Claudio Baiocchi | Università degli Studi di Torino (original) (raw)

Papers by Claudio Baiocchi

Annali di chimica

The photocatalytic oxidation of methyl-orange (C14H14N3SO3Na) dye was carried out in aqueous susp... more The photocatalytic oxidation of methyl-orange (C14H14N3SO3Na) dye was carried out in aqueous suspensions of polycrystalline TiO2 irradiated with artificial light until its complete mineralization was achieved. The performances of two widely used semiconductor powders were studied for comparison purposes. The dependence of dye photo-oxidation rate on various experimental parameters, including substrate concentration, semiconductor amount, and pH was investigated by using both catalysts. The observed dye degradation rates followed pseudo-first order kinetics with respect to the substrate concentration under the experimental conditions used. The two investigated TiO2 powders (Degussa P25 and Merck) showed different photoactivities. TOC analyses confirmed the complete mineralization achievable using both photocatalysts. Three main transient products still maintaining the chromophoric azo group were identified prior to their transformation into other degradation products which are non-ab...

International Journal of Mass Spectrometry, 2002

... Both electron and holes migrate to the surface of the semiconductor particles, where they can... more ... Both electron and holes migrate to the surface of the semiconductor particles, where they can react with water and dissolved oxygen to form various oxidizing species, including the highly reactive hydroxyl radicals, whereas superoxide and perhydroxyl radicals are formed from ...

Frontiers in Bioscience, 2010

European Journal of Lipid Science and Technology, 2011

ABSTRACT Triacylglycerols (TAG) from milk-fat from different sources (cow, goat and human milks) ... more ABSTRACT Triacylglycerols (TAG) from milk-fat from different sources (cow, goat and human milks) were characterised using non-aqueous reversed phase high-performance liquid chromatography–atmospheric-pressure chemical ionisation, coupled to MS/MS (RP HPLC-APCI MS/MS). The fatty-acid content of all samples was also established by methyl transesterification and GC-MS analysis. Optimisation of the HPLC gradient, combined with APCI tandem MS, enables TAGs complex mixtures to be analysed without prior separation. More than 160 different glycerides were identified; between 50 and 70 compounds were identified in the chromatograms of each sample. This method also enabled the principal TAG regioisomers to be recognized. The study focused on the investigation of the structure of TAGs containing very-long-chain PUFA, namely all cis- 4,7,10,13,16,19- DHA (DHA, C22:6, n-3) and all cis-5,8,11,14,17-eicosapentaenoic acid (EPA, C20:5, n-3), both in human and in n-3-enriched cow's milks. Ten TAGs containing DHA were identified in human milk and only one in milk from cows fed an n-3 enriched diet.

Chemosphere, 2002

The photodegradation of two common and very stable azo-dyes, i.e. methyl-orange (C 14 H 14 N 3 SO... more The photodegradation of two common and very stable azo-dyes, i.e. methyl-orange (C 14 H 14 N 3 SO 3 Na) and orange II (C 16 H 11 N 2 SO 4 Na), is reported. The photocatalytic oxidation was carried out in aqueous suspensions of polycrystalline TiO 2 irradiated by sunlight. Compound parabolic collectors, installed at the ''Plataforma Solar de Almer ı ıa'' (PSA, Spain) were used as the photoreactors and two identical reacting systems allowed to perform photoreactivity runs for the two dyes at the same time and under the same irradiation conditions. The disappearance of colour and substrates together with the abatement of total organic carbon content was monitored. The main sulfonate-containing intermediates were found to be in lower number in respect to those obtained under artificial irradiation. In particular there were no more evidence of the presence of hydroxylated transients. The dependence of dye photooxidation rate on: (i) substrate concentration; (ii) catalyst amount; and (iii) initial pH was investigated. The influence of the presence of strong oxidant species (H 2 O 2 , S 2 O 2À 8 ) and some ions (Cl À , SO 2À 4 ) on the process was also studied.

The kinetics and mechanisms of the oxidation of 4,4'-biphenyldiol ([1,1'-biphenyl]-4,4'-diol, I) ... more The kinetics and mechanisms of the oxidation of 4,4'-biphenyldiol ([1,1'-biphenyl]-4,4'-diol, I) to 4,4'-biphenoquinone ([bi-2,5-cycloexadiene-(1,1'-ylidene)]-4,4'-dione, II) as well as the oxidative decomposition of II by means of some metal ions (Mn m, Cd v and Ag H) have been investigated in aqueous perchlorate media at different temperatures and acidities. The oxidation of I follows the empirical rate law: -d[I]/dt = k[I][M]f([H+]), where M represents the oxidizing metal ion, and the decomposition of II: -d[II]/dt = k'[II][M]"f'([H+]), where a = 1 for Ag u and a = 0 for Ce TM and Mn m. The reaction mechanisms are proposed.

Analytica Chimica Acta, 1983

ABSTRACT

European journal of mass spectrometry (Chichester, England), 2013

The many effects of the African medicinal herb Desmodium adscendens were studied in the 1980s and... more The many effects of the African medicinal herb Desmodium adscendens were studied in the 1980s and 1990s. In spite of this, a comprehensive analytical protocol for the quality control of its constituents (soyasaponins, alkaloids and flavonoids) has not yet been formulated and reported. This study deals with the optimization of extraction conditions from the plant and qualitative identification of the constituents by HPLC-diode array UV and multistage mass spectrometry. Plant constituents were extracted from leaves by liquid-liquid and solid matrix dispersion extraction. Separation was achieved via RP-C18 liquid chromatographywith UV and MS(n) detection and mass spectrometry analysis was conducted by electrospray ionization ion trap or orbitrap mass spectrometry. High resolution mass spectrometry (HRMS) was used for structural identification of active molecules relating to soyasaponins and alkaloids. The flavonoid fragmentations were preliminarily studied by HRMS in order to accuratel...

Aqueous suspensions of titanium dioxide containing sulphonamides have been irradiated with near-U... more Aqueous suspensions of titanium dioxide containing sulphonamides have been irradiated with near-UV light. The transformation processes have been followed by monitoring both the organic intermediates and the final products. The disappearance of sulphonamides and the formation of organic intermediates have been pursued through an HPLC/MS instrument.The degradation of all the investigated sulphonamides (sulphamerazine, sulphadiazine, sulphadimethoxine and sulfathiazole) is achieved through

... The results showed no significant TOC depletion in the solutions containing cHALi only. On th... more ... The results showed no significant TOC depletion in the solutions containing cHALi only. On the contrary, in the EOcHALi solutions, a progressive TOC depletion versus irradiation time was observed, which was therefore assigned to the dye disappearance. ...

Three forms of circulating immunoreactive human growth hormone-releasing factor (ir-hGRF) have be... more Three forms of circulating immunoreactive human growth hormone-releasing factor (ir-hGRF) have been identified from a patient whose acromegaly was associated with a disseminated carcinoid tumour. This is the first known report of the molecular forms of ir-hGRF in human plasma. High performance liquid chromatography (HPLC) on a C3, wide pore reversed-phase column and gel filtration chromatography were used in conjunction with a sensitive radioimmunoassay (RIA). The greatly elevated concentration of the ir-hGRF in plasma from this patient was 25,000 ng/l (normal range less than 60 ng/l). Gel filtration (G50) chromatography of the plasma revealed a single peak which coeluted with synthetic hGRF-40. However, reversed-phase HPLC of Vycor-extracted plasma resolved the ir-hGRF into three components, which coeluted with synthetic hGRF-40 (69%), hGRF-44 (22%) and hGRF-37 (9%). At present it is not clear if the three forms are natural variants or whether either or both hGRF-40 and hGRF-37 are cleavage products of hGRF-44.

Tebuconazole is a widely used fungicide. The formation of by-products on irradiated titanium diox... more Tebuconazole is a widely used fungicide. The formation of by-products on irradiated titanium dioxide as a photocatalyst was evaluated. Several species derived from tebuconazole degradation were identified and characterized by HPLC/MSn. A pattern of reactions accounting for the observed intermediates is proposed. Different parallel pathways are operating (and through these pathways the transformation of the molecule proceeds), leading to a wide range of intermediate compounds. All these molecules are more hydrophylic than tebuconazole. The main steps involved are (1) the hydroxylation of the molecule with the formation of three species having [M + H]+ 324; the hydroxylation occurs on the C-1 carbon and on the aromatic ring in the two ortho-positions; (2) the cleavage of a C—C bond with the release of the tert-butyl moiety and the formation of a species having m/z 250; analogously to step 1, also on this species a further hydroxylation reaction occurs; (3) through the loss of the triazole moiety with the formation of a structure with m/z 257. Copyright © 2002 John Wiley & Sons, Ltd.

Food Chemistry, 2015

Natural sources of triacylglycerols containing ω-3 fatty acids are of particular interest due to ... more Natural sources of triacylglycerols containing ω-3 fatty acids are of particular interest due to their protective role against several human diseases. However, as it has been well ascertained, the position of the ω-3 fatty acid on the triacylglycerol backbone influences how digestion occurs. In particular, occurrence at the sn-2 position allows optimal intestinal absorption conditions. The analytical protocol for regioisomer characterisation of fatty acids in a triacylglycerol usually requires the use of stereospecific lipases before instrumental identification. In this paper, we propose a more direct instrumental determination of triacylglycerol composition along with sn-2 positional identification of the fatty acids constituents by Liquid Chromatography-High Resolution Mass Spectrometry. Different intensities of product signals obtained in MS(2) and MS(3) experiments were used to define an interpretative scheme able to rationalise the stereochemistry of the TAGs. Marine matrices like tuna and algae oils have been studied in detail, their triacylglycerols identified and sn-2 positional arrangement of fatty acid constituents assessed.

Journal of Mass …, 2011

... study of EI spectra of phenazone8 show the formation of [M-CH 3 ] +· , [M-CO] + and [M-CHO] +... more ... study of EI spectra of phenazone8 show the formation of [M-CH 3 ] +· , [M-CO] + and [M-CHO] +· ions. ... Claudio Medana*, Paola Calza*, Annamaria Deagostino*, Federica Dal Bello*, Elena Raso*, Claudio Baiocchi*, * Department of Analytical Chemistry, Università degli Studi di ...

Helvetica chimica …, 2002

... Thomas, A., Suárez, G., Cabrerizo, F., García Einschlag, F., Martino, R., Baiocchi, C., Prama... more ... Thomas, A., Suárez, G., Cabrerizo, F., García Einschlag, F., Martino, R., Baiocchi, C., Pramauro, E. and Capparelli, A. (2002 ... 1 Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Universidad Nacional de la Plata, Casilla de Correo 16, Sucursal 4, 1900 La ...

Phytochemistry, 2006

Salvia divinorum Epling & Játiva-M. is a perennial herb belonging to the Lamiaceae family; its ac... more Salvia divinorum Epling & Játiva-M. is a perennial herb belonging to the Lamiaceae family; its active ingredient, the neoclerodane diterpene salvinorin A, is a psychotropic molecule that produces hallucinations. A comparative evaluation of S. divinorum fresh and dried leaves, S. officinalis fresh leaves, and dried powdered leaves claimed to be S. divinorum was done. HPLC-MS data confirmed the presence of salvinorin A in both S. divinorun leaf extracts and the powdered leaves, whereas no salvinorin A was found in S. officinalis. The non-transcribed spacer (NTS) in the 5S-rRNA gene of all leaf samples and the dried powdered leaves was amplified by PCR using a pair of primers located at the 3' and 5' ends of the coding sequence of 5S-rRNA gene. The resulting PCR products (about 500bp for S. divinorum and 300bp for S. officinalis) were gel purified, subcloned into pGEM-T Easy vector and sequenced. By aligning the isolated nucleotide sequences, great diversities were found in the...