Antonio Segura Carretero

Determination of phenolic compounds in modern and old varieties of durum wheat using liquid chromatography coupled with time-of-flight mass spectrometry.

An evaluation of the grain functional components of Italian durum wheat cultivars was conducted. The raw material was obtained from the field trial performed in 2006-2007 at the Experimental Farm of the University of Bologna, (Bologna, Italy). The aim of this study was to define the phytochemical profile of ten varieties, comprised of old and modern durum wheat genotypes, including quantitative and qualitative phenolic and flavonoid content (free and bound forms). The results showed that mean values of total phenolic compound and total flavonoid content in old wheat varieties (878.2+/-19.0 micromol gallic acid equivalent/100g of grain and 122.6+/-25.4 micromol catechin equivalent/100g of grain, respectively) did not differ significantly from those detected in modern genotypes (865.9+/-128.9 micromol gallic acid equivalent/100g and 123.5+/-20.6 micromol catechin equivalent/100g, respectively). However, the HPLC-ESI-TOF-MS analysis highlighted remarkable differences between modern and old cultivars. The interpretation of the mass spectra allowed the identification of 70 phenolic compounds, including coumarins, phenolic acids, anthocyanins, flavones, isoflavones, proanthocyanidins, stilbenes and lignans. The free extracts of ancient wheat varieties showed the presence of a mean number of phenolic compounds and isomer forms (8.7+/-2.5 and 7.7+/-4.7 respectively) significantly higher than in modern genotypes (4.4+/-2.9 and 2.0+/-2.4, respectively). A similar trend was observed also for the bound phenolic fraction. Moreover, the phytochemical profiles showed the presence of unique phenolic compounds in both free and bound fractions of some of the investigated wheat genotypes. Results highlighted that investigated old wheat cultivars may offer unique nutraceutical values for their peculiar contents in bioactive phytochemicals, suggesting their uses into a wide range of regular and specialty products naturally enriched with health-promoting compounds.

Electrophoretic identification and quantitation of compounds in the polyphenolic fraction of extra-virgin olive oil.

A capillary zone electrophoresis method has been carried out to determine and quantitate some compounds of the polyphenolic fraction of virgin olive oil which have never previously been determined before using capillary electrophoresis, such as elenolic acid, ligstroside aglycon, oleuropein aglycon, and (+)‐pinoresinol. The compounds were identified using standards obtained by semipreparative high‐performance liquid chromatography (HPLC). A detailed method optimization was performed to separate the phenolic compounds present in olive oil using a methanol–water extract of Picual extra‐virgin olive oil, and different extraction systems were compared (C18‐solid phase extraction (SPE), Diol‐SPE, Sax‐SPE and liquid‐liquid extraction). The optimized parameters were 30 mM sodium tetraborate buffer (pH 9.3) at 25 kV with 8 s hydrodynamic injection, and the quantitation was carried out by the use of two reference compounds at two different wavelengths.

An innovative way of obtaining room-temperature phosphorescence signals in solution

This manuscript presents an innovative way of obtaining room temperature phosphorescence (RTP) in solution. For the first time, the RTP of naphthalene derivatives have been observed in solution without using any kind of organized media. The RTP signals are a consequence of intermolecular protection when analytes are exclusively in the presence of a heavy atom salt and sodium sulfite is employed as an oxygen scavenger to minimize RTP quenching. A rigorous study of numerous experimental and instrumental variables has been carried out.

A Review of Heavy-Atom-Induced Room-Temperature Phosphorescence: a Straightforward Phosphorimetric Method

Abstract This review discusses the development of heavy-atom-induced, room-temperature phosphorescence (HAI-RTP), a new technique based on the use of RTP emitted directly from the analyte in a fluid solution with no protective medium except the presence of high concentrations of a heavy-atom perturber. These experimental conditions permit sufficient interaction between the perturber and the analytes to produce an effective population of their triplet states and thus emit intense phosphorescence.

Simple and rapid determination of the drug naproxen in pharmaceutical preparations by heavy atom-induced room temperature phosphorescence

A simple, selective and sensitive heavy atom-induced room temperature phosphorimetric method (HAI-RTP) is described for the determination of naproxen (NAP) in pharmaceutical preparations. The phosphorescence signals are a consequence of intermolecular protection when analytes are, exclusively, in presence of a heavy atom salt and sodium sulfite as an oxygen scavenger to minimize RTP quenching. These variables selection constitute the basis of a HAI-RTP method for the determination of naproxen (detection limit 17.6 ng ml(-1); 1.71% relative standard deviation at 250 ng ml(-1)). The method has been applied satisfactorily to the analysis of pharmaceutical preparations.

Volatile-organic-compound optic fiber sensor using a gold-silver vapochromic complex

We describe a new gold-silver complex based on 2,2-bipyridine, whose formula is Au2Ag2C6F54C5H4N-C5H4N2n, used to detect volatile organic compounds VOCs such as ethanol, methanol, and acetic acid. This organometallic material is presented in the form of bright yellow powder, and suffers a change in its optical properties when it is exposed to VOCs. A new fiber optic sensor is pre- sented based on the properties of a new vapochromic material. The sensor works in a reflection configuration and consists of an optic fiber pigtail core diameter is 200 m and cladding is 230 m on the cleaved end of which the vapochromic material, previously mixed with a commer- cially available solvent, Liquicoat ® , is deposited by using the dip-coating technique. Using an optical source and a photodetector, it is possible to detect and quantify the change in reflected intensity-modulated signal when the sensor is exposed to VOC inside a sealed chamber. This be- havior can be related to the VOC concentration. The study of the sen- sors response is made at a specific wavelength for different VOC con- centrations. Limits of detection of 2.16, 1.73, and 3.73 mg/L of vapors of ethanol, methanol, and acetic acid vapors, respectively, are attained.

A bioguided identification of the active compounds that contribute to the antiproliferative/cytotoxic effects of rosemary extract on colon cancer cells

Rosemary extracts have exhibited potential cytostatic or cytotoxic effects in several cancer cell models but their bioactive compounds are yet to be discovered. In this work, the anticancer activity of a rosemary-leaf extract and its fractions were assayed to identify the phenolic compounds responsible for their antiproliferative/cytotoxic effects on a panel of human colon cancer cell lines. Bioguided fractionation of the rosemary-leaf extract was achieved by semi-preparative chromatography. The rosemary extract and the compounds in the fractions were characterized and quantified by HPLC-ESI-QTOF-MS. Cellular viability in the presence of these fractions and the whole extract was determined after 24 or 48 h incubations by using an MTT assay. Fractions containing diterpenes or triterpenes were the most active but not as much as the whole extract. In conclusion, carnosic acid, carnosol, 12-methoxycarnosic acid, taxodione, hinokione and betulinic acid were the putative candidates that contributed to the observed antiproliferative activity of rosemary in human colon cancer cells. Whether the effects of the extract and fractions are only cytostatic or cytotoxic needs to be elucidated. Nevertheless, the comparative antiproliferative study on the fractions and whole extract revealed potential synergistic effects between several components in the extract that may deserve further attention.

The development of solid-surface fluorescence characterization of polycyclic aromatic hydrocarbons for potential screening tests in environmental samples

This paper presents the characterization of polycyclic aromatic hydrocarbons (PAHs) in solid-surface fluorescence as the first step for obtaining new optical sensors for PAHs screening. The fluorescence properties of the EPA-PAHs (naphthalene, acenaphthene, acenaphthylene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, chrysene, benzo[a]anthracene, benzo[k]fluoranthene, benzo[b]fluoranthene, benzo[a]pyrene, indeno [1,2,3-cd]pyrene, benzo[g,h,i]perylene and dibenzo[a,h]anthracene) on five types of solid-surfaces were evaluated. The experimental variables (pH and percentage of organic solvent in samples) were studied, obtaining different possibilities for making individual sensors for some of these PAHs and the best conditions for developing sensors for PAH screening were also studied.

Application of variable-angle synchronous phosphorimetry in a microemulsion medium for the simultaneous determination of three polyaromatic hydrocarbons

The applicability of variable-angle synchronous scanning (VASS) phosphorimetry at room temperature has been demonstrated, for the first time, for the simultaneous determination of the polycyclic aromatic hydrocarbons phenanthrene, fluoranthene and benz[a]anthracene. This technique permits linear or non-linear paths to be scanned at preselected angles through the excitation-emission phosphorescence matrix in order to obtain the highest signal values and interference-free bands. The phosphorescence emissions of the three compounds have been obtained using microemulsion aqueous solutions in an apolar solvent. In order to obtain the optimum spectrophosphorimetric responses, a statistical model of central composite design type was applied. The increased selectivity afforded by the VASS technique has permitted the simultaneous determination of the three phosphorescent compounds with closely overlapping profiles added to coffee samples giving mean recoveries of 94% with a relative standard deviation of 1.5%.

Room-temperature phosphorimetric method for the determination of the drug naphazoline in pharmaceutical preparations

A selective and sensitive micelle-stabilized room-temperature phosphorimetric (MS-RTP) method for the determination of naphazoline in pharmaceutical preparations is described. The method is based on obtaining a phosphorescence signal from naphazoline using a micellar agent (sodium dodecyl sulfate), a heavy atom salt (TlNO3) and a deoxygenation agent (Na2SO3). Optimization of the various conditions permitted the establishment of an MS-RTP method for naphazoline determination with a detection limit of 64.2 ng ml–1 and a relative standard deviation of 3.74% at the 500 ng ml–1 level. The method was applied to the analysis of pharmaceutical preparations.