

A novel analytical approach has been developed for the determination of selected drugs (milrinone, enalapril, carvedilol, spironolactone, acenocumarol, ticlopidine, cilazapril) and their metabolites (2‐oxoticlopidine, cilazaprilat, canrenone, 5′‐hydroxycarvedilol, O‐desmethyl‐carvedilol, enalaprilat) in human urine, based on a miniaturized extraction technique; semiautomatic microextraction by packed sorbent, using a new digitally controlled syringe, followed by ultra high pressure liquid chromatography separation combined with UV detection. During method optimization, the extraction parameters as the type of sorbent material, type and volume of elution solution, number of extraction cycles, volume and pH of sample, type and volume of washing solution were studied. The chromatographic separation of the target analytes was performed with a core–shell analytical column using 0.05% trifluoroacetic acid in water and acetonitrile in gradient elution mode. The limits of quantification ranged from 0.016 to 0.045 μg/mL. Under the optimized conditions, extraction efficiency was higher than 70.1% for drugs and their metabolites. Due to its simplicity and speed, this method was successfully applied to the quantitation of selected compounds in urine samples.     

Determination of Methamphetamine and Amphetamine by High-Performance Capillary Electrophoresis with UV Detection

Methamphetamine and amphetamine are well-known illicit drugs that have'a potent central nervous system stimulating effect. It is reported that methamphetamine is more addictive than heroin. The abuse of amphetamine and methamphetamine is increasing because they can be easily manufactured. There have been increasing interested in the development of analysis methods for methamphetamine and amphetamine. The determination of methamphetamine and amphetamine by gas chromatography (GC),GC-mass spectrometry (GC-MS), polarization fluoroimmunometry and high-performance liquid chromatography (HPLC) have been reported. Recently, Kuroda and Trenerry have reported the separation of these two compounds by CE.     

Characteristics and enantiomeric analysis of chiral pyrethroids

Pyrethroids are synthetic pesticides that originated from the modification of natural pyrethrins to improve their biological activity and stability. They are a family of chiral pesticides with a large number of stereoisomers. Enantiomers of synthetic pyretroids present different insecticidal activity, toxicity against aquatic invertebrates and persistence in the environment so the development of rapid and sensitive chiral methods for the determination of different enantiomers is necessary. Several techniques have been employed for this purpose including gas chromatography, high performance liquid chromatography or more recently capillary electrophoresis and sub or supercritical fluid chromatography. A general view on the different chiral separation methods applied to the analysis of pyrethroids and the most important information about these pesticides is provided in this review.     

Multi-residue quantification of veterinary drugs in milk with a novel extraction and cleanup technique: Salting out supported liquid extraction (SOSLE)

A quantitative liquid chromatography coupled with high-resolution mass spectrometry method was developed for the determination of more than one hundred compounds belonging to a variety of veterinary drug classes in bovine milk. Salting out supported liquid extraction (SOSLE), a novel extraction and cleanup technique, was introduced to ensure high extraction efficiency and good sample cleanup. The high salt (ammonium sulfate) concentration in the aqueous donor phase permits supported liquid/liquid extraction (SLE) with a relative polar organic acceptor phase (acetonitrile). This is different from traditional SLE, in which the need for phase separation results in the selection of organic solvents with intermediate polarities (e.g., ethyl acetate or dichloromethane). Hence, SOSLE is more efficient in recovering polar analytes than conventional SLE. SOSLE was also compared to classical approaches like solid phase extraction, QuEChERS and ultra-filtration. The proposed technique resulted in extracts of equal or superior cleanliness and with higher average recoveries than those obtained with QuEChERS or SPE. The recovery (median for all compounds) was 73% for QuEChERS, 83% for SPE and 91% for SOSLE. The most significant improvements were observed for polar analytes (penicillines, quinolones and tetracyclines) which are hardly recovered by QuEChERS. The chromatographic separation and detection was based on an ultra-high-performance liquid chromatography Q-Orbitrap system (Q-Exactive plus). The developed analytical method has been validated (based on the commission decision 2002/957/EC) as required for quantitative veterinary drug methods.     

Selectivity of catalytic methods of determination

By means of catalytic analytical methods, extremely low levels can be determined at low cost and with a high sensitivity that is equal to that of physical methods of trace analysis. The selectivity of the catalytic determinations, is, however, usually rather lower than that of other methods of trace analysis. The selectivity can sometimes be improved by modification of the indicator reaction through variation of the reagents and their concentrations, or by use of masking reagents or activators, or by combination with a separation method. Modification of the indicator reaction can be exemplified by the selective determination of osmium and ruthenium by their catalysis of the nitrate oxidation of 1-naphthylamine. By variation of the nitrate concentration and the use of 1,10-phenanthroline and 8-hydroxyquinoline as complexing agents it is possible to determine these two elements simultaneously. An especially significant increase in the selectivity is made possible by use of a preliminary separation step. If the ion to be determined is separated by solvent extraction and then catalytically determined directly in the extract, a very specific determination is possible; this technique has been called "extractive catalytic determination". This method has been used for determination of molybdenum (0.5 ng/ml) in sea-water, iron (5 ng/ml) in heavy metal salts, and copper (3 ng/ml) in the presence of numerous elements.     

生物样品中短链脂肪酸的提取与测定

综述了生物样品(主要为粪便、尿液、血液和培养液)中短链脂肪酸的提取与测定方法,讨论了各种样品提取方法的优缺点,并比较了气相色谱、高效液相色谱和毛细管电泳分离检测的优点和局限性。引用文献63篇。     

Recently developed GC/MS and LC/MS methods for determining NSAIDs in water samples

Pharmaceuticals have become major targets in environmental chemistry due to their presence in aquatic environments (following incomplete removal in wastewater treatment or point-source contaminations), threat to drinking water sources and concern about their possible effects to wildlife and humans. Recently several methods have been developed for the determination of drugs and their metabolites in the lower nanogram per litre range, most of them using solid-phase extraction (SPE) or solid-phase microextraction (SPME), derivatisation and finally gas chromatography mass spectrometry (GC-MS), gas chromatography tandem mass spectrometry (GC-MS/MS) and liquid chromatography electrospray tandem mass spectrometry (LC-ES/MS/MS). Due to the elevated polarity of non-steroidal anti-inflamatory drugs (NSAIDs), analytical techniques based on either liquid chromatography coupled to mass spectrometry (LC-MS) and gas chromatography coupled to mass spectrometry (GC-MS) after a previous derivatisation step are essential. The most advanced aspects of current GC-MS, GC-MS/MS and LC-MS/MS methodologies for NSAID analysis are presented.     

Direct coupling of microcolumn liquid chromatography with in-tube solid-phase microextraction for the analysis of antidepressant drugs

The direct coupling of in-tube solid-phase microextraction (in-tube SPME) with microcolumn liquid chromatography (micro-LC) has been investigated for the analysis of antidepressants in human urine. The use of in-tube SPME has been clearly shown to be advantageous for the on-line coupling of the SPME method, as the sample pretreatment technique, with micro-LC as the separation technique. This is because much smaller amounts of the sample solutions, desorption solvents and the mobile phase are required compared with conventional SPME-LC systems. The parameters for preconcentration have been investigated for the extraction capillary with the newly developed 'wire-in-tube' configuration.     

Capillary electrophoresis in the analysis of pharmaceuticals in environmental water: A critical review

Determination of residual pharmaceutical compounds in environmental water is gaining increasing interests. The task represents a substantial challenge to analysts because analytes present in quite complicated matrices and at very low concentrations. Despite the inherent low sensitivity associated with capillary electrophoresis (CE), it has been used successfully to determine different types of pharmaceutical compounds at very low levels that rival those reported by more commonly used methods for that purpose such as high performance liquid chromatography-mass spectrometry (HPLC-MS). Attempts to use CE for the determination of drugs in environmental water samples started nearly in the late 1990s; since then, different modes of CE including capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography together with different detection techniques (UV, fluorescence, MS) have been investigated and shown to be of adequate performance. A key to the success of CE for such low-level determination was the sample concentration steps that have been used including solid-phase extraction and more advanced approaches such as in-line sample concentration, large volume sample stacking, and others. The different reports that have been reported for this application in particular have been reviewed since late 1990s with emphasis on the attained limits of detections and sample treatment. The particularities of the separation conditions in each case have been discussed with some elaboration.