Determination of Domoic Acid in Plankton Net Samples from Golden Horn Estuary, Turkey, Using HPLC with Fluorescence Detection.

This study focused on the fluctuations of domoic acid (DA) levels in plankton net samples collected from the Golden Horn Estuary (GHE), Turkey, between August 2011 and July 2012. DA concentrations were determined by high-performance liquid chromatography (HPLC), using a fluorenylmethoxycarbonyl (FMOC) derivatization technique. Monthly and biweekly data were evaluated with environmental variables, and their influence on DA production is discussed. DA levels in plankton net samples varied between 0.36 and 94.34 µg L- 1. DA levels showed remarkable seasonal variation and they were generally higher in May, 2012, but no DA was detected between February and April, 2012. DA production was mostly controlled by temperature, with nitrate and silicate limitations being secondary factors that influenced DA concentrations.

The First Observation of Domoic Acid in Plankton Net Samples from the Sea of Marmara, Turkey.

This study reports the first evidence of domoic acid (DA), an algal neurotoxin produced by the genus Pseudo-nitzschia, from plankton net samples collected in the Sea of Marmara in December, 2010 and February, 2011. DA concentrations of plankton net samples were analyzed by high-performance liquid chromatography (HPLC), using the fluorenylmethoxycarbonyl fluorescence derivatization technique (detection limit 0.2 ng DA). The biotoxin concentrations in samples from coastal waters varied between 0.96 and 5.25 µg DA/mL. We also investigated possible correlations between physicochemical parameters and DA concentration. The DA levels appear to be correlated negatively with silica and nitrite concentrations for both sampling periods. These data may be used to evaluate the probability of finding similar conditions in coastal waters of the Sea of Marmara in order to determine the potential risks to local aquaculture and fisheries.

Natural co-occurrence of ochratoxin A, ochratoxin B and aflatoxins in Sicilian red wines.

The natural occurrence of ochratoxin A, ochratoxin B, aflatoxin B1, aflatoxin B2, aflatoxin G1 and aflatoxin G2 (OTA, OTB, AFB1, AFB2, AFG1, AFG2) in red wines was investigated by HPLC/FLD after immunoaffinity column clean-up in 57 market samples produced in Sicily (Italy). The results showed a very low incidence of these mycotoxins in analysed samples, confirming the high degree of quality and safety of Sicilian red wines. The results indicated 71.9% and 64.9% positive samples for OTA and OTB respectively, with an average level of 0.13 µg l(-1), well below the European maximum permitted levels (MLs). The aflatoxin most frequently detected in the samples was AFG1, present in 57.9% of samples, while the other aflatoxins were rarely present. Recovery experiments were carried out on eight mycotoxin-free red wines spiked with OTA, OTB, AFB1, AFB2, AFG1 and AFG2 at two different levels. The limits of detection (LODs) in wines were 0.02 µg l(-1) for OTA, 0.04 µg l(-1) for OTB, 0.03 µg l(-1) for AFG1, AFG2 and AFB2, and 0.05 µg l(-1) for AFB1. A good correlation was found, with good performances in term of precision for the method.

Comparison of extraction methods for analysis of citrinin in red fermented rice.

There is no standard method for the extraction and analysis of citrinin in red fermented rice (RFR). In the study, five extraction methods were compared for their efficiency to analyse citrinin in RFR by HPLC-FLD (reversed phase high performance liquid chromatography with fluorescence detection), including, (1) ultrasonic extraction with EW solution (ethanol:water, 7:3, v/v); (2) ultrasonic extraction with TEF solvent mixtures (toluene:ethyl acetate:formic acid, 7:3:1, v/v); (3) shaking extraction with EW; (4) shaking extraction with EF solvent mixtures (ethyl acetate:formic acid, 1:1, v/v); (5) shaking combined with ultrasonic extraction in EW. Comparison of chromatograms of citrinin by HPLC-FLD with different extraction methods revealed that EW was the best extraction solvent. It was also found that shaking combined with ultrasonic extraction in EW was the most efficient extraction method to extract citrinin from RFR for qualitative and quantitative analysis.