Chromatographic analysis of tetracycline antibiotics in foods

Tetracycline antibiotics (TCs), such as oxytetracycline, tetracycline, chlortetracycline, and doxycycline, have for decades continued to play an important role in veterinary medicine and feed additives because of the broad spectrum antibiotics and their economical advantages. Many analysis methods of TCs, therefore, have been reported to monitor their residues in foods. We review the recent developments in chromatographic analysis methods for TCs in foods. This review involves the following techniques: thin layer chromatography, capillary electrophoresis, high-performance liquid chromatography, and sample preparation including extraction and clean up procedures.     

碳点在抗生素分析检测中的应用

抗生素的过度使用对环境造成了极大破坏,对其进行监测控制刻不容缓。常用的分析检测技术,如高效液相色谱(HPLC)、气相色谱(GC)、高效液相色谱-串联质谱(HPLC-MS/MS)等具有高效快速、重现性好、可自动化操作等优点。但对环境样品中抗生素的检测存在样品前处理过程繁琐、检测灵敏度低、实验成本高等问题。结合现有的检测技术发展新型材料,对提高抗生素的检测灵敏度具有重要意义。碳点(CDs)是一种尺寸介于0~10 nm之间的新型纳米材料,具有小尺寸效应、优异的电学和光学性质、良好的生物相容性等优点,已被广泛应用于环境样品中抗生素的检测。该综述对近5年CDs与传感器、色谱分析技术结合检测抗生素的应用进行了总结,并对其发展前景进行了展望。该文总结了CDs与分子印迹传感器、适配体传感器、电化学发光传感器、荧光传感器及电化学传感器相结合,及其在抗生素检测中的应用;对涉及的比率型传感器、阵列传感器等先进分析方法进行了举例评述;对CDs作为色谱固定相分离抗生素进行了阐述。文献表明,CDs结合传感器检测抗生素可有效提高检测灵敏度,但对复杂环境样品中抗生素的检测还面临着构建高选择性传感器、开发新型材料及数据处理等方面的挑战;目前,CDs作为色谱固定相对抗生素的材料分离,仍处于初步研究阶段,分离机理尚不明确,有待进一步深入研究。总之,CDs在环境样品中抗生素的检测方面仍面临一系列问题,随着人们对CDs的深入研究以及各种分析检测技术的不断发展,CDs将会在抗生素等环境污染物的检测中发挥重要作用。     

Chromatographic identification of pesticides

The chromatographic properties of 51 common pesticides have been measured using seven different chromatographic systems involving gas-liquid chromatography (GLC), high-performance liquid chromatography (HPLC) with diode-array spectrophotometric detection and thin-layer chromatography (TLC) with different spray reagents. Correlation coefficients were calculated for combinations of all systems. The best combination of the chromatographic systems examined for the identification of an unknown compound is GLC on OV-17, HPLC on ODS-Hypersil with acetonitrile-water as eluent and TLC using an isooctane-ethyl acetate solvent system.     

Chromatographic methods for analysis of aminoglycoside antibiotics.

Aminoglycosides are antimicrobial agents used frequently in treatment of human and animal diseases caused by aerobic, gram-negative bacteria. Because of the toxicity of these compounds, considerable effort has been attributed to analysis of aminoglycoside content in drug preparations, in serum and urine specimen in therapeutic drug monitoring, and in edible animal tissues in residue control. The present review emphasizes the analytical problems associated with aminoglycoside analysis. Screening methods based on microbiological and immunological procedures were briefly discussed. Gas chromatography and especially high-performance liquid chromatography appeared the most widely used chemical methods for the analysis of these compounds. Due to lack of volatility, chromophore, and hydrophility of aminoglycosides, most methods applied derivatization for enhancement of their chromatographic characteristics. The applicability and advantages of the various derivatization procedures were discussed in detail. A wide variety of detection methods, including mass spectrometry have been used. Packed column separation was generally used for gas chromatographic separation. In liquid chromatography, reversed phase, ion pair, ion exchange, and normal phase separation has been employed. Mass spectrometry, as a detection method, was discussed in detail. Extraction procedures from body fluids and tissues were emphasized. The performance and the operational conditions of the methods were described and detailed information of the data was provided also in table format.     

Phycotoxins in seafood--toxicological and chromatographic aspects.

Two typical clinical types of algae-related seafood poisoning have attracted medical and scientific attention: paralytic shellfish poisoning (PSP) and diarrhetic shellfish poisoning (DSP). Therefore, it became necessary to establish methods for the evaluation of possible hazards caused by contamination of seafood with these phycotoxins. Bioassays with mice or rats are the common methods for the determination of the toxin content of seafood. However, biological tests are not completely satisfactory because of a lack of sensitivity and pronounced variations. Additionally, there is growing opposition against animal testing. Therefore, many efforts have been undertaken to determine phycotoxins by chromatographic methods. PSP determination is mainly based on high-performance liquid chromatographic (HPLC) separation by ion-pair chromatography followed by postcolumn oxidation of the underivatized toxins in alkaline solution and fluorescence detection. HPLC methods for the determination of the DSP toxins okadaic acid (OA) and dinophysistoxin-1 (DTX-1) are characterized by precolumn derivatization with 9-anthryldiazomethane (ADAM) and/or 4-bromomethyl-7-methoxycoumarin (Br-Mmc), followed by chromatographic separation of the DSP esters formed and fluorescence detection. The chromatographic methods discussed in this review allow the rapid, sensitive and non-ambiguous determination of individual species of the two most important phycotoxins in seafood, PSP and DSP.     

Chromatography in authenticity and traceability tests of vegetable oils and dairy products: a review

The new applications of various chromatographic techniques such as gas-liquid chromatography, high-performance liquid chromatography and electrophoretic methods employed for the analysis in macro- and micro-components in vegetable oils and dairy products are compiled and critically evaluated. The employment of these methods for authenticity tests and traceability is discussed.     

Chromatographic separation of tocopherols.

alpha-, beta-, gamma-, and delta-Tocopherols were separated by reversed-phase high-performance thin-layer chromatography (C18RP-HPTLC), normal-phase high-performance liquid chromatography (NP-HPLC), reversed-phase high-performance liquid chromatography (C18RP-HPLC), and gas chromatography (GC). The selected topological indices based on connectivity (M, 1chi(v)), on distance matrix (W, (o)B, MTI) and on information theory (I(AC), I(AC)) were calculated for these tocopherols. The observed chromatographic separations of investigated tocopherols were compared. This comparison indicated that the C18RP-HPTLC, NP-HPLC, and GC are the best techniques for the separation of these tocopherols. Topological index (o)B was the most significant. We obtained definite dependence between the numerical values of topological index (o)B and the chromatographic separation of the investigated tocopherols.     

Chromatographic methods for the analysis of heterocyclic amine food mutagens/carcinogens.

A series of potent heterocyclic amines that are mutagenic and carcinogenic have been discovered that are formed in some heated foods, most notably, meats derived from muscle. Determining the heterocyclic amine content in foods and food products is required for toxicological research, industry quality control, and possibly in the future, regulatory control. The contents of food needs to be determined using reliable analytical techniques. Since heterocyclic amines are present in foods at ng/g levels, a variety of liquid-liquid or solid-phase purification techniques are required, followed by gas or high-performance liquid chromatography. Peak detection has been successful using UV, fluorescence, and mass spectrometric detection, and biological activity using the Ames/Salmonella test. The low levels present require that chromatographic efficiency, and both detector sensitivity and selectivity be optimized. The cartridge solid-phase extraction and high-performance liquid chromatography method have been used to measure the known food-derived heterocyclic amines for several types of food, and to the authors knowledge, this is the only method undergoing intralaboratory comparison and validation. Our analysis of the literature shows that chromatographic analysis of the heterocyclic amines by high-performance liquid chromatography or gas chromatography (with derivatization) is satisfactory for heterocyclic amine analysis in foods although the methods are just now being optimized for routine use. The biggest improvements in speed and accuracy will probably come from improved extraction methods as analysis of complex food samples for heterocyclic amines will always be a challenge.     

Determination of Ro 14-1761, a new third-generation cephalosporin, in the plasma and milk of cattle by column switching high-performance liquid chromatography

A sensitive and specific high-performance liquid chromatographic procedure was developed for the determination of the third-generation cephalosporin Ro 14-1761 in cow plasma and milk. The molecular structure of the new antimicrobial was very close to that of ceftriaxone, but the high-performance liquid chromatographic methods available for the latter could not be used as Ro 14-1761 adsorbed and/or degraded during the chromatographic process. Furthermore, the high-performance liquid chromatographic technique derived for ceftriaxone was not sensitive enough for our purposes. In the new assay, the plasma (milk) protein was precipitated with acetonitrile after dilution of the sample with water. For low concentrations (less than or equal to 10 micrograms/ml), the supernatant obtained after centrifugation was concentrated by extracting acetonitrile with methylene chloride. Quantification was performed by column switching high-performance liquid chromatography with UV detection (274 nm) using ion-pair reversed-phase chromatography. Ethylenediaminotetraacetic sodium salt had to be added to the mobile phase (1.2 mM) to prevent adsorption and/or degradation of the cephalosporin on the analytical column. The selectivity of the chromatographic separation was enhanced by heating the column to ca. 50 degrees C. The drug recovery was better than 85%. The limit for quantitative determination in both milk and plasma was 0.1 microgram of Ro 14-1761 per millilitre with an accuracy of 1% (coefficient of variation 10%). The overall accuracy and precision were 1-10% in the 0.1-100 micrograms/ml concentration range.     

茶多酚的色谱分析法

 对茶多酚的主要成分――儿茶素的色谱分析法进行了综述。重点介绍了应用最多的反相高 效液相色谱法,同时简述了平板色谱法、气相色谱法以及目前出现的新的色谱分析方法。     

Chromatographic methods as tools in the field of mycotoxins

Achievements in the applications of chromatographic techniques in mycotoxicology are reviewed. Historically, column chromatography (CC) and paper chromatography (PC) were applied first, followed by thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC) and gas chromatography (GC). Although PC techniques are no longer used in the analysis of mycotoxins, selected applications of PC are included to underline historical continuity. The most important achievements published from 1980 onwards are described. They include clean-up methods, TLC, CC, HPLC and GC of mycotoxins in environmental samples, foods, feeds, body fluids and in studies on biosynthesis and biotransformations of mycotoxins. Advantages and disadvantages of chromatographic techniques used in mycotoxicology are also evaluated.     

Recent progress in carbohydrate separation by high-performance liquid chromatography based on hydrophilic interaction

This article surveys recent developments in the separation and analysis of carbohydrates by high-performance liquid chromatography, in adsorption or partition modes, on polar sorbents with less polar eluents, a technique that is now termed hydrophilic interaction chromatography. A variety of chromatographic methods are included under this generic heading, the most important being adsorption chromatography on silica and partition chromatography on silica-based sorbents bearing bonded polar phases. Examples are given of the applications of these stationary phases, as well as the newer polymer-based polar sorbents, in high-performance liquid chromatography of carbohydrates and their derivatives.     

十二烷基键合氧化锆固定相的制备与性能评价

以自制5μm球形氧化锆为基质，制备了十二烷基键合氧化锆HPLC固定相，考察了正烷基取代苯、稠环芳烃、苯胺及吡啶衍生物、苯酚和硝基苯酚异构体等不同性质化合物在固定相上的保留行为，并与十二烷基键合硅胶固定相进行了比较。结果表明：中性和碱性化合物在固定相上主要为反相色谱保留机理；酸性化合物在固定相上以反相色谱保留机理为主，但是氧化锆表面的Lewis酸性中心对溶质也存在一定程度吸附作用，导致色谱峰拖尾。     

A review of chromatographic methods for the assessment of phospholipids in biological samples

Phospholipids are important constituents of all living cell membranes. Lipidomics is a rapidly growing field that provides insight as to how specific phospholipids play roles in normal physiological and disease states. There are many analytical methods available for the qualitative and quantitative determination of phospholipids. This review provides a summary of the methods that were historically used such as thin layer chromatography, gas chromatography and high-performance liquid chromatography. In addition, an introduction to applications of interfacing these traditional chromatographic techniques with mass spectrometry is provided.     

Recent advances in metal‐organic frameworks and covalent organic frameworks for sample preparation and chromatographic analysis

In the field of analytical chemistry, sample preparation and chromatographic separation are two core procedures. The means by which to improve the sensitivity, selectivity and detection limit of a method have become a topic of great interest. Recently, porous organic frameworks, such as metal‐organic frameworks (MOFs) and covalent organic frameworks (COFs), have been widely used in this research area because of their special features, and different methods have been developed. This review summarizes the applications of MOFs and COFs in sample preparation and chromatographic stationary phases. The MOF‐ or COF‐based solid‐phase extraction (SPE), solid‐phase microextraction (SPME), gas chromatography (GC), high‐performance liquid chromatography (HPLC) and capillary electrochromatography (CEC) methods are described. The excellent properties of MOFs and COFs have resulted in intense interest in exploring their performance and mechanisms for sample preparation and chromatographic separation.     

Preparative high-performance liquid chromatography of peptides on a new reversed-phase packing material, Kromasil C18

Preparative reversed-phase high-performance liquid chromatography has found wide use in the production of peptides for pharmaceutical formulations. Purity of the substance and overall economy of the chromatographic system are the most important criterias. In this sense optimized, silica particles and production process with capability to separately control parameters important to chromatography, are essential to high-performance chromatography. Kromasil C18 packing material was tested and evaluated in respect of its selectivity, flow and pressure properties, resolution, load capacity, recovery, adsorption effects, mechanical strength and chemical degradation.     

Infrared methods for high throughput screening of metabolites: food and medical applications

Chemical and physiological properties are related to individual or bioactive compounds such as essential oils, terpenoids, flavonoids, volatile compounds and other chemicals which are present in natural products in low concentrations (e.g. ppm or ppb). For many years, classical separation, chromatographic and spectrometric techniques such as high performance liquid chromatography (HPLC), gas chromatography (GC), liquid chromatography (LC) and mass spectrometry (MS) have been used for the elucidation of isolated compounds from different matrices. Hence, the use of standard separation, chromatographic and spectrometric methods was found useful in chemical and both plant and animal physiology studies, for fingerprinting and comparing natural and synthetic samples, as well as to identify single active compounds. It has been generally accepted that a single analytical technique will not provide sufficient visualization of the metabolome, hence holistic techniques are needed for comprehensive analysis. In the last 40 years near infrared (NIR) spectroscopy became one of the most attractive and used methods of analyzing agricultural related products and plant materials which provide simultaneous, rapid and non-destructive quantitation of major. This technique has been reported to determine other minor compounds in plant materials such as volatile compounds and elements. The aim of this short review is to describe some recent applications of NIR spectroscopy combined with multivariate data analysis for high throughput screening of metabolites with an emphasis on food and medical applications.     

Hyphenated chromatographic methods for biomaterials

The improvement in hyphenated analytical techniques has significantly widened their applications to the analysis of biomaterials. In this article, we discuss recent advances in applications of hyphenated chromatographic techniques including capillary electrophoresis to the analyses of biological samples. As tools of separation, gas chromatography, high-performance liquid chromatography and capillary electrophoresis are considered with special emphasis on applications utilizing the hyphenation of these methods to mass spectrometry. Moreover, applications using other detection methods such as Fourier transform infrared spectroscopy hyphenated to gas chromatography and photodiode array detector combined with high-performance liquid chromatography or capillary electrophoresis are also discussed. Owing to their high sensitivity, luminescence-based detection systems such as laser-induced fluorescence and chemiluminescence are also included in this review.     

High-throughput analytical strategy with combined planar and column liquid chromatography for improvement of the poppy (Papaver somniferum L.) with a high alkaloid content

Summary Poppy capsules with a high alkaloid content are of great importance to the pharmaceutical industry, because approximately 35 000 tons of straw (capsule with short stem), 350 tons of straw concentrate, and 1000 tons of opium are used annually for extraction of morphinane alkaloids. The combined use of four different liquid chromatographic methods is proposed for determination of alkaloid content. In the first, semi-quantitative, method screening is performed by multilayer overpressured-layer chromatography (MLOPLC) in which 142 samples are separated on silica as stationary phase within 5 s per sample. If the morphine content is >1.3% it is then measured quantitatively by NPHPTLC (normal-phase high-performance thin-layer chromatography) combined with densitometric evaluation. A second, quantitative, determination is always performed by means of a rapid RPHPLC (reversed-phase high-performance liquid chromatography) method in which the separation time is less than 4 min per sample. If the difference between the alkaloid content measured by use of the last two methods is >12% a confirmatory RPHPLC method with increased selectivity and analysis time (15 min) must be used. The high throughput strategy presented has been used for analysis of ca. 15 000 samples per year, per genotype. Systematic selection, cross-breeding, and this analytical strategy with combined planar and column liquid chromatographic methods resulted in the discovery of two new candidate cultivars with high morphine (ca. 2%) and thebaine (ca. 1.5%) content. Presented at Balaton Symposium '01 on High-Performance Separation Methods, Siófok, Hungary, September 2–4, 2001.     

Chromatographic and electrophoretic techniques used in the analysis of triazole antifungal agents—a review

Systematic review of literature coupled with integrative research of published data for triazole antifungal agents was done. The investigated literature covered chromatographic and electrophoretic methods developed in the last 10 years (2000-2009). The aim of this review was to compare different methodologies, assess preferences in the selection of analytical methods and to find still existing analytical problems. Last decade is characterized by dynamic development of instrumental methods, that results in advance and diversity of applied analytical procedures. The main focus was given to high-performance liquid chromatography (HPLC), the technique of choice in the analysis of most of pharmaceuticals. The review includes literature on 8 triazole antifungal drugs: fluconazole, itraconazole and terconazole from the first generation and posaconazole, voriconazole, ravuconazole, isavuconazole and albaconazole classified in second generation. Investigations of pharmaceutical formulations and biological samples were considered.