摘要:

This paper describes the first part of a project undertaken to develop mussel reference materials for Paralytic Shellfish Poisoning (PSP) toxins. Two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin (STX) and decarbamoyl-saxitoxin (dc-STX) in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the second part of the project: the certification exercise. In the first study, 18 laboratories were asked to measure STX and dc-STX in rehydrated lyophilized mussel material and to identify as many other PSP toxins as possible with a method of their choice. In the second interlaboratory study, 15 laboratories were additionally asked to determine quantitatively STX and dc-STX in rehydrated lyophilized mussel and in a saxitoxin-enriched mussel material. The first study revealed that three out of four postcolumn derivatization methods and one pre-column derivatization method sufficed in principle to determine STX and dc-STX. Most participants (13 of 18) obtained acceptable calibration curves and recoveries. Saxitoxin was hardly detected in the rehydrated lyophilized mussels and results obtained for dc-STX yielded a CV of 58% at a mass fraction of 1.86 mg/kg. Most participants (14 out of 18) identified gonyautoxin-5 (GTX-5) in a hydrolysed extract provided. The first study led to provisional criteria for linearity, recovery and separation. The second study revealed that 6 out of 15 laboratories were able to meet these criteria. Results obtained for dc-STX yielded a CV of 19% at a mass fraction of 3.49mg/kg. Results obtained for STX in the saxitoxin-enriched material yielded a CV of 19% at a mass fraction of 0.34mg/kg. Saxitoxin could not be detected in the PSP-positive material. Hydrolysis was useful to confirm the identity of GTX5 and provided indicative information about C1 and C2 toxins in the PSP-positive material. The methods used in the second interlaboratory study showed sufficiently consistent analysis results to undertake a certification exercise to assign certified values for STX and dc-STX in lyophilized mussel.

ISSN:0265-203X    

DOI:10.1080/02652030050034000

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Over the last century, the atmospheric fallout of anthropogenic lead has evolved with time, as a function of the chronological variability of transient lead inputs from both industrial and gasoline origins. This variability has been mostly documented over North America and northern Europe. In this study we used ICP-MS for the determination of lead isotope ratios and showed that a series of French wines followed the evolution of the environmental lead record over the last century. We observe the same three-step chronological evolution of the lead isotopic composition, which reflects a western European signal. In the post 1950 vintages, the lead isotope composition reflects a dominant atmospheric fallout. Since ˜1950, Pb concentrations have been much lower than before, decreasing consistently from ˜0.25mg l-1around the early 1950s, down to less than ˜0.1mg l-1nowadays. Reflecting the airborne pollution, the lead isotopic signature is also specific of the continental origin of the wines and lead isotope ratios determination in wines appears to be a promising tool for certifying wine authenticity.

ISSN:0265-203X    

DOI:10.1080/02652030050034019

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The aims of this study were to determine the levels of some toxic and trace metals in cattle meat in Spain and to compare them with concentrations in cattle elsewhere and to maximum acceptable levels. Arsenic, cadmium, lead, copper and zinc concentrations in the liver, kidney and muscle (meat) from 438 calves (6–10 months old) and 56 cows (2–16 years old) slaughtered in Galicia (NW Spain) in 1996 were quantified. The arithmetic mean fresh weight concentrations in calf liver, kidney and muscle respectively were 0.043, 0.055, 0.004mg/kg for arsenic, 0.032, 0.070, 0.001 mg/kg for cadmium, 0.053, 0.052, 0.009 mg/kg for lead, 64.6, 4.91, 0.677mg/kg for copper and 47.7, 14.4, 47.8mg/kg for zinc. In cows, these concentrations were 0.046, 0.068, 0.005mg/kg (arsenic), 0.097, 0.458, 0.001mg/kg (cadmium), 0.057, 0.066, 0.017mg/kg (lead), 60.3, 3.67, 1.26 mg/kg (copper) and 59.8, 20.0, 52.7mg/kg (zinc). Except for copper levels in the liver which were high, metal concentrations in cattle were generally low in Galicia and broadly similar to those in the rest of Europe, Australia and Canada. Arsenic, cadmium and lead concentrations in Galician cattle rarely exceeded acceptable maximum concentrations that have been adopted by many countries. Copper and zinc concentrations in Galician cattle did exceed acceptable maximum concentrations but the frequency with which this occurred depended upon which acceptable maximum concentration was used; regulatory values differ markedly between countries.

ISSN:0265-203X    

DOI:10.1080/02652030050034028

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The present study was carried out to evaluate the excretion of aflatoxin B1residues in eggs of young laying hens fed aflatoxin B1-contaminated rations for 8 weeks. To this end, 96 twenty-week-old hens were randomly distributed into four experimental groups (24 birds per group) and given rations containing either 0 (controls), 100 μg, 300 μg or 500 μg aflatoxin B1/kg feed. Egg aflatoxin B1residues were determined by thin layer chromatography; two samples per treatment per week were used for analysis. Egg production and average egg weights were not affected (p < 0.05) in the groups receiving aflatoxin B1-contaminated rations. Residues of aflatoxin B were detected only in the eggs 1 of hens given 500 μg/kg feed, at levels that ranged from 0.05 to 0.16 μg/kg (average: 0.10 μg/kg). The results indicate that the feed to eggs aflatoxin B transmission 1 ratio was approximately 5000:1, emphasizing the importance of controlling aflatoxin levels in rations for laying hens.

ISSN:0265-203X    

DOI:10.1080/02652030050034037

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

A method for determining fumonisin B1(FB1) in corn was developed and the clean-up optimized in order to give an extract suitable for one-dimensional thin layer chromatographic (TLC) analysis. FB1was extracted with a solution of methanol:water (80:20,v/v), purified through an immunoaffinity column and separated on a C18reversed phase TLC plate. The FB1was visualized with 0.1mol/l sodium tetraborate, 0.40mg/ml fluorescamine in acetonitrile and 0.01mol/l boric acid:acetonitrile (2:3,v/v) for fluorescence detection, and quantified by densitometric analysis. Water, acetonitrile:water (1:1v/v) and acetonitrile:water (4:1v/v) were evaluated as TLC solvents for running both standards and samples together with derivatization procedures aimed at improving separation, resolution, sensitivity and linearity. The mean recovery for FB1for spiked samples was found to be 85% and the linear equation of standard calibration curve by densitometric analysis gave an r2value higher than 0.99. The maximum coefficient of variation for replicate analysis of spiked samples was 19%. The absolute amount of FB1standard detectable on a TLC plate was 2 ng, giving a detection limit for the method of 0.1mg/kg. The method has been shown to be robust in the application of FB1monitoring in corn (214 samples) collected in different regions of the country. FB1was detected in 99% of these samples in the range of 0.2 to 6 mg/kg.

ISSN:0265-203X    

DOI:10.1080/02652030050034046

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Ethyl carbamate has been associated with cancer for several decades. It is mainly found in fermented foods and beverages. In view of the importance of fermented foods in the Korean diet and the significant level of ethyl carbamate expected, we determined ethyl carbamate concentrations in some of the staple food items and estimated the daily intake for the Korean population. Ethyl carbamate in commercial samples of kimchi, soy sauce, vinegar, soybean paste, and alcoholic beverages were determined by gas chromatography-mass spectrometry/selective ion monitoring (GC-MS/SIM). Homemade soy sauce and kimchi were also analysed. The maximum ethyl carbamate concentrations observed were 73 μg/kg in soy sauce, 7.9 μg/kg in soybean paste, 2.5 μg/l in vinegar, 16.2 μg/kg in kimchi and 15.4 μ/l in Korean traditional alcoholic beverages. Combining these values with the average daily food intake data, we estimated that the maximum daily exposure of Korean population to ethyl carbamate is 2.8 μg/day, which is not a negligible amount considering the ‘virtually safe dose’ derived by animal experiment ranges between 1.2 and 4.8 μg/day. It would be desirable to closely monitor ethyl carbamate levels in Korean foods and to find ways to reduce the daily intake.

ISSN:0265-203X    

DOI:10.1080/02652030050034055

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

ISSN:0265-203X    

DOI:10.1080/02652030050034064

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor