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Biomedical subjects

S Cavalli

Publications and source records attributed to S Cavalli.

At least 19 recordsLinked to original sources
PubMed2005

Determination of biogenic amines in fresh and processed meat by suppressed ion chromatography-mass spectrometry using a cation-exchange column.

A new method for simultaneous determination of underivatized biogenic amines based on the separation by cation-exchange chromatography and suppressed conductivity coupled with mass spectrometry detection has been developed. The method has been applied to the analysis of cadaverine, putrescine, histamine, agmatine, phenethylamine and spermidine in processed meat products. The amines were extracted from muscle tissue with methanesulfonic acid without any additional derivative step or sample clean-up. Biogenic amines were separated by the IonPac CS17 column, a cation-exchange column used with gradient elution, and detection was done by suppressed conductivity and mass spectrometry. Tyramine was simultaneously analysed by using a spectrophotometer (275 nm) before the suppressed conductivity detection. Linearity of response was obtained in the range 0.25-25 microg mL(-1). The detection limits ranged from 23 microg L(-1) for putrescine to 155 microg L(-1) for spermidine (suppressed conductivity) and from 9 microg L(-1) for agmatine to 34 microg L(-1) for spermidine (MS). Average recoveries from meat samples ranged from 85 to 97% and coefficients of variation ranged from 4.5 to 9.7%. The analysis of biogenic amines in fresh and processed meats (dry-cured, cooked and fermented products) can be used as a quality marker of raw material and for studying the relationship between their changes and the fermentation process involved in dry sausage ripening.

Animals↗
PubMed2004

Determination of acrylamide in drinking water by large-volume direct injection and ion-exclusion chromatography-mass spectrometry.

Acrylamide, a known neurotoxin and putative human carcinogen, has been included among the substances to be monitored in drinking water according to the European Union Directive 98/83 on potable water. This paper reports a new method based on the combination of ion-exclusion chromatographic separation and MS detection. Samples of drinking water have been directly injected in the microbore ICE-AS1 column and detected in the selected-ion monitoring mode by a single quadrupole system with electrospray ionization. Chromatographic conditions, such as eluent composition and flow rate, have been optimized by a central composite design experiment. Statistical analysis of data showed that the amount of acetonitrile fraction in the eluent mixture, composed by acetonitrile and formic acid solution, is the variable that most influences retention of the acrylamide peak. After optimization of MS detection parameters, this method has been validated for spiked drinking water samples. The effect of large-volume injection (up to 500 microl) has been also explored. Linearity was evaluated from 0.5 to 5 microg l(-1). Repeatability, expressed as R.S.D., was 16 and 12% at 0.5 and 1 microg l(-1) respectively. The limit of detection was 0.20 ppb with 500 microl injection volume.

Acrylamide↗
PubMed2003

Ion chromatography with inductively coupled plasma mass spectrometry, a powerful analytical tool for complex matrices estimation of Pt and Pd in environmental samples.

A new method for palladium and platinum direct determination in environmental samples is proposed by coupling ion chromatography with quadrupole inductively coupled plasma MS. In order to optimise Pd and Pt separation and to minimise interference from matrix in real samples, several anionic and cationic stationary phases have been compared at different mobile phase compositions. In particular, the effect of acidity and of the addition of oxalic acid to the eluent on separation and detection performance has been studied, and the anion-exchange column AG11 turned out to be more suitable. After chromatographic and mass spectrometer parameter optimisation, several potential interferences and the main quality parameters of the method, according to the Eurachem-CITAC recommendations, were evaluated: the detection limit for Pt was 5 ng l(-1) while the value for Pd was 230 ng l(-1). The method was successfully employed in the determination of platinum group elements in urban road dust and atmospheric particulates and the complete absence of matrix spectral interferences was demonstrated.

Anions↗
PubMed2001

Recovery of 4-nonylphenol and 4-nonylphenol ethoxylates from river sediments by pressurised liquid extraction.

The pressurised liquid extraction (PLE) of 4-nonylphenol (4-NP) with methanol (100 degrees C and 100 atm) from river sediments was compared with methanolic Soxhlet extraction, the standard method for the sediment analysis. The PLE method showed a precision (average RSD ranged from 6 to 33%) and an accuracy (average recovery 85 and 87% for 4-NP and 4-NPE, respectively) comparable to those of Soxhlet. The extraction was performed on river sediments and no organic carbon content influence was found. The comparative study presented in this paper demonstrates that PLE is an alternative suitable extraction method for 4-nonylphenol and 4-nonylphenol ethoxylate determination in sediments.

Chromatography, Liquid↗
PubMed2001

Ion-chromatographic screening method for monitoring arsenate and other anionic pollutants in ground waters of Northern Italy.

A novel, rapid ion-chromatographic method for screening anionic pollutants in ground water, based on both conductivity and postcolumn spectrophotometric detection, has been developed. A relatively rapid separation of more than ten inorganic and polarizable anions was achieved by coupling an high capacity, hydroxide selective anion-exchange columns (Dionex IonPac AS16) supplied with an electrolytic eluent generator operating in gradient mode. The good control of the selectivity allowed the determination of polarizable anions including arsenate, thiocyanate, thiosulfate and perchlorate without interference from major components present at levels greater than 100 mg l(-1). This method was applied to the determination of arsenate in ground water samples collected in industrial and agricultural zones of Lombardia (Northern Italy). No traces of arsenate were detected in any sample, but added arsenate cannot be revealed by chromatographic analyses. This fact can be attributed to different causes, from reduction to the more reduced arsenic form to precipitation or dissolution in organic or inorganic based colloids. Oxidation with hydrogen peroxide seems to be useful for a partial recovery of added arsenate, but a stronger oxidation method, compatible with chromatographic separation, must be studied.

Anions↗
PubMed2001

Accelerated solvent extraction and liquid chromatography-tandem mass spectrometry quantitation of corticosteroid residues in bovine liver.

A new method for the rapid extraction and unequivocal confirmation of two highly potent fluorinated synthetic corticosteroids, dexamethasone and its beta-epimer betamethasone, in bovine liver was developed. Flumethasone was used as internal standard. An extraction procedure using an accelerated solvent extraction system was employed for the isolation of the analytes in liver samples. The procedure was highly automated, including defatting and extraction steps, sequentially carried out under 1.0 x 10(4) kPa in about 35 min. The extracts were then directly analysed by tandem mass spectrometry with on-line liquid chromatography. The analytes were ionised in a heated nebulizer interface operating in the negative ion mode where the molecular related ions [M-H-CH2O]- were generated for each analyte, at m/z 361 for betamethasone and dexamethasone and at m/z 379 for flumethasone. They served as precursor ions for collision-induced dissociation and three diagnostic product ions for the drugs were identified to carry out analyte confirmation by selected reaction monitoring. Assessment of recovery, specificity and precision for betamethasone, dexamethasone and flumethasone proved the method suitable for confirmatory purposes. The limit of quantification of betamethasone and dexamethasone in liver tissue was 1.0 microg/kg.

Animals↗
PubMed1999

Ion chromatography determination of trace level bromate by large volume injection with conductivity and spectrophotometric detection after post column derivatisation.

Bromate is a well known by-product produced by the ozonisation of drinking water; the allowed concentration for human consumption has to be regulated to the low microg l(-1) range. A direct injection, ion chromatographic method was developed using a tetraborate eluent with serially connected conductivity and spectrophotometric detection. Bromate was detected after post-column reaction with fuchsin at 520 nm. Sample capacity was investigated by injecting large volumes (up to 6 ml) using a high total hardness and chloride tap water. Linear correlation of bromate response with volumes from 1 ml to 6 ml was demonstrated, the main limitation being the overlapping of the chloride peak with bromate. Up to 1.5 ml sample can be injected without any pre-treatment. With more than 1.5 ml injection volume, a sample pre-treatment with a cartridge in Ag and H form, followed by a 10 min degassing in an ultrasonic bath, was needed. This method was validated by analysing secondary reference materials and real samples from a drinking water treatment plant. The method was linear from the limit of quantification to 20 microg l(-1). Reproducibilities in tap water were 18% (5 microg l(-1), n=12) and 21% (1 microg l(-1), n=4) respectively for 1.5 and 6 ml injection volumes with conductivity detection, and 17% at 0.5 microg l(-1) (n=9) with spectrophotometric detection. Calculated detection limits were 0.5 microg l(-1) (6 ml) ahd 2 microg l(-1) (1.5 ml) for conductivity detection and 0.3 microg l(-1) (1.5 ml) for spectrophotometric detection.

Bromates↗
PubMed1999

Matrix effects in the determination of bromate in drinking water by ion chromatography.

Bromate is a well known by-product produced by the ozonation of drinking water; the allowed concentration for human consumption has to be regulated to low microgram l-1 range. By using a high-capacity anion-exchange column, it should be possible to determine bromate at this low concentration by direct injection of a very large volume (up to 1 ml) without any sample preconcentration and pretreatment. The feasibility of this technique for the determination of bromate in drinking water has been explored in our work. The experimental results showed that matrix effect, due to inorganic ions contained in drinking water, strongly influenced the chromatographic behaviour of the bromate peak. The increase of the total ion content led to a correlated decrease in the efficiency of the analyte peak so that effective detection limits depended on the matrix composition. In this work chromatographic parameters (efficiency, asymmetry and resolution) of bromate peak are discussed in relation to the concentration of the main inorganic anions, and the injection volume (from 250 microliters to 1 ml).

Bromates↗
PubMed1999

Determination of transition metals in wine by IC, DPASV-DPCSV, and ZGFAAS coupled with UV photolysis.

In the present work ion chromatography (IC), differential pulse anodic (DPASV) or cathodic stripping voltammetry (DPCSV), and Zeeman graphite furnace atomic absorption spectroscopy (ZGFAAS) were applied to the determination of heavy and transition metals in wine. The matrix is degraded by oxidative UV photolysis in a digester equipped with a high-pressure mercury lamp. The temperature of the sample is maintained at 85 +/- 5 degrees C by a combined air/water cooling system. This procedure has decisive advantages if compared with other sample pretreatment techniques. Most organic wine constituents degrade in <1 h, whereas metals quantitation remains unaffected by UV radiation, with the exception of manganese. The clear solution is directly analyzed for most common heavy and transition metals such as cadmium, cobalt, copper, iron, lead, nickel, and zinc. In the absence of standards, the results obtained by different techniques are compared and are found in good agreement. All of the considered techniques appear to be equivalent, but ZGFAAS is more time-consuming because it does not permit multielement analyses.

Chromatography↗
PubMed1998

Improved ion chromatography-integrated pulsed amperometric detection method for the evaluation of biogenic amines in food of vegetable or animal origin and in fermented foods.

An improved method for the simultaneous determination of underivatized biogenic amines, cadaverine, putrescine, spermidine, histamine, tyramine and some amino acids precursors, histidine and tyrosine, in food products, based on ion-exchange chromatography (IC) with integrated pulsed amperometric detection (IPAD) has been developed. The method was successfully used for the analysis of biogenic amines and amino acids in food both of vegetable (kiwi, Actinidia chinensis) and animal origin, (fish, pilchard), as well as in fermented foods, such as cheese (Emmenthal) and dry sausages (salami). The method was also successfully used to study the changes in biogenic amines during the ripening of dry fermented sausages (salami). The analytes were extracted from foods with perchloric acid and the extracts were purified by liquid-liquid partition using n-hexane. Determination of biogenic amines was performed through cation-exchange chromatography with isocratic elution and IPAD. The detection limits for the analytes under investigation were found to range from 1.25 to 2.50 ng, at a signal-to-noise ratio of 3:1. Average recoveries ranged from 85.5 to 97.4% and R.S.D. values ranged from 3.4 to 8.8. The proposed method offers a number of advantages over our previous IPAD method, such as the application to a larger number of analytes and matrices, a simpler extraction procedure and clean-up, isocratic elution using low acid and base concentrations, an improved chromatographic separation and a lower detection limit.

Animals↗
PubMed1997

State-of-the-art ion chromatographic determination of inorganic ions in food.

A review of the applications of ion chromatography (IC) to the determination of inorganic ions in food is presented. The most promising sample preparation techniques, such as accelerated solvent extraction, supercritical fluid extraction, solid-phase extraction, UV photolysis, microwave-oven digestion and pyrohydrolysis are discussed. Among the various inorganic anions, nitrogen, sulphur and phosphorus species and halides are widely determined in foods and to a lesser extent only, cyanide, carbonate, arsenic and selenium species are considered. IC determination of inorganic cations deals with ammonium ion, alkali, alkaline-earth, heavy and transition metals particularly and only a small amount of literature is found on the other ones, like aluminium and plantinum. A particular advantage of IC over traditional techniques is the simultaneous determination of several species.

Anions↗
PubMed1997

Use of ion chromatography for monitoring microbial spoilage in the fruit juice industry.

Fruit juices and purees are defined as fermentable, but unfermented, products obtained by mechanical processing of fresh fruits. The presence of undesired metabolites derived from microbial growth can arise from the use of unsuitable fruit or from defects in the production line or subsequent contamination. This involves a loss in the overall quality that cannot be resolved by thermal treatment following the start of fermentation. With these considerations, together with microbiological control, the analysis of different metabolites, which can be considered as microbial growth markers, such as alcohols (i.e. ethanol, etc.), acids (i.e. acetic, fumaric, lactic, etc.) is fundamental in order to achieve a better evaluation of product quality. Enzymatic determination and other single-component analytical techniques are often used for the determination of these metabolites. When the microbial spoilage is not well known, this results in a long and cumbersome procedure. A versatile technique that is capable of determining many metabolites in one analysis could be helpful in improving routine quality control. For this purpose, an ion chromatographic technique, such as ion exclusion, for separation, and diode array spectrophotometry and conductivity, for detection, were evaluated. Both different industrial samples and inoculated samples were analyzed.

Acetic Acid↗
PubMed1997

[Cystadenocarcinoma of the pancreas. Case report and review of the literature].

Pancreatic cystadenocarcinoma is a quite rare neoplasm. Due to the low incidence and recent nosographic arrangement, the natural evolution and the clinical development of this type of neoplasm are not well known. The Authors report their experience and a review of the Literature trying to establish the criteria for the classification, diagnosis and therapy of pancreatic cystadenocarcinoma.

Aged↗
PubMed1997

[Aneurysm of the hepatic artery. Case report and review of the literature].

Hepatic artery aneurysms (HAAs) are considered rare even though their reports in the literature are becoming more and more frequent. The great improvement in the diagnosis of vascular diseases and the increasing incidence of atherosclerosis have resulted in a wider recognition of these pathologies. Differently from other splanchnic locations HAAs have a high risk of rupture (up to 80%) so that an aggressive treatment is required. Different therapeutic options are currently available: simple ligation of the artery, aneurysm excision and vascular reconstruction, transcatheter embolization. However, the therapeutic choice must be evaluated in each single case, depending on the size, aspect and locations of the aneurysm, and requiring an accurate study of the collateral vascular supply. Finally, since additional aneurysms in other sites are frequent, a dose follow up of these patients is recommended.

Aged↗
PubMed1995

Direct determination of seleno-amino acids in biological tissues by anion-exchange separation and electrochemical detection.

Several studies have described the determination of selenium in protein extracts from tissues of marine or terrestrial animals, but have not identified the different chemical forms of selenium that are present. Selenium may be present as seleno-amino acids. Selenocysteine, for example, is a normal component of glutathione peroxidase, an antioxidant enzyme which may behave like other antioxidants, such as vitamin E, protecting tissues against methylmercury toxicity. The present study illustrates a method for the characterization of seleno-amino acids, such as selenocysteine and selenomethionine, in proteins extracted from the liver of marine mammals. The mechanism of detoxification of methylmercury, which involves seleno-compounds, is identified. The analytical determination was carried out using high-performance anion-exchange chromatography coupled with integrated pulsed amperometric detection (HPAEC-IPAD). This method allows the direct determination of underivatized amino acids, eliminating the procedure of pre- or postcolumn derivatization. The chromatographic separation was carried out on an anion-exchange column using a quaternary gradient elution. In order to optimize this method, interferences of amino acids and the influence of pH and ionic strength on the separation and electrochemical detection were studied. The IPAD response for the direct detection of amino acids is optimum at pH > 11. The detection limit (S/N = 3) for selenocysteine was found to be 450 micrograms/l. The application of this method for the identification of seleno-amino acids in protein hydrolysates is also shown.

Animals↗
PubMed1990

[Mechanical staplers. Our experience].

The Authors report their experience concerning 237 stapled sutures performed during 93 gastro-intestinal operations. Intraoperative technical advantages are described and improved postoperative courses are outlined; in particular earlier recovery of intestinal function, minimal rate of complications and 11-day average post-operative stay are reported.

Adolescent↗