Analytical procedure for the determination of thorium, zinc and potassium in diet samples

Instrumental neutron activation analysis (INAA), and atomic absorption spectrometry (AAS) have been used for the determination of trace amounts of thorium, zinc, and potassium in diet samples. Interlaboratory comparison has been made. The z-scores show that INAA can be used to determine thorium and zinc whereas AAS can be employed to determine potassium in diet samples.     

Multielement determination of typical diet reference materials by neutron-induced prompt gamma-ray analysis using k 0 standardization

Multielement determination in reference materials of diet and its relatedsamples has been studied by a k 0 based neutron-induced prompt gamma-ray analysis(PGA) by using cold and thermal guided neutron beams of JRR-3M at JAERI. Hydrogen,B, C, N, Na, S, Cl, K and Ca were determined in the reference materials ofNIES and NIST typical diet and milk powder samples. Analytical results ofthe NIST Standard Reference Materials agreed with the certified values towithin 7%.     

Analytical determination of homocysteine: a review

The determination of homocysteine has gained high interest within the biomedical community over recent years as the molecule is an important biomarker for a wide range of diseases. The current report gives a brief overview into the biological significance of homocysteine and a rigorous account of the existing detection protocols for homocysteine in biological fluids, as well as trying to anticipate possible future trends in the development of rapid, low-cost and sensitive assays for its detection.     

Adherence to the Mediterranean diet in a Sicilian student population

Since the last decades, socio-economic changes have a key role on eating habits affecting the nutritional status and health of people, in particular children and adolescents. The aim of this study was to compare the diet of student population both normal weight and overweight and obese in order to understand their eating habits by comparing the different diets of the student referring to the Mediterranean diet. The study comprised 337 Sicilian students aged 9 to 13 years, 96 in primary schools and 241 in secondary schools, respectively, in three Sicilian cities namely, Messina, San Piero Patti and Ragusa. The variables studied were height, weight, body mass index (BMI) and adherence to the Mediterranean Adequacy Index (MAI) diet quality indicator. Interestingly, the results highlighted 2.67 MAI mean value for normal weight students while 1.27 MAI mean value indicating a decreased adherence to the Mediterranean diet in overweight students.     

Analytical methods for the determination of tungsten

Methods developed and employed in the recent literature (1969-1975) for the detection and determination of tungsten in a wide variety of matrices are reviewed. This paper is a supplement to the books, monographs and review papers which deal with the earlier literature.     

Analytical methodologies for the determination of ticagrelor

Ticagrelor is an orally administered platelet aggregation inhibitor with a cyclopentyl‐triazolopyrimidine structure; it is a selective reversible P2Y12 receptor antagonist, which prevents P2Y12‐mediated and ADP‐mediated platelet activation and aggregation. It is used to reduce the rate of cardiovascular death, myocardial infarction and stroke in patients with acute coronary syndrome or history of myocardial infarction. Several analytical methods have been published for the determination of ticagrelor in pharmaceuticals and biological materials by spectrophotometry, high‐performance liquid chromatography with ultraviolet detection and liquid chromatography coupled with tandem mass spectrometry. The purpose of the current review is to provide a systematic survey of the analytical techniques used for the determination of ticagrelor since its introduction in therapy until today.     

Analytical procedure for the determination of chlorobenzenes in sediments

This study presents the procedure for the determination of chlorobenzenes in sediment. It consists of solvent extraction (shaking overnight), extract clean-up with the use of a homemade glass column packed with activated silica gel and freshly activated copper, and slow solvent evaporation to a volume of 0.3 mL. Two-microliter extract portions are analyzed by means of gas chromatography with an Rtx-624 capillary column (60 m x 0.32 mm, d(f) = 1.8 microm) coupled with mass spectrometry (in selected ion-monitoring mode). Deuterated 1,2-dibromobenzene is used as the recovery standard. The recovery of this method for all chlorobenzenes is high (ranging from 78% to 107%) with the exception of monochlorobenzene, which is 58%. The method is also characterized by good precision, which is commonly accepted in the analysis of trace organic pollution.     

Electrochemical determination of synthetic antioxidants of bisdithiophosphonic acids

It has been found that bisdithiophosphonic acids with aryl substituents at the phosphorus atom quantitatively interact with electrogenerated halogens under the conditions of galvanostatic coulometry. Stoichiometric coefficients of the reaction between synthetic antioxidants and coulometric titrants-halogens have been determined. The corresponding reaction schemes have been proposed. The total antioxidant capacity (TAC) of the analytes has been estimated by their reaction with electrogenerated bromine. It has been demonstrated that bisdithiophosphonic acids bearing ionolic fragments demonstrate the highest TAC. It has been established that bisdithiophosphonic acids are irreversibly oxidized on a glassy carbon electrode at a potential of 800 mV with 0.1 M NaClO₄ in acetonitrile as the supporting electrolyte. The quantification limit and the analytical range of the analyte determination have been found.     

Analytical determination of microelements in well waters

Well water analysis was carried out starting with liquid samples which have been evaporated to dryness. The salt deposit crust has ensured an enrichment in microelements which were approximately determined by emission spectroscopy. Once the order of magnitude was established, the exact measurements were carried out based on the following techniques: mass spectrometry, atomic absorption spectrophotometry, activation with slow neutrons, and γ-spectrometry. The results obtained are the average values of at least three methods employed. *** DIRECT SUPPORT *** A1353055 00005     

Analytical determination of polyphenols in olive oils

The increasing popularity of olive oil is mainly attributed to its high content of oleic acid, which may affect the plasma lipid/lipoprotein profiles, and its richness in phenolic compounds, which act as natural antioxidants and may contribute to the prevention of human disease. An overview of analytical methods for the measurement of polyphenols in olive oil is presented. In principle, the analytical procedure for the determination of individual phenolic compounds in virgin olive oil involves three basic steps: extraction from the oil sample, analytical separation, and quantification. A great number of procedures for the isolation of the polar phenolic fraction of virgin olive oil, utilizing two basic extraction techniques, LLE or SPE, have been included. The reviewed techniques are those based on spectrophotometric methods, as well as analytical separation (gas chromatography (GC), high-performance liquid chromatography (HPLC), and capillary electrophoresis (CE)). Many reports in the literature determine the total amount of phenolic compounds in olive oils by spectrophometric analysis and characterize their phenolic patterns by capillary gas chromatography (CGC) and, mainly, by reverse phase high-performance liquid chromatography (RP-HPLC); however, CE has recently been applied to the analysis of phenolic compound of olive oil and has opened up great expectations, especially because of the higher resolution, reduced sample volume, and analysis duration. CE might represent a good compromise between analysis time and satisfactory characterization for some classes of phenolic compounds of virgin olive oils.     

Analytical approaches for the determination of PCB metabolites in blood: a review

Polychlorinated biphenyls (PCBs) are among the most ubiquitous pollutants in the environment, and their metabolism leads to the formation of hydroxylated PCBs (OH-PCBs) and methyl sulfone PCBs (MeSO₂-PCBs). These metabolites are generally more hydrophilic than the parent compound, and therefore are more easily eliminated from the body. However, some congeners have been shown to be strongly retained in human blood, binding to transthyretin with an affinity that is, in general, greater than that of the natural ligand thyroxin itself, which could result in toxicological effects, particularly on the thyroid system. Currently available analytical methods require, in general, extensive sample preparation, which includes a series of time-consuming and low-throughput liquid–liquid and back extractions, evaporations, several cleanup steps, and in some cases, derivatization prior to analysis by gas chromatography (GC) or liquid chromatography (LC) coupled with mass spectrometry (MS). Recent developments in the use of LC coupled with tandem MS (MS/MS) have brought some improvements in terms of sample preparation for the determination of PCB metabolites in blood, although there are still possibilities for continued development. The selected literature has evidenced few studies of LC–MS/MS-based methods, a lack of analytical standards, nonassessment of lower-chlorinated OH-PCBs, and scarce attention to MeSO₂-PCBs in blood. This review aims to evaluate critically the currently available analytical methods for determination of OH-PCBs and MeSO₂-PCBs in blood.     

Analytical methods for the determination of halogens in bioanalytical sciences: a review

Fluorine, chlorine, bromine, and iodine have been studied in biological samples and other related matrices owing to the need to understand the biochemical effects in living organisms. In this review, the works published in last 20 years are covered, and the main topics related to sample preparation methods and analytical techniques commonly used for fluorine, chlorine, bromine, and iodine determination in biological samples, food, drugs, and plants used as food or with medical applications are discussed. The commonest sample preparation methods, as extraction and decomposition using combustion and pyrohydrolysis, are reviewed, as well as spectrometric and electroanalytical techniques, spectrophotometry, total reflection X-ray fluorescence, neutron activation analysis, and separation systems using chromatography and electrophoresis. On this aspect, the main analytical challenges and drawbacks are highlighted. A discussion related to the availability of certified reference materials for evaluation of accuracy is also included, as well as a discussion of the official methods used as references for the determination of halogens in the samples covered in this review.

Analytical investigations on cephalosporins--I: spectrophotometric determination of ceftriaxone

The hydroxylamine-nickel and imidazole-mercury(II) methods for the determination of penicillins and cephalosporins have been adapted to the determination of ceftriaxone both in bulk form and in pharmaceutical formulations.     

Analytical methods for the determination of bisphenol A in food

Food constitutes the primary route for human exposure to bisphenol A (BPA), one of the highest volume chemicals produced worldwide. The estrogenic properties of BPA, its wide dispersive use and the recent extensive literature describing low-dose BPA effects in animals, have raised concerns about its possible adverse effects on human health. A reliable health risk assessment of BPA relies basically on its unambiguous identification and accurate quantification in food, and the aim of the present review is to give an overview of the analytical methods reported so far for the determination of BPA in these matrices. Emphasis is placed on the main strategies developed for sample treatment, which usually consists of several laborious and time-consuming steps in order to achieve the required sensitivity and selectivity. Separation, identification and quantitation of BPA is today reliably made with mass spectrometric methods, namely liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC-MS), and thus main attention is devoted to these techniques, but other methods using LC coupled to fluorescence or electrochemical detection, as well as immunochemical methods are also covered. Recent and expected future developments are discussed.     

Comparison of various techniques for the extraction and determination of antioxidants in plants

The following extraction techniques have been used for extracting antioxidants (apigenin, coumarin, esculetin, umbelliferone, bergapten, quercetin, rutin, scopoletin and xanthotoxin) from plant material: supercritical fluid extraction, pressurized liquid extraction, extraction by means of Soxhlet apparatus, ultrasonic extraction in ultrasonic bath, and by means of ultrasonic probe. The analytical method based on HPLC?UV detection for the determination of selected antioxidants was developed. For all extracts the antioxidant capacity based on the reduction of free 2,2‐diphenyl‐1 ‐picrylhydrazyl radical was also determined. Comparing all results the ultrasonic probe method using 0.75 g of sample extracted by 50 mL of acetonitrile in water (30%, v/v) for 25 min at room temperature and with amplitude at 60% (equal to 90 W) without pulsation was evaluated as the best tool. The most significant indicator demonstrating this statement is the antioxidant capacity expressed as gallic acid equivalent where the ultrasonic probe method showed the best results in 10 of 16 samples. Also the operability of ultrasonic probe extraction method compared to other tested methods is more favorable.     

Analytical aspects of urinary prostaglandin determination

Conclusions The causes of the altered prostaglandin excretion in diabetic ketoacidosis are complex: hypovolaemia, renal hypoperfusion, enhanced diuresis, tubular overload and acidosis. We suggest that the most informative urinary PG determination is that of 13,14-dihydro-15-keto-PGE₂-transformed to bicyclic-PGE₂ by means of the RIA technique.

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Analytische Aspekte der Urinprostaglandinbestimmung

     

Analytical approaches for arsenic determination in air: A critical review

This review describes the different steps involved in the determination of arsenic in air, considering the particulate matter (PM) and the gaseous phase. The review focuses on sampling, sample preparation and instrumental analytical techniques for both total arsenic determination and speciation analysis. The origin, concentration and legislation concerning arsenic in ambient air are also considered. The review intends to describe the procedures for sample collection of total suspended particles (TSP) or particles with a certain diameter expressed in microns (e.g. PM10 and PM2.5), or the collection of the gaseous phase containing gaseous arsenic species. Sample digestion of the collecting media for PM is described, indicating proposed and established procedures that use acids or mixtures of acids aided with different heating procedures. The detection techniques are summarized and compared (ICP-MS, ICP-OES and ET-AAS), as well those techniques capable of direct analysis of the solid sample (PIXE, INAA and XRF). The studies about speciation in PM are also discussed, considering the initial works that employed a cold trap in combination with atomic spectroscopy detectors, or the more recent studies based on chromatography (GC or HPLC) combined with atomic or mass detectors (AFS, ICP-MS and MS). Further trends and challenges about determination of As in air are also addressed.