Comparison of photon activation analysis with other modern analytical methods as tools for the solution of actual analytical problems

A 35 MeV linear electron accelerator is used to investigate how far photon activation analysis can be used within the broad spectrum of analytical methods applied in BAM. The irradiation facilities are described. Examples are given for the application of PAA in the analysis of oxygen in metals and compared with conventional heat extraction and other nuclear analytical methods. It is further shown that PAA is a very useful tool for the analysis of traces of noble metals in Cu compared with other methods. Finally the possibilities of PAA in the field of multielement analysis are demonstrated taking ancient roman potsherds and bronze as examples. The results are compared with those of XRF and AAS. It is concluded that PAA is a valuable tool in the analysis of light elements with at least partly unique possibilities, that it can serve as an independent method for the certification of Reference Materials in many cases and that PAA can be very useful applied for multielement analysis.     

Chemical methods in association with physical methods in drug analysis

Physical methods, namely spectroscopy and separation techniques such as high-performance liquid chromatography, in which the analyte is not chemically changed during analysis, have gained increasing popularity in the field of pharmaceutical analysis. Nevertheless, chemical manipulation in combination with such methods will continue to play a vital role, as will be demonstrated with examples selected from methods developed for two new, cardioactive drugs, nadolol and captopril, and from other recent literature references.     

Chemiluminescence and Spectrofluorimetric Methods for Determination of Fluoroquinolones: A Review

Fluoroquinolones are an important and extensively studied group of compounds. Newer generations of fluoroquinolones are being developed to enhance the antimicrobial spectrum and pharmacological properties of these antimicrobials. Various analytical methods including chromatographic, voltametric, titrimetric, potentiometric, spectrophotometric, and so forth have been reported for analysis of these drugs. However luminescence and spectrofluorimetric methods continue to hold much significance as they are simple, economical, and sensitive as compared to most of the other methods. This led us to review the luminescence and spectrofluorimetric methods described for the analysis of this important class of drugs either per se, in dosage forms, or in biological fluids.     

Bioanalytical methods for food contaminant analysis

Foods are complex mixtures of lipids, carbohydrates, proteins, vitamins, organic compounds, and other naturally occurring substances. Sometimes added to this mixture are residues of pesticides, veterinary and human drugs, microbial toxins, preservatives, contaminants from food processing and packaging, and other residues. This milieu of compounds can pose difficulties in the analysis of food contaminants. There is an expanding need for rapid and cost-effective residue methods for difficult food matrixes to safeguard our food supply. Bioanalytical methods are established for many food contaminants such as mycotoxins and are the method of choice for many food allergens. Bioanalytical methods are often more cost-effective and sensitive than instrumental procedures. Recent developments in bioanalytical methods may provide more applications for their use in food analysis.     

Rapid methods of polymer and polymer additives identification: Multi-sample solvent-free MALDI, pyrolysis at atmospheric pressure, and atmospheric solids analysis probe mass spectrometry

Polymer manufacturers add antioxidants, waxes, dyes, and other materials to enhance polymer utility or processing. Numerous analytical methods are available to characterize various chemical aspects of polymers including methods interfaced with mass spectrometry (MS) such as pyrolysis (Py), gas chromatography (GC), liquid chromatography (LC), and thermogravimetric analysis (TGA). Current methods work well, but because of the necessity of extraction, chromatography, or thermal methods, most are too time consuming for high throughput analyses which might be necessary in, for example, regulatory laboratories. Here we discuss three MS methods for rapid analysis of polymers; multi-sample MALDI MS which allows rapid analysis of low molecular weight polymers, atmospheric pressure (AP) solids analysis probe MS for direct ambient additives analysis, and APPy MS for polymer identification. The latter methods provide information regardless of the composition or molecular weight of the polymeric material.     

Interpretation and analysis of complex environmental data using chemometric methods

An overview of the application of chemometric data analysis methods to complex chemical mixtures in various environmental media is presented. Reviews of selected research are given as examples of the application of principal components analysis and other statistical methods to identify contributions from multiple sources of contamination in air, water, sediments, and biota. Other examples are cited that illustrate how scientists have used classification and regression methods to model the distribution of anthropogenic contaminants and predict their environmental effects or fate.     

Zur Methodik der Elementspezies-Analytik in Lebensmitteln

Summary Potentiometry with an ion-selective electrode as well as a cation-chelate-exchange procedure (combined with AAS) are presented as useful methods for the determination of stabilities of element species, for example of calcium in milk. The cation-exchange procedure is also applicable to other metals (e.g., magnesium) and other foodstuffs (e.g., meat extracts). New results of Ca- and Mg-extractabilities by the use of different aqueous extraction solutions (including enzymic solutions) are reported. Ultrafiltration, dialysis and gel-chromatography are further methods especially for the separation and analysis of protein-containing element species. Unoccupied binding fields can be detected after addition of Cu(II) ions by combination of gel chromatography and UV/VIS spectroscopy, as shown by example of rape-flour. The experiences gained in the analysis of element species in foodstuffs are combined to a strategy of analysis.     

Determination of element concentrations in biological reference materials by solid sampling and other analytical methods

Summary Using solid sampling with graphite furnace atomic absorption spectrometry (GFAAS), values for cadmium, copper, lead and zinc in six biological reference materials were obtained from up to four laboratories participating in three collaborative studies. These results are compared with those obtained with other methods used in routine analysis from laboratories of official food control. Under certain conditions solid sampling with GFAAS seems to be suitable for routine analysis as well as conventional methods.     

Are the results of customary methods for analyzing dioxin and dioxin-like compound congener profiles court-proof?

The congener profile of samples contaminated with dioxin and dioxin-like compounds allows identifying sources of contamination. This article studies the statistical methods of congener profile analysis reported in the literature with respect to the reliability of obtained results. The performance of customary analysis methods regarding raw data transformation and applied TEF (toxic equivalency factor) values is discussed. In particular, the method of principal component analysis and k-means cluster is taken as an example and examined in detail. Reasons for occurring inconsistencies such as the dependence of results on raw data transformation and the disregard of measurement uncertainty are described, and it is shown that they also explain inconsistencies in other methods of cluster analysis such as hierarchical cluster analysis and neural networks. It is concluded that these methods cannot be employed to reach court-proof decisions, i.e. decisions which meet court evidentiary standards. An alternative approach to analyzing congener profiles based on mathematical statistics is briefly presented, allowing reliable, court-proof decisions.     

An investigation of a flameless atomic-absorption method for determination of aluminium, calcium, iron and magnesium in sewage sludge

The methods currently used for the determination of aluminium, calcium, iron and magnesium in sewage sludge are time-consuming. A rapid flameless atomic-absorption procedure, utilizing homogenization of diluted samples as the only pretreatment, has been compared with wet and dry analytical methods followed by flame atomic-absorption analysis, in a statistically designed experiment. Low-sensitivity (secondary absorption) lines have been used for the flameless analysis. The flameless atomic-absorption method described is better than all the other methods tested, with the exception of the nitric-perchloric-hydrofluoric acid digestion procedure. The time saved is substantial and the method could be used advantageously for routine analysis.     

化学计量学在速差动力学分析中的应用及进展

化学计量学在动力学多组分分析中的应用是近年来非常活跃的领域。本文从多元校正、卡尔曼滤波、协同效应校正、人工神经网络及计算机应用等方面对化学计量学速差动力学分析领域出现的新方法及新动向作一评述,并对今后的工作进行了展望。引用文献99篇。     

Chromatographic determination of pesticides in soil: Current trends in analysis and sample preparation

Soil is a primary sink and reservoir for pesticides pollution and one of the priority objects in terms of pesticides safety guidelines. Pesticides’ analysis in soil is a field of research which is in constant development facing numerous challenges such as the increasing amount and variety of analytes and their combinations, as well as the increasing demand for faster, simpler, more accurate and multiresidue analysis. This review provides the summary of studies on pesticides analysis in soil based on chromatography-coupled methods published between 2015 and 2022. We discuss the shift toward faster, greener, and simpler alternatives to conventional techniques, application of sample preparation and detection methods to targeted and untargeted pesticide analysis, as well as the developments in stereoselective determination of chiral pesticides. The sample preparation methods such as solid-phase extraction, dispersive solid-phase extraction, and derived methods, as well as the recent trends and developments in chromatographic separation of pesticides are covered in this review. For sample preparation, the QuEChERS method is replacing other techniques and has proved to be efficient in both screening and accurate quantification in multiresidue analysis. Shift towards minimal sample preparation is supported by a wider application of highly sensitive and selective separation and detection systems such as LC-MS/MS. The features of different methods of sample preparation and detection are discussed with focus on optimal parameters, advantages, and drawbacks. The optimal parameters of sample preparation methods were summarized based on respective publications, which makes the review a useful tool for method development and further investigations.     

Miniaturized sample preparation combined with liquid phase separations

Miniaturized sample preparation methods designed as the sample pretreatment for liquid phase separations, such as liquid chromatography, capillary electrophoresis and capillary electrochromatography, have been reviewed especially for the on-line coupling of the sample preparation process and the separation process. The development of the desorption interfaces for the effective combining of the sample preparation and subsequent liquid phase separations is briefly described along with the applications of the combined analytical systems to the analysis of complex sample mixtures such as biological and environmental matrices. Novel use of fine polymeric filaments as the extraction medium for microscale liquid phase separation methods are investigated and a comparison is made with other sample preparation techniques. Polymer coating onto the fibrous material is also introduced to further develop microscale sample preparation methods with improved extraction performance. Several other microscale sample preparation methods having a potential compatibility to the liquid phase separations are also described for future applications of these techniques.     

Classification and Prediction of Geological Samples by Principal Component Analysis

The principal component analysis is an ancient multivariate statistical method[1]. It is extensively used in spectrometry with the popularization of computer and development of the method of chemometrics. It is regarded as an effective method of multivariate statistical analysis. The principal component analysis is universally included in common program package of multivariate statistical analysis. The method, as well as other multivariate calibration methods, combined with artificial neural networks forms the foundation of the chemometrics.     

Current analytical methods for plant auxin quantification – A review

Plant hormones, and especially auxins, are low molecular weight compounds highly involved in the control of plant growth and development. Auxins are also broadly used in horticulture, as part of vegetative plant propagation protocols, allowing the cloning of genotypes of interest. Over the years, large efforts have been put in the development of more sensitive and precise methods of analysis and quantification of plant hormone levels in plant tissues. Although analytical techniques have evolved, and new methods have been implemented, sample preparation is still the limiting step of auxin analysis. In this review, the current methods of auxin analysis are discussed. Sample preparation procedures, including extraction, purification and derivatization, are reviewed and compared. The different analytical techniques, ranging from chromatographic and mass spectrometry methods to immunoassays and electrokinetic methods, as well as other types of detection are also discussed. Considering that auxin analysis mirrors the evolution in analytical chemistry, the number of publications describing new and/or improved methods is always increasing and we considered appropriate to update the available information. For that reason, this article aims to review the current advances in auxin analysis, and thus only reports from the past 15 years will be covered.     

The analytical and chemometric procedures used to profile illicit drug seizures

Over the last 20 years there has been an increasing interest in the development of robust systems, both analytical and statistical, to enable the linkage of seizures of illicit drug to each other. Much of this work has concentrated on the analysis of synthetic drugs, such as amphetamine and its analogues. In recent years, the analysis of both organic and elemental impurities as well as isotope ratios has advanced the usefulness of the techniques available. The application of specific chemometric methods to the derived analytical data has begun to provide the possibility of robust methods by which the resultant information can be interrogated.     

Recent advances in the application of capillary electromigration methods for food analysis

This article reviews the latest developments in the application of capillary electromigration methods for the analysis of foods and food components. Nowadays, methods based on CE techniques are becoming widely used in food analytical and research laboratories. This review covers the application of CE to analyze amino acids, biogenic amines, peptides, proteins, DNAs, carbohydrates, phenols, polyphenols, pigments, toxins, pesticides, vitamins, additives, small organic and inorganic ions, chiral compounds, and other compounds in foods, as well as to investigate food interactions and food processing. The use of microchips as well as other foreseen trends in CE analysis of foods is discussed. Papers that were published during the period June 2002-June 2005 are included following the previous review by Frazier and Papadopoulou (Electrophoresis 2003, 24, 4095-4105).     

Analysis of resveratrol in wine by capillary electrophoresis

Capillary electrophoresis (CE) is a new analytical technique that has recently been reported as a method for analysis of resveratrol in wine. Several different separation approaches have been taken in these reports. In comparison with high-performance liquid chromatography (HPLC), CE methods have similar sensitivity and can discriminate between trans- and cis-isomers of resveratrol. CE methods also show promise for analysis of other flavonoid antioxidants (glycosides and aglycones) in wine.     

Microextraction techniques in the analysis of food flavor compounds: A review

Food flavor compounds due to the complexity of food as a matrix, and usually their very low concentrations in a product, as well as their low odor thresholds, create a challenge in their extraction, separation and quantitation. Food flavor volatiles represent compounds of different polarity, volatility and chemical character, which determine method of extraction for their isolation from food. Microextraction techniques, mainly SPME and SBSE have been used for food flavor compounds analysis for two decades. Microextraction methods other than SPME and SBSE are seldom used despite their analytical potential. The review discusses the nature of food flavor compounds, and different approaches to food flavor analysis. It summarizes the use of microextraction methods in food flavor compounds analysis based on papers published in the last 5 years, and discusses the potential of microextraction methods in this field.     

Electron microprobe analysis of micro amount powder samples: A case study on high purity coal

For the major, minor and trace element analysis of the inorganic compounds of a Ruhr-Saar coal different preparation techniques are investigated with X-ray fluorescence analysis, electron microprobe and classical wet chemical methods minimizing sample weight at standard preparation times and analytical accuracies. Considering accuracy as well as preparation efforts, determinations by electron microprobe on small sample amounts (<50 mg) proved to be superior to the other methods.Abbreviations AAS atomic absorbtion spectrometry - EMA electron microprobe analysis - IC ion chromatography - ISE ion sensitive electrode - PHOT photometry - WCA wet chemical analysis - XRF X-ray fluorescence analysis - LTA low temperature plasma ashing - HTA high temperature ashing - l.o.i. loss on ignition