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Carlo G Zambonin

Publications and source records attributed to Carlo G Zambonin.

13 recordsLinked to original sources
PubMed2006

Profiling urinary metabolites of naproxen by liquid chromatography-electrospray mass spectrometry.

Glucuronidation, an important metabolic process for the biotransformation of drugs into easily eliminable water-soluble detoxification products, can also lead to biologically active or toxic glucuronide conjugates. The present work describes a liquid chromatography-electrospray mass spectrometry (LC-ESI-MS) approach for the characterization of naproxen and O-6-desmethylnaproxen glucuronides. The method is fast and efficient and permitted to individuate alpha and beta isomers of both naproxen and O-6-desmethylnaproxen glucuronides. The procedure could be potentially extended to the characterization of other drug metabolites.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2006

Determination of Ochratoxin A in wine at sub ng/mL levels by solid-phase microextraction coupled to liquid chromatography with fluorescence detection.

Solid-phase microextraction (SPME), using a polydimethylsiloxane/divinylbenzene (PDMS/DVB) fiber, interfaced with liquid chromatography-fluorescence detection (LC-FD) has been applied to the determination of Ochratoxin A (OTA) in wine samples. Compared to the most widely adopted extraction/clean-up procedure based on immunoaffinity columns (IAC), the solventless extraction is simpler and cost-effective, requiring the simple immersion of the fiber in diluted wine samples. Furthermore, a fast LC separation is achieved under isocratic conditions. The linear range investigated in wine was 0.25-8 ng/mL; at fortification levels of 0.5 and 2 ng/mL, within-day intra-laboratory precision (repeatability) values, expressed as RSD%, were 5.9 and 5.1, respectively, whereas between days (n = 4) precision was 8.5 and 7.1%, respectively. The limit of detection (LOD) at a signal-to-noise (S/N) ratio of 3 was 0.07 ng/mL; the limit of quantification (LOQ) calculated at S/N = 10 was 0.22 ng/mL, well below the European regulatory level of 2 ng/mL. The potential of the method has been demonstrated by the analysis of a number of different wine samples.

Chemical Fractionation↗
PubMed2006

Ochratoxin a determination in beer by solid-phase microextraction coupled to liquid chromatography with fluorescence detection: a fast and sensitive method for assessment of noncompliance to legal limits.

A solid-phase microextraction-liquid chromatography-fluorescence detection (SPME-LC-FD) method for the determination of ochratoxin A (OTA) in commercial beer samples was developed for the first time using a 60 microm thick poly(dimethylsiloxane)/divinylbenzene (PDMS/DVB) fiber. The procedure required a very simple sample pretreatment, an isocratic elution, and provides a selective extraction. All of the factors influencing fiber adsorption (extraction time, temperature, pH, and salt addition) and desorption of the analyte (desorption and injection time and desorption solvent mixture composition) have been investigated. The linear range investigated in beer was 0.03-2 ng/mL; within-day and between-days relative standard deviation in beer were 4.3 and 5.9%, respectively. The limit of quantification in spiked beer was 53 pg mL(-)(1), well below all European regulatory levels.

Beer↗
PubMed2005

Determination of naproxen in human urine by solid-phase microextraction coupled to liquid chromatography.

An SPME-LC-UV method for the determination of the non-steroidal anti-inflammatory drug (NSAID) naproxen and, after hydrolysis, its glucuronide in human urine samples was developed for the first time using a carbowax/templated resin (CW/TPR-100)-coated fibre. The procedure required a very simple sample pre-treatment, an isocratic elution, and provides a highly selective extraction. All the aspects influencing adsorption (extraction time, temperature, pH and salt addition) and desorption (desorption and injection time and desorption solvent mixture composition) of the analyte on the fibre have been investigated. The linear range investigated in urine was 0.2-20 microg/ml (that covers the typical naproxen urinary concentration) and almost quantitative recoveries were obtained. Within-day and between-days R.S.D.% in urine were 4.5 and 6.0, respectively. The LOD and LOQ in spiked urine were 0.03 and 0.20 microg/ml, well below the usual naproxen urinary level.

Adsorption↗
PubMed2005

Laser desorption/ionization time-of-flight mass spectrometry of triacylglycerols in oils.

Selected triacylglycerols (TAGs) were directly analyzed on a standard stainless steel target plate by laser desorption/ionization time-of-flight mass spectrometry (LDI-TOFMS). Sodium and potassium ion adducts of TAGs were produced, and the thermal desorption/ionization mechanism was invoked to rationalize the experimental observations. The method permits a simple and fast qualitative analysis of TAGs. Advantages of this approach relative to matrix-assisted laser desorption/ionization (MALDI) are simpler sample preparation, lack of need to use a matrix with consequent absence of matrix interference peaks in the spectra, and potential improvements in shot-to-shot reproducibility due to the absence of the crystallization step resulting in a more homogenously deposited sample. The procedure was successfully applied to the determination of TAGs in whole oils, yielding very fast TAG fingerprints.

Plant Oils↗
PubMed2004

Determination of methylxanthines in urine by liquid chromatography with diode array UV detection.

A liquid chromatography-diode array UV detection (LC-UVDAD) method for the simultaneous determination of four methylxanthines (caffeine, theobromine, paraxanthine and theophylline) is described. The chromatographic separation was achieved on a LC-18-DB column using 20:80 methanol:buffer (5mM citric acid adjusted to pH 5 with triethylamine) as mobile phase. The method has been applied to urine samples. The overall procedure had % recoveries ranging from 81.6 +/- 2.6 (theophylline) to 99.3 +/- 6.3 (theobromine). The within-day (n = 5) and between-days (n = 5 over 5 days) coefficients of variation in urine ranged from 2.9% (theophylline) to 3.4% (theobromine) and from 5.2% (theophylline) to 6.2% (theobromine). Estimated LOD and LOQ in urine ranged from 0.15microg/ml (theophylline) to 0.3microg/ml (theobromine) and from 0.8microg/ml (theophylline) to 1.2microg/ml (theobromine), respectively. Urine samples naturally contaminated with the target analytes were found.

Chromatography, Liquid↗
PubMed2004

Simultaneous determination of free mycophenolic acid and its glucuronide in serum of patients under mycophenolate mophetil therapy by ion-pair reversed-phase liquid chromatography with diode array UV detection.

An high performance liquid chromatography (HPLC)-UV method for the simultaneous determination of the free forms of mycophenolic acid (MPA) and its phenol glucuronide (MPAG) in human serum samples was developed for the first time. Chromatographic separation was performed on octadecylsilane based stationary phase in combination with a mobile phase of methanol/buffered tetrabutylammonium (TBA) salt mixture. Sample pretreatment consisted of an ultrafiltration step followed by clean-up/enrichment on a C(18) solid-phase extraction (SPE) cartridge. Average recoveries of (99.7 +/- 0.2)% and (64.1 +/- 6.9)% for free MPA and MPAG, respectively, were estimated in the concentration range from 0.5 to 10 microg/ml. The within-day and between-days coefficients of variation were 0.4 and 0.8% for free MPA (0.1 microg/ml spiking level) and 0.8 and 1.6% for free MPAG (5 microg/ml spiking level), respectively. The linear ranges for free MPA and MPAG were 0.06-1 and 0.2-10microg/ml, respectively. Detection limits of 4 and 17 ng/ml for free MPA and MPAG were estimated in spiked serum. The same HPLC method was also capable of a simultaneous determination of the total concentration of MPA and MPAG when coupled to a proper sample pretreatment step. The potential of the method is demonstrated by excretion kinetics measurement in serum of patients receiving MMF therapy.

Algorithms↗
PubMed2004

Determination of the immunosuppressant mycophenolic acid in human serum by solid-phase microextraction coupled to liquid chromatography.

A solid phase microextraction (SPME)-HPLC-UV method for the determination of the immunosuppressant mycophenolic acid (MPA) in human serum samples was developed for the first time. The procedure, that employed a carbowax/templated resin (Carbowax/TPR-100) as fiber coating, required a very simple sample pretreatment, an isocratic elution, and provides an highly selective extraction. The linear range was 0.2-100 microg x ml(-1). Recovery was practically unchanged (63+/- 4%) passing from 0.2 to 100 microg x ml(-1) level. Within-day and between-days coefficient of variation ranged from 5.9 to 6.5% and from 8.8 to 9.2%, respectively. A detection limit of 0.05 microg x ml(-1) was estimated in spiked serum. The method was successfully applied to the determination of MPA in serum of a patient under mycophenolate mophetil ester (MMF) therapy, as demonstrated by the relevant concentration-time profiles.

Chromatography, High Pressure Liquid↗
PubMed2003

Simultaneous determination of ochratoxin A and cyclopiazonic, mycophenolic, and tenuazonic acids in cornflakes by solid-phase microextraction coupled to high-performance liquid chromatography.

A solid-phase microextraction (SPME) method, coupled to liquid chromatography with diode array UV detection (LC-UV/DAD), for the simultaneous determination of cyclopiazonic acid, mycophenolic acid, tenuazonic acid, and ochratoxin A is described. Chromatographic separation was achieved on a propylamino-bonded silica gel stationary phase using acetonitrile/methanol/ammonium acetate buffer mixture (78:2:20, v/v/v) as mobile phase. SPME adsorption and desorption conditions were optimized using a silica fiber coated with a 60 microm thick polydimethylsiloxane/divinylbenzene film. Estimated limits of detection and limits of quantitation ranged from 3 to 12 ng/mL and from 7 to 29 ng/mL, respectively. The method has been applied to cornflake samples. Samples were subjected to a preliminary short sonication in MeOH/2% KHCO(3) (70:30, v/v); the mixture was evaporated to near dryness and reconstituted in 1.5 mL of 5 mM phosphate buffer (pH 3) for SPME followed by LC-UV/DAD. The overall procedure had recoveries (evaluated on samples spiked at 200 ng/g level) ranging from 74 +/- 4 to 103 +/- 9%. Samples naturally contaminated with cyclopiazonic and tenuazonic acids were found; estimated concentrations were 72 +/- 9 and 25 +/- 6 ng/g, respectively.

Chromatography, High Pressure Liquid↗
PubMed2002

Coupling solid-phase microextraction to liquid chromatography. A review.

Solid-phase microextraction (SPME) is a technique for extraction of organic compounds from gaseous, aqueous, and solid matrices. SPME is rapid and simple, ideal for automation and for in situ measurements, and no harmful solvents are needed. The principle of SPME involves equilibration of the analytes between the sample matrix and an organic polymeric phase coated on a fused-silica fiber. SPME is traditionally combined with analysis by gas chromatography (GC) and this combination has proved sensitive, accurate, and precise for quantitative analysis of different classes of volatile compound. More recently SPME has been coupled with liquid chromatography to widen its range of application to non-volatile and thermally unstable compounds also. This article reviews the status of SPME coupled with liquid chromatography. It focuses on different applications of the technique, e.g. environmental samples, biological fluids, and food samples, to show that SPME-HPLC has great potential in the analysis of a wide range of compounds in different matrices.

Journal Article↗
PubMed2002

SPME-LC with UV detection to study delorazepam-serum albumin interactions.

Solid phase microextraction coupled to high performance liquid chromatography with UV detection (SPME/LC-UV) has been employed to study the binding of delorazepam to human serum albumin (HSA) and bovine serum albumin (BSA). The procedure could also be potentially extended to the measurement of partition coefficients between a wide variety of semi- or non-volatile compounds and matrices. The method is solvent free, simple, fast, and drawbacks of the conventional analytical techniques are avoided. Moreover, the matrix did not interfere with the measurement by binding to the fibre and the amount extracted by the fibre was negligibly small; thus it did not disturb the delorazepam-protein binding.

Anti-Anxiety Agents↗
PubMed2002

LC-ion trap electrospray MS-MS for the determination of cyclopiazonic acid in milk samples.

An LC-ESI-MS (negative ions) method was developed for the determination of cyclopiazonic acid (CPA), a mycotoxin produced by many Aspergillus and Penicillium genuses, in milk samples. First, the acquisition parameters of the ESI mass spectrometer were optimised for deprotonated CPA and MS-MS measurements were performed, giving a fragmentation pattern. After this stage, LC separation was applied to milk extracts (with or without CPA spikes) by means of an aminic column, using the selective reaction monitoring (SRM) acquisition mode for MS detection. The CPA response was linear over three decades of concentration and an LOD of 5 ng mL(-1) was estimated; moreover, the extraction procedure produced almost quantitative recoveries of CPA from milk. Twenty different milk samples were analysed and three of them were found to be contaminated with CPA to various extents.

Animals↗