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ABSTRACT: In the dairy industry one of the most common frauds is mixing high-value milk (sheep's and goats') with milk of lower value (cows'). This illegal practice has commercial, ethical, and serious sanitary consequences because consumers can be exposed to hidden allergens contained in the undeclared cows' milk. Here, we investigated the possibility of using matrix-assisted laser-desorption/ionization (MALDI)-time of flight (TOF) mass spectrometry (MS) as a rapid, sensitive, and accurate technique for detection of milk adulteration by analysis of phospholipid profiles. Lipid extracts of pure raw milk, commercial milk, and binary mixtures of cows' and goats' milk and cows' and sheep's milk (the concentrations of each milk varied from 0 % to 50 %) were analyzed with α-cyano-4-chlorocinnamic acid as matrix. The abundance ratio of the ions at m/z 703 and m/z 706 was found to be species-correlated and was used as marker of cows' milk in sheep's and goats' milk. Furthermore, the procedure could potentially be applied to cheese samples, because peaks at m/z 703 and 706 were also found in several commercial cheese samples. This approach proved to be an efficient, rapid, and inexpensive method of detecting milk fraud.
Analytical and Bioanalytical Chemistry 12/2012; · 3.78 Impact Factor
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ABSTRACT: The adulteration of extra virgin olive oil (EVOO) with hazelnut oil (HO) is frequent and constitutes a serious concern both for oil suppliers and consumers. The high degree of similarity between the two oils as regards triacylglycerol, total sterol and fatty acid profile, complicates the detection of low percentages of HO in EVOO. However, phospholipids (PLs) are usually present in seed oils at a concentration range of 10-20g/kg, while the amounts of PLs in VOOs are 300-400 times lower. Thus, in this work a sample pretreatment procedure focused towards the selective PLs extraction was developed; the Bligh-Dyer extraction procedure was modified introducing the ionic liquid resulting from the combination of TBA (tributylamine) and CHCA (α-Cyano-4-hydroxycinnamic acid) as extraction solvent. The selective extraction and enrichment of phospholipids from EVOO and HO samples was then achieved. The relevant extracts were analyzed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) using the same ionic liquid TBA-CHCA as MALDI matrix, that was found to be very suitable for PLs analysis. In fact, a remarkable increase of the phospholipids signals, with a simultaneous decrease of those relevant to triacylglycerols and diacylglycerols, was observed in the relevant mass spectra. The applicability of the whole method to the individuation of the presence of HO in EVOO was demonstrated by the analysis of EVOO samples progressively adulterated with variable quantities of HO, that was still detectable at a 1% contamination level.
Food Chemistry 09/2012; 134(2):1192-8. · 3.65 Impact Factor
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Caterina Foti,
Elisabetta Damiani, Carlo G Zambonin,
Nicoletta Cassano,
Eustachio Nettis,
Antonio Ferrannini,
Cosima D Calvano,
Antonella Aresta,
Paolo Romita,
Anna M Aloia,
Gino A Vena
Annals of allergy, asthma & immunology: official publication of the American College of Allergy, Asthma, & Immunology 01/2012; 108(1):60-1. · 2.83 Impact Factor
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ABSTRACT: A method of direct lipid analysis by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) in intact membranes, without prior extraction/separation steps, is described. Here, we demonstrate the efficacy of a strong base, 1,8-bis(dimethylamino)naphthalene (DMAN; proton sponge), as a novel matrix for MALDI-time-of-flight (TOF) MS analysis of whole cell bacteria. Initially, individual acidic low-molecular-weight analytes such as standard free fatty acids and phospholipids were analyzed using DMAN as matrix. Clear negative-mode MALDI-TOF MS spectra of all analytes show only deprotonated analyte signals at a low picomole limit of detection with the complete absence of matrix-related signals. These results indicate that DMAN represents a suitable matrix for MALDI-TOF MS analysis of mixtures of complex lipids as the intact membranes of microorganisms. DMAN was successfully applied to the analysis of Lactobacillus sanfranciscensis and L. plantarum microorganisms. Different components were sensitively detected in a single spot, including 16:0, 18:2, 18:3, and 21:0 free acids, glycolipids, phosphatidylglycerols (PGs) and cardiolipins. This method might be of general application, offering the advantage of quickly gaining information about lipid components of other gram-positive bacterial membranes.
Rapid Communications in Mass Spectrometry 06/2011; 25(12):1757-64. · 2.79 Impact Factor
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ABSTRACT: The oil polar fraction may have a great potential for the characterization of vegetable oils and for the individuation of adulterations. In particular, adulteration of extra-virgin olive oil (EVOO) with hazelnut oil (HO) is one of the most difficult ones to detect due to the similar composition as regards triacylglycerol, total sterol and fatty acid profile. A new micro-solid phase extraction (µ-SPE) procedure based on hydrophilic liquid chromatography (HILIC) micro-columns was developed for the selective extraction and enrichment of polar compounds from EVOO and HO before matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-ToF-MS) analysis. The method permits a simple and fast qualitative analysis of the polar fraction of the oils under study; furthermore, some peaks (such as the m/z ions 496.39, 520.46 and 522.47) were found to be present only in HO, indicating that they could be diagnostic for the presence of HO in EVOO. In order to verify the potential of the method for the individuation of this adulteration, EVOO was progressively adulterated with variable quantities of HO, subjected to the HILIC enrichment and finally to MALDI-ToF-MS analysis; the detection of adulteration was possible up to the level of 5%. Eventually, diagnostic polar compounds were identified as lysophosphatidylcholine (LPC) (16:0/0:0), LPC (18:2/0:0), LPC (18:1/0:0) by means of capillary liquid chromatography-electrospray ionization-quadrupole-ToF-MS (CapLC-ESI-Q-ToF-MS) analysis.
Biological Mass Spectrometry 09/2010; 45(9):981-8. · 3.41 Impact Factor
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ABSTRACT: Cod liver oil is a well-known "nutraceutical", which contains a wide range of substances, including triacylglycerols (TAGs), mono- and di-acylglycerols, free fatty acids, vitamins and n-3 polyunsaturated fatty acids. Topically applied, cod liver oil contributes to faster wound healing and improvement in skin quality. We recently reported a case of allergic contact dermatitis to cod liver oil contained in a topical ointment, in whom the patch test reaction with the ointment containing cod liver oil at a concentration of 40% was stronger than the reaction induced by a pure cod liver oil at the same concentration. We hypothesized that the different reactivity could be explained by differences in composition of the two products. In order to verify this hypothesis, we assessed the composition of those products using a matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). The results obtained showed that the spectra of the ointment and of the cod liver oil samples were very similar, even if a major number of peaks were observable in the higher mass range of the spectra relevant to the analysis of the ointment sample, that have been assigned to higher molecular weight TAGs. Our results suggest that the different reactivity to the two products could be due to differences in the amount of contained TAGs. TAGs may favor the penetration of the allergen(s) or may be the direct culprit substances, taking into account that TAGs have been reported to have sensitizing properties.
Food and Chemical Toxicology 10/2008; 46(12):3580-5. · 3.00 Impact Factor
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ABSTRACT: Protein glycosylation is a common post-translational modification that is involved in many biological processes, including cell adhesion, protein-protein and receptor-ligand interactions. The glycoproteome constitutes a source for identification of disease biomarkers since altered protein glycosylation profiles are associated with certain human ailments. Glycoprotein analysis by mass spectrometry of biological samples, such as blood serum, is hampered by sample complexity and the low concentration of the potentially informative glycopeptides and -proteins. We assessed the utility of lectin-based and HILIC-based affinity enrichment techniques, alone or in combination, for preparation of glycoproteins and glycopeptides for subsequent analysis by MALDI and ESI mass spectrometry. The methods were successfully applied to human serum samples and a total of 86 N-glycosylation sites in 45 proteins were identified using a mixture of three immobilized lectins for consecutive glycoprotein enrichment and glycopeptide enrichment. The combination of lectin affinity enrichment of glycoproteins and subsequent HILIC enrichment of tryptic glycopeptides identified 81 N-glycosylation sites in 44 proteins. A total of 63 glycosylation sites in 38 proteins were identified by both methods, demonstrating distinct differences and complementarity. Serial application of custom-made microcolumns of mixed, immobilized lectins proved efficient for recovery and analysis of glycopeptides from serum samples of breast cancer patients and healthy individuals to assess glycosylation site frequencies.
Journal of Proteomics 08/2008; 71(3):304-17. · 4.88 Impact Factor
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ABSTRACT: A new method for the determination of Ochratoxin A (OTA) in green coffee beans by solid-phase microextraction (SPME) coupled to liquid chromatography with fluorescence detection (LC-FD) is described for the first time. Coffee samples were extracted by a 5% NaHCO(3) solution, followed by a clean-up step of the extract by chloroform partition. The aqueous extract was then acidified and finally subjected to SPME-LC-FD analysis. The investigated linear range in coffee was 2-32 ng/g. Within-day RSD% in coffee spiked at 2 and 32 ng/g levels were 3.3 and 2.7, respectively, whereas the between-days RSD% were 4.1 and 3.8, respectively. The limits of detection (LOD) and quantitation (LOQ), calculated at a signal-to-noise ratio of 3 and 10 (noise calculated peak to peak on a blank chromatogram at the OTA retention time), were 0.3 and 2 ng/g, respectively.
Journal of Chromatography 05/2008; 1187(1-2):145-50. · 4.53 Impact Factor
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ABSTRACT: Laser desorption ionization time-of-flight mass spectrometry (LDI-TOF MS) was used to characterize olive and sunflower oils before and after thermally assisted oxidation in order to develop a rapid fingerprinting method for oil that contains unchanged and oxidized components. No matrix was used to assist laser desorption, and simplified mass spectra were obtained in the mass range of interest (m/z 500-1000), where triacyl- and diacylglycerol ions were observed. Sample preparation was reduced to dissolving oil in chloroform saturated with NaCl. Sodiated triacylglycerols (TAGs), their epoxy/hydroxy and hydroperoxy derivatives, as well as TAGs with shortened chain fatty acids (beta-scission products) were clearly observed in the spectra. LDI-TOF MS rapidly provides semiquantitative information about the oxidation level of edible oil, and thus represents a very useful quality control tool.
Analytical and Bioanalytical Chemistry 01/2008; 389(7-8):2075-84. · 3.78 Impact Factor
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ABSTRACT: The low molecular weight (LMW) serum proteome (<15 kDa) is the most generally informative from a medical point of view. Different sample pre-treatment approaches and devices for serum depletion in high-abundant proteins were tested in order to analyze, by MALDI-TOF-MS (both in "linear" and "reflectron" acquisition mode), the serum low molecular weight proteins/peptides. The best results in terms of detected ions number and abundance were obtained by using ultrafiltration of serum on 30 kDa molecular weight cut off membranes followed by miniaturized reverse-phase solid-phase extraction (mu-SPE) as sample pre-treatment; this procedure yielded also satisfactory within-sample and sample-to-sample repeatability (on both m/z values and peak intensity of the main observable ions). The procedure was finally applied to serum samples of breast cancer patients, and the relevant results compared to "normal" samples seem to be promising for the individuation of different profiles ("linear" and "reflectron" mode) and/or peptides capable of differentiating for malignancies ("reflectron" mode).
Journal of Pharmaceutical and Biomedical Analysis 01/2008; 46(1):157-64. · 2.97 Impact Factor
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ABSTRACT: A new method for the determination of ochratoxin A (OTA) in human urine samples has been developed using solid-phase microextraction (SPME) interfaced with liquid chromatography-fluorescence detection (LC-FD). This method is simpler and cheaper compared to the most widely adopted clean-up procedures for OTA extraction from urine (usually based on immunoaffinity columns). Briefly, urine samples, diluted 1:5 with phosphate buffer (10 mM, pH 3), were partitioned against chloroform and the aqueous phase extracted by a polydimethylsiloxane/divinylbenzene (PDMS/DVB) fiber. The fiber was then "statically" desorbed, through a SPME interface, into a LC system operating in isocratic conditions. The linear range investigated in urine was 0.01-1 ng/ml. Within-day R.S.D.% in urine spiked at 0.1 and 1 ng/ml were 3.9 and 1.9, respectively, whereas the between-days R.S.D.% were 5.5 and 3.0, respectively. The limits of detection (LOD) and quantitation (LOQ) calculated at a signal-to-noise ratio of 3 and 10 (noise calculated peak to peak on a blank chromatogram at the OTA retention time) were 0.01 and 0.05 ng/ml, respectively.
Journal of Pharmaceutical and Biomedical Analysis 09/2007; 44(4):1014-8. · 2.97 Impact Factor
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ABSTRACT: Recently, D-limonene-based solvents are used as a safe alternative to xylene for histological and cytological application to dissolve paraffin. We report the case of a histopathology technician with a recalcitrant hand contact dermatitis strictly related to the use of a limonene-based solvent agent. Patch tests with SIDAPA (Italian Society of Allergological, Professional and Environmental Dermatology) standard series, limonene-based solvent used by the patient and D- and L-limonene (both oxidized and nonoxidized form) and with Giemsa and methylene blue stains were performed. Patch testing gave positive results to oxidized D- and L-limonene. The patient retired from work and promptly improved and healed the hand eczema. Subsequently, the potential occurrence of limonene oxidation products in the incriminated preparation was investigated using gas chromatography-mass spectrometry. While patch test showed positive reaction to oxidized limonene, chemical analysis failed to detect oxidized limonene in the preparations used by the patient. Considering the strict relation between the use of the preparations and the appearance of symptoms, we can assume that oxidized limonene may be produced during the handling of limonene-based products, especially in the presence of oxidants stains, frequently used in histological laboratories.
Contact Dermatitis 03/2007; 56(2):109-12. · 3.51 Impact Factor
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ABSTRACT: 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.
Journal of Pharmaceutical and Biomedical Analysis 07/2006; 41(4):1312-6. · 2.97 Impact Factor
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ABSTRACT: 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.
Journal of Chromatography 06/2006; 1115(1-2):196-201. · 4.53 Impact Factor
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ABSTRACT: 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.
Journal of Agricultural and Food Chemistry 04/2006; 54(5):1594-8. · 2.82 Impact Factor
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Rapid Communications in Mass Spectrometry 02/2006; 20(2):325-7. · 2.79 Impact Factor
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ABSTRACT: 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.
Journal of Pharmaceutical and Biomedical Analysis 10/2005; 39(3-4):643-7. · 2.97 Impact Factor
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ABSTRACT: HS-SPME-GC-MS in combination with PCA was employed to discriminate different arabica/robusta blends having different geographical origins. HS-SPME confirmed to be an effective and reproducible sampling technique for routine characterization of coffees. In addition, the chemometric approach permitted to find parameters suitable for the differentiation of the different blends and the determination of the real quality of the products. Finally, the proposed methods have been successfully applied to some commercial coffee blends.
Talanta 04/2005; 66(1):261-5. · 3.79 Impact Factor
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ABSTRACT: 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.
Rapid Communications in Mass Spectrometry 02/2005; 19(10):1315-20. · 2.79 Impact Factor
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ABSTRACT: 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.
Journal of Pharmaceutical and Biomedical Analysis 12/2004; 36(3):621-4. · 2.97 Impact Factor
