Validation of a liquid chromatography method for the simultaneous quantification of ochratoxin A and its analogues in red wines

A validated high-performance liquid chromatography (HPLC) method with fluorescence detection for the simultaneous quantification of ochratoxin A (OTA) and its analogues (ochratoxin B (OTB), ochratoxin C (OTC) and methyl ochratoxin A (MeOTA)) in red wine at trace levels is described. Before their analysis by HPLC-FLD, ochratoxins were extracted and purified with immunoaffinity columns from 50 mL of red wine at pH = 7.2. Validation of the analytical method was based on the following parameters: selectivity, linearity, robustness, limits of detection and quantification, precision (within-day and between-day variability), recovery and stability. The limits of detection (LOD) in red wine were established at 0.16, 0.32, 0.27 and 0.17 ng L-1 for OTA, OTB, MeOTA and OTC, respectively. The limit of quantification (LOQ) was established as 0.50 ng L-1 for all of the ochratoxins. The LOD and LOQ obtained are the lowest found for OTA in the reference literature up to now. Recovery values were 93.5, 81.7, 76.0 and 73.4% for OTA, OTB, MeOTA and OTC, respectively. For the first time, this validated method permits the investigation of the co-occurrence of ochratoxins A, B, C and methyl ochratoxin A in 20 red wine samples from Spain

Quantification of ochratoxin A and five analogs in Navarra red wines

Ochratoxin A (OTA), B (OTB) and their methyl (MeOTA, MeOTB) and ethyl (OTC, EtOTB) esters were evaluated in 51 red wine samples from Navarra (Spain). Detectable levels of OTA and OTB were found in 100% of the samples, and 71% showed the presence of OTC. The six ochratoxins appeared simultaneously in 18% of the samples. Results indicated that OTC is hydrolyzed to OTA in red wine. Therefore, ochratoxin intake from wine can be underestimated when only assessed by OTA analysis. Analyzed Navarra wines are scarcely contaminated with ochratoxins and their contribution to human intake is low, with the worst case being 4.7% and 6.6% of the provisional tolerable weekly intake (PTWI) for OTA and for the sum of ochratoxins, respectively. No significant differences were generally found between vintages. With the exception of OTA, no significant differences were observed between organic and traditional farming. Levels of ochratoxins were positively correlated with temperature and inversely correlated with humidity and rainfall

Levels of ochratoxins in Mediterranean red wines

The co-occurrence of ochratoxin A (OTA) and its five analogs (OTB, OTC, MeOTA, MeOTB and EtOTB) in 96 red wine samples from Mediterranean countries has been demonstrated, for the first time, in this study. OTA was detected in 99 % of the samples (<LOD-455 ng·L-1). This mycotoxin appeared simultaneously with OTB (2.05 - 119 ng·L-1) in all the samples and in 89.6% of them OTC (<LOD - 31.5 ng·L-1) also accompanied both. OTB appears at comparable levels and incidence just like OTA does, and OTC median concentration is approximately 10 % of that of OTA. A high statistical association was found between the concentrations of OTA-OTB and OTA-OTC. MeOTA, MeOTB and EtOTB were detected in 62.5, 83.3 and 83.3 % of the samples, respectively. In 44.8 % of the wines, the 6 ochratoxins appeared simultaneously. There was no evidence for ochratoxin A levels being greater in wines from Southern Europe than those described from North Europe. Samples from North Africa presented statistically the highest values for OTA, OTB, OTC and EtOTB

A π-Extended Donor-Acceptor-Donor Triphenylene Twin linked via a Pyrazine-bridge

Beta-amino triphenylenes can be accessed via palladium catalyzed amination of the corresponding triflate using benzophe-none imine. Transformation of amine 6 to benzoyl amide 18 is also straightforward and its wide mesophase range demon-strates that the new linkage supports columnar liquid crystal formation. Amine 6 also undergoes clean aerobic oxidation to give a new twinned structure linked through an electron-poor pyrazine ring. The new discotic liquid crystal motif contains donor and acceptor fragments, and is more oval in shape rather than disk-like. It forms a wide range columnar mesophase. Absorption spectra are strong and broad; emission is also broad and occurs with a Stokes shift of ca. 0.7 eV, indicative of charge-transfer characte

Political & Quasi-Adjudicative Dispute Settlement Models in European Union Free Trade Agreements - Is the Quasi-Adjudicative Model a Trend or is it Just Another Model?

In this paper, interpretation and application dispute settlement provisions of European Union (EU) Free Trade Agreements (FTAs) signed between 1963 and 2006 are analysed. This will be through the two models of Dispute Settlement in International Law: the political and adjudicative. Political elements of dispute settlement mechanisms in Public International Law and General Agreement of Tariffs and Trade (GATT) served to establish those of the EU FTAs. Adjudicative and quasi-adjudicative elements of dispute settlement mechanisms of Public International Law and World Trade Organization (WTO) Law were used as parameters to set up those of the EU FTAs. These parameters also helped to define a new and unique hybrid model. The features of this model were found in Agreements with trade issues other than FTAs. It is possible, however, for future FTAs to incorporate them. The hybrid model is based on an adjudicative framework and includes both political and adjudicative elements. In conclusion, it was found that even though WTO Members incorporated adjudicative elements in the Dispute Settlement Understanding (DSU), the EU did not incorporate them bilaterally for a further five years. Furthermore, since the creation of the DSU in 1995, the EU has established more FTAs based on a political model than on a quasi-adjudicative. Consequently, the quasi-adjudicative dispute settlement model has not represented a clear trend in EU FTAs

Incidencia y niveles de Ocratoxina A y cinco análogos en vino tinto

The natural presence of OTA in wine has been reported worldwide. However, this is the first investigation that has demonstrated the co-occurrence of several ochratoxins in 51 red wines from Navarra (Spain) and 96 samples from 8 Mediterranean countries. This fact is partly due to the low limits of detection and quantification obtained. An HPLC-FLD analytical method was developed and validated for the simultaneous quantification of ochratoxin A (OTA), ochratoxin B (OTB) and their methyl and ethyl esters (methylochratoxin A (MeOTA), ochratoxin C (OTC), methylochratoxin B (MeOTB) and ethylochratoxin B (EtOTB)) in red wine. No samples exceeded the 2 µg/L maximum permitted by the EU for OTA in wine. Simultaneous occurrence of OTA and OTB were found in 100% of the samples. In addition, 90% of the Mediterranean wines presented OTC and the six ochratoxins were detected in 45%. OTA-OTB and OTA-OTC concentrations showed a very large positive association between each other. In general, levels were not influenced by the country of origin except in the case of Tunisia and Algeria, whose concentrations were statistically higher. Some factors that could affect the ochratoxin levels were investigated. In general, no significant differences were found between vintages. With the exception of OTA, no significant differences were observed between organic and traditional farming. Concentrations were positively correlated with temperature and inversely correlated with humidity and rainfall during the summer prior to grape harvesting. OTC transformation into OTA in red wine was also examined. The results obtained suggested that OTC hydrolyzed to OTA in wine

Incidencia y niveles de Ocratoxina A y cinco análogos en vino tinto

The natural presence of OTA in wine has been reported worldwide. However, this is the first investigation that has demonstrated the co-occurrence of several ochratoxins in 51 red wines from Navarra (Spain) and 96 samples from 8 Mediterranean countries. This fact is partly due to the low limits of detection and quantification obtained. An HPLC-FLD analytical method was developed and validated for the simultaneous quantification of ochratoxin A (OTA), ochratoxin B (OTB) and their methyl and ethyl esters (methylochratoxin A (MeOTA), ochratoxin C (OTC), methylochratoxin B (MeOTB) and ethylochratoxin B (EtOTB)) in red wine. No samples exceeded the 2 µg/L maximum permitted by the EU for OTA in wine. Simultaneous occurrence of OTA and OTB were found in 100% of the samples. In addition, 90% of the Mediterranean wines presented OTC and the six ochratoxins were detected in 45%. OTA-OTB and OTA-OTC concentrations showed a very large positive association between each other. In general, levels were not influenced by the country of origin except in the case of Tunisia and Algeria, whose concentrations were statistically higher. Some factors that could affect the ochratoxin levels were investigated. In general, no significant differences were found between vintages. With the exception of OTA, no significant differences were observed between organic and traditional farming. Concentrations were positively correlated with temperature and inversely correlated with humidity and rainfall during the summer prior to grape harvesting. OTC transformation into OTA in red wine was also examined. The results obtained suggested that OTC hydrolyzed to OTA in wine