NovaSil clay does not affect the concentrations of vitamins A and E and nutrient minerals in serum samples from Ghanaians at high risk for aflatoxicosis

To assess the potential interference of NovaSil (NS) clay with micronutrients in humans, vitamins A and E and minerals (15 nutrient and 15 non-nutrient minerals) were measured in serum samples from a 3-month intervention trial with NS. Participants (n = 177) were randomly divided into three groups that received 3.0 g NS day(-1) (high dose, HD), 1.5 g NS day(-1) (low dose, LD), or placebo (PL). Levels of vitamins A and E in serum were comparable among the three study groups at baseline, 1 month and 3 months of NS intervention. Gender-stratified non-parametric mixed-effect model analysis showed no significant effects of dose and dose-time interaction for levels of vitamins A and E. A significant time effect was detected; however, it was limited to an increase in vitamin E in the male participants over the course of the study. No significant differences were found in levels of the nutrient and non-nutrient minerals between the HD and PL groups at baseline and 3 months of NS intervention, except for strontium levels. Strontium was significantly increased (p < 0.001) in the HD group (male = 113.65 +/- 28.00 microg l(-1); female = 116.40 +/- 24.26 microg l(-1)) compared with the PL group (male = 83.55 +/- 39.90 microg l(-1); female = 90.47 +/- 25.68 microg l(-1)) following the 3-month intervention with NS. These results, combined with safety and efficacy data, confirm that NS clay is highly effective in reducing aflatoxin exposure and acts as a selective enterosorbent that does not affect the serum concentrations of important vitamins and nutrient minerals in humans.     

Aflatoxin–albumin adducts and correlation with decreased serum levels of vitamins A and E in an adult Ghanaian population

A study of aflatoxin (AF) exposure and the levels of vitamins A and E was carried out with a group of 507 Ghanaian participants. AFB₁–albumin adducts (AFB-AA) were measured by radioimmunoassay and vitamins A and E were measured by high-performance liquid chromatography (HPLC). The average level of serum AFB-AA was 0.94 ± 0.64 (range = 0.1–4.44) pmol mg^?1 albumin. Mean levels of vitamins A and E were 1.32 ± 0.48 (range = 0.41–4.85) µmol l^?1 and 15.68 ± 4.12 (range = 6.35–30.40) µmol l^?1, respectively. A significantly negative correlation was found between serum AFB-AA and vitamin A levels (r = ?0.110, p = 0.013). An even stronger, significant negative, correlation was found between serum AFB-AA and vitamin E levels (r = ?0.149, p < 0.001). Serum AFB-AA levels were statistically higher (median = 0.985 pmol mg^?1 albumin) in subjects who had low levels of both vitamins A and E as compared with the levels (median = 0.741 pmol mg^?1 albumin) subjects who had high vitamins A and E levels (p _trend = 0.001). To verify these findings, blood samples were again collected from 165 of the 507 people 3 months after the initial collection. Significantly negative correlations were confirmed between levels of serum AFB-AA and both vitamins A (r = ?0.232, p = 0.003) and E (r = ?0.178, p = 0.023). Again, high serum AFB-AA concentrations (median = 1.578 pmol mg^?1 albumin) were found in subjects with low levels of vitamins A and E compared with the concentrations (median = 1.381 pmol mg^?1 albumin) in subjects with high levels of vitamins A and E (p _trend = 0.002). These data show that AF exposure was associated with decreased levels of serum vitamins A and E in high-risk human populations, which may significantly influence the incidence of AF-related adverse health effects.     

Aflatoxins and cyclopiazonic acid in feed and milk from dairy farms in São Paulo,Brazil

The occurrence of aflatoxins (AF) B₁, B₂, G₁, G₂ and cyclopiazonic acid (CPA) in feeds, and AFM₁ and CPA in milk was determined in dairy farms located in the northeastern region of São Paulo state, Brazil, between October 2005 and February 2006. AF and CPA determinations were performed by HPLC. AFB₁ was found in 42% of feed at levels of 1.0–26.4 µg kg^?1 (mean: 7.1 ± 7.2 µg kg^?1). The concentrations of AFM₁ in raw milk varied between 0.010 and 0.645 µg l^?1 (mean: 0.104 ± 0.138 µg l^?1). Only one sample was above the tolerance limit adopted in Brazil (0.50 µg l^?1) for AFM₁ in milk. Regarding CPA in feed, six (12%) samples showed concentrations of 12.5–153.3 µg kg^?1 (mean: 57.6 ± 48.7 µg kg^?1). CPA was detected in only three milk samples (6%) at levels of 6.4, 8.8 and 9.1 µg l^?1. Concentrations of aflatoxins and CPA in feed and milk were relatively low, although the high frequency of both mycotoxins indicates the necessity to continuously monitor dairy farms to prevent contamination of feed ingredients.     

Monoclonal-based enzyme-linked immunosorbent assay for the detection of zearalenone in cereals

A monoclonal antibody against zearalenone (ZEA) was produced and used successfully to develop a direct competitive enzyme-linked immunosorbent assay (DC-ELISA) for the analysis of ZEA in cereals. This DC-ELISA had a limit of detection of 0.15?±?0.02 µg l^?1 and an IC₅₀ value of 1.13?±?0.16 µg l^?1. Matrix interference was minimized by dilution of the sample extract before ELISA assays. Aqueous methanol (80%) gave good extraction efficiencies, and the recovery from spiked rice, barley, and corn samples averaged between 87 and 112%. Although ZEA was detected in seven (9%) of 80 rice samples and in eight (16%) of 50 barley samples, the concentration of ZEA in samples was around or below the limit of detection of DC-ELISA. Among 38 corn samples, ZEA was detected in nine (24%) samples in the range 41.0–909.8 µg kg^?1. Re-analysis of the ELISA-positive corn samples by high-performance liquid chromatography (HPLC) confirmed that seven (18%) corn samples were positive. The ZEA results for corn showed very good agreement between DC-ELISA and a commercial AgraQant® zearalenone kit (r ²?=?0.98). Thus, the monoclonal antibody-based DC-ELISA could be applied to the preliminary screening of ZEA contamination when analysis of a large sample number is needed.     

Enhanced screening efficiency for endocrine-disrupting chemicals in milk and powdered milk using UPLC/QTOF-MS by the introduction of dansyl chloride derivatisation

This study developed and validated a sensitive analytical method for simultaneous screening of four classes of endocrine-disrupting chemicals (i.e. progestogens, androgens, oestrogens and phenols) in milk and powdered milk using ultra-performance liquid chromatography (UPLC) coupled with electrospray ionisation quadrupole time-of-flight mass spectrometry (QTOF-MS). Dansylation of oestrogens and phenols enhanced the ionisation efficiency and shifted the ionisation mode from negative to positive, which allowed for the simultaneous analysis of four EDCs in one chromatographic run. An efficient sample pre-treatment minimised the matrix effects. The mass errors for the precursor and product ions for 26 target compounds varied between ?2.8 and 2.3?mDa; and the limits of detection (signal-to-noise ratio?=?3) for milk and powdered milk were less than 0.04?µg?l^?1 and 0.10?µg?kg^?1, respectively. The proposed method was successfully used to analyse multiple types of real samples, including normal temperature whole milk, infant formula and whole powdered milk. In 11 samples, two target compounds, progesterone and androstenedione, were detected. The progesterone concentrations ranged from 8.1 to 12.7?µg?l^?1 in milk, and from 1.2 to 32.0?µg?kg^?1 in infant formulas and whole powdered milks. The androstenedione concentrations varied from 0.39 to 0.79?µg?l^?1 in milks, and from 0.29 to 1.2?µg?kg^?1 in infant formulas and whole powdered milks. Two post-target compounds, one isomer of oestriol and 5α-dihydroprogesterone, were tentatively identified by post-target analysis in two of 11 real samples.     

NovaSil clay intervention in Ghanaians at high risk for aflatoxicosis: II. Reduction in biomarkers of aflatoxin exposure in blood and urine

The efficacy of NovaSil clay (NS) to reduce aflatoxin (AF) biomarkers of exposure was evaluated in 656 blood samples and 624 urine samples collected from study participants during a 3-month phase IIa clinical intervention trial in Ghana. NS was delivered before meals via capsules. Serum AFB₁–albumin adduct was measured by radioimmunoassay and urinary AFM₁ metabolites were quantified by immunoaffinity-high-performance liquid chromatography (HPLC)-fluorescence methods. Levels of AFB₁–albumin adduct in serum samples collected at baseline and at 1 month were similar (p?=?0.2354 and p?=?0.3645, respectively) among the placebo (PL), low dose (LD, 1.5 g NS day^?1), and high dose (HD, 3.0 g NS day^?1) groups. However, the levels of AFB₁–albumin adduct at 3 months were significantly decreased in both the LD group (p?<?0.0001) and the HD group (p?<?0.0001) compared with levels in the PL group. Levels of AFM₁ in urine samples collected at baseline and at 1 month were not statistically different among the three study groups. However, a significant decrease (up to 58%) in the median level of AFM₁ in samples collected at 3 months was found in the HD group when compared with the median level in the PL group (p?<?0.0391). In addition, significant effects were found for dose, time, and dose–time interaction with serum AFB₁–albumin adduct and dose–time interaction with urinary AFM₁ metabolites. The results suggest that capsules containing NS clay can be used to reduce effectively the bioavailability of dietary AF based on a reduction of AF-specific biomarkers.     

Development of a novel solid-phase extraction,LC-MS/MS method for the analysis of ethyl carbamate in alcoholic beverages: application to South African wine and spirits

Ethyl carbamate (EC) is a known genotoxic carcinogen that is frequently present in alcoholic beverages and is therefore a public health concern. As a consequence, maximum concentration levels for EC in these commodities are legislated in several countries. Quantitative analytical methods are therefore essential to monitor EC levels in beverages. Most published analytical methods for the determination of EC in alcoholic beverages utilise elaborate sample pre-treatment procedures to obtain injectable samples, or yield low sensitivity, for example where direct injection is used. In addition, these procedures often require large volumes of toxic solvents and are not generally applicable to diverse alcoholic beverages. This paper describes a novel procedure for the determination of EC in wines, fortified wines and spirits. The procedure is based on reversed-phase solid-phase extraction (SPE) sample clean-up combined with normal-phase liquid chromatography-atmospheric pressure chemical ionisation tandem mass spectrometric (NP-LC-APCI-MS/MS) analysis. This method provides a rapid, robust and simple analytical procedure suitable for the analysis of a diverse range of alcoholic beverages. The accuracy of the method (expressed as average recovery from diverse matrices) is 94.5%, with limits of detection (LODs) ranging between 0.25 and 0.63?µg?l^?1 for different matrices. Benefits such as simplified sample preparation, low detection limits, low solvent consumption and good selectivity render the methodology ideally suited to study the occurrence of EC in diverse commodities. The method was applied to study the occurrence of EC in South African wines, fortified wines and spirits. South African wines, aged 1–9 years, contained 1.8–31?µg?l^?1 EC (RSD?=?69%, n?=?106), fortified wines aged 2–34 years contained 2.8–79?µg?l^?1 EC (RSD?=?89%, n?=?21), and brandies aged 3–20 years contained 4.4–95?µg?l^?1 EC (RSD?=?105%, n?=?26). Factors affecting the formation of EC in these commodities were investigated and storage temperature, alcohol content and pH were found to affect the rate of EC formation. Of these variables storage temperature has by far the greatest effect.     

Levels of selected heavy metals in canned tomato paste sold in Ghana

Sixty-one samples of canned tomato paste comprising seven brands originating from three countries and sold in local markets in the Kumasi Metropolis of Ghana were analysed for levels of iron (Fe), zinc (Zn), manganese (Mn), cadmium (Cd) and lead (Pb) by flame atomic absorption spectrophotometry and for levels of mercury (Hg) by direct mercury analyzer. Mean heavy metal concentrations varied by brand, ranging from below the limit of detection (Cd) to a maximum concentration range of 1.68?±?1.63 to 58.6?±?14.5?µg?g?^?1 (Fe). Estimated mean ranges of other heavy metals are 2.06?±?0.62 to 8.52?±?0.68?µg?g?^?1 (Zn), 2.62?±?0.33 to 5.75?±?0.47?µg?g?^?1 (Mn), 0.070?±?0.003 to 0.116?±?0.012?µg?g?^?1 (Pb) and 0.011?±?0.001 to 0.102?±?0.001?µg?g?^?1 (Hg). Assessed metal levels in five brands were below the WHO/FAO permissible levels. Results of the one-way analysis of variance (ANOVA) conducted on the data suggested no significant variations (P?>?0.05) in the concentrations of the metals in the same brands of canned tomatoes.     

Toward a criterion for suspect thiouracil administration in animal husbandry

Thyreostats are growth-promoters banned in Europe since 1981. The identification of thiouracil (TU) in animal biological matrices can, however, no longer be systematically interpreted as a consequence of illegal administration. Indeed, some experimental results have indicated a causal link between cruciferous-based diet and the presence of TU in urine of bovines. The present study aims at investigating, on a large scale (n?>?1300), the natural occurrence of thiouracil in urine samples collected from different animal species. TU was identified in main breeding animal species: bovine, porcine and ovine. The natural distribution of TU allowed proposing threshold values to differentiate compliant from suspect urine samples. Suggested values are 5.7 and 9.1?µg?l^?1 in male adult bovines (6–24?months), 3.1 and 8.1?µg?l^?1 in female adult bovines (6–24 months), 7.3 and 17.7?µg?l^?1 in calves (<6 months), 3.9 and 8.8?µg?l^?1 in female bovines (>24 months), and 2.9 and 4.1?µg?l^?1 in porcines at a 95 and 99% confidence level, respectively.     

Development and validation of an indirect competitive enzyme-linked immunosorbent assay for monitoring quinoxaline-2-carboxylic acid in the edible tissues of animals

The feed drug additive carbadox is a suspected carcinogen and mutagen. To monitor effectively residues of carbadox in the edible tissues of food-producing animals, an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) to detect quinoxaline-2-carboxylic acid, the marker residue of carbadox, was developed. Several haptens were synthesised and conjugated to the carrier protein. Nine female New Zealand white rabbits were immunised with the immunising conjugates to produce polyclonal antibodies according to the designed schemes of immunisation. The highly specific antibody that was very sensitive to N-butylquinoxaline-2-carboxamide with an IC₅₀ value of 7.75?µg?l^?1 was selected for the development of an ic-ELISA. The standard curves based on the N-butylquinoxaline-2-carboxamide matrix calibration ranged from 0.2 to 51.2?µg?l^?1. The decision limit and detection capability of the ic-ELISA were 0.60 and 0.83?µg?kg^?1 for liver and 0.68 and 0.79?µg?kg^?1 for muscle of swine, respectively. The recoveries were 57–108% with coefficients of variation of less than 20% when the quinoxaline-2-carboxylic acid was spiked into liver and muscle with the concentrations of 1.0–20.0?µg?kg^?1. Excellent correlations between the results of the ic-ELISA and an HPLC method (r?=?0.9956???0.9969) were observed for incurred tissues. These results suggest that the ic-ELISA is a sensitive, accurate and low-cost method that would be a useful tool for screening residues of carbadox in the edible tissues of food-producing animals.     

Chemical composition and in vitro antioxidant studies on Syzygium cumini fruit

Syzygium cumini, widely known as Jamun, is a tropical tree that yields purple ovoid fleshy fruit. Its seed has traditionally been used in India for the treatment of diabetes. Based on the available ethno‐pharmacological knowledge, further studies were extended to understand the chemical composition and antioxidant activities of three anatomically distinct parts of fruit: the pulp, kernel and seed coat. Fruit parts, their corresponding ethanol extracts and residues were evaluated for chemical composition. The alcoholic extract was evaluated for its antioxidant potential against DPPH^?, OH^?, O₂^?? and lipid peroxidation. The whole fruit consisted of 666.0 ± 111.0 g kg^?1 pulp, 290.0 ± 40.0 g kg^?1 kernel and 50.0 ± 15.0 g kg^?1 seed coat. Fresh pulp was rich in carbohydrates, protein and minerals. Total fatty matter was not significant in all three parts of fruit. Detailed mineral analysis showed calcium was abundant in all fruit parts and extracts. Total phenolics, anthocyanins and flavonoid contents of pulp were 3.9 ± 0.5, 1.34 ± 0.2 and 0.07 ± 0.04 g kg^?1, respectively. Kernel and seed coat contained 9.0 ± 0.7 and 8.1 ± 0.8 g kg^?1 total phenolics respectively. Jamun pulp ethanol extract (PEE), kernel ethanol extract (KEE) and seed coat ethanol extract (SCEE) showed a high degree of phenolic enrichment. DPPH radical scavenging activity of the samples and standards in descending order was: gallic acid > quercetin > Trolox > KEE > BHT > SCEE > PEE. Superoxide radical scavenging activity (IC₅₀) of KEE was six times higher (85.0 ± 5.0 µg mL^?1) compared to Trolox (540.0 ± 5.0 µg mL^?1) and three times compared to catechin (296.0 ± 11.0 µg mL^?1). Hydroxyl radical scavenging activity (IC₅₀) of KEE was 151.0 ± 5.0 µg mL^?1 which was comparable with catechin (188.0 ± 6.0 µg mL^?1). Inhibition of lipid peroxidation of the extracts was also studied and their activity against peroxide radicals were lower than that of standard compounds (BHT, 79.0 ± 4.0 µg mL^?1; quercetin, 166.0 ± 13.0 µg mL^?1; Trolox, 175.0 ± 4.0 µg mL^?1; PEE, 342.0 ± 17.0 µg mL^?1; KEE, 202.0 ± 13.0 µg mL^?1 and SCEE, 268.0 ± 13.0 µg mL^?1. Copyright © 2007 Society of Chemical Industry     

Deoxynivalenol exposure assessment in a cohort of pregnant women from Bradford,UK

Deoxynivalenol (DON) is a ubiquitous contaminant of cereal crops in temperate regions of the world. It causes growth faltering and immune suppression in animals. Limited information is available on DON exposure in UK subpopulations. The objective of this study was to provide DON exposure assessment in a subset of pregnant women scheduled for an elective caesarean in a large multi-ethnic mother/infant birth cohort from Bradford, UK. Women aged 16–44 years (n?=?85) provided a urine sample for DON analysis in the last trimester of pregnancy, and concurrently completed a food-frequency questionnaire (FFQ). The urinary DON biomarker was detected in all measured samples (geometric mean (GM)?=?10.3?ng?DON?mg^?1 creatinine, range?=?0.5?116.7?ng?mg^?1). Levels were higher in women classified as South Asian in origin (GM: 15.2?ng?mg^?1; 95% CI?=?10.7?21.5?ng?mg^?1) compared with non-South Asians (GM?=?8.6?ng?mg^?1; 95% CI?=?6.6?11.8?ng?mg^?1), p?=?0.02). Estimated DON intake from FFQ data and typical levels of DON contamination of food suggest that this was mainly due to higher levels of exposure from bread, particularly daily intake of DON from chapattis in South Asians (estimated mean?=?2.4?µg?day^?1; 95% CI?=?1.2, 3.7?µg?day^?1) compared with non-South Asians (estimated mean?=?0.2?µg?day^?1; 95% CI?=?0?0.4?µg?day^?1), p?<?0.001. This is the first biomarker demonstration of DON exposure in pregnant women, and several urinary DON levels were the highest ever recorded in any study. A larger survey within this birth cohort is warranted to investigate any potential risk to mothers and their babies, from DON exposure during pregnancy.     

Occurrence and stability of inorganic and organic arsenic species in wines,rice wines and beers from Central European market

We investigated in total 80 wine samples of different types and seven grape juice and 23 beer samples purchased from markets in Central Europe in order to understand the arsenic (As) speciation and help assess the potential As toxicity via intake of alcoholic beverages. Generally, total As concentrations in most samples investigated were below the drinking water limit 10?µg?l^?1 published by the World Health Organization (WHO); ranging from 0.46 to 21.0?µg?l^?1 As in red and white wines and from 0.75 to 13.4?µg?l^?1 As in beers. In addition, concentrations of total As in rice wine and in rice beer were 0.63–6.07 and 3.69–8.23?µg?l^?1 As, respectively. The total As concentrations in ice wine ranged from 7.94 to 18.8?µg?l^?1 As, significantly higher than in white and red wine. Arsenite predominated as the As species in most of the wine samples, whereas arsenate was the dominant species in rice wine, beer and rice beer. Methyl As components were usually minor components in all wine and beer samples. Monomethylarsonic acid, dimethylarsinic acid and two additional unknown As species were frequently found in grape juice, late harvest and ice wine with higher sweetness. After air exposure, arsenite, arsenate, monomethylarsonic acid and dimethylarsinic acid were stable at 4°C for months, probably due to the acidic conditions of wine and beer samples. The presence of sulfite had little influence on As speciation in wine. Despite the predominance of more toxic arsenite and arsenate in wine and beer, the estimated weekly exposure to As (via consumption of beer, wine and rice wine) is low. The As intake per capita is 6.81?µg from beer, <1.93?µg from wine and 0.88?µg from rice wine, estimated using the median of total As concentration multiplied by the average consumption per capita of the corresponding beverage.     

Ultra-high performance liquid chromatography coupled to triple quadrupole mass spectrometry detection of naturally occurring thiouracil in urine of untreated livestock,domesticated animals and humans

Thiouracil belongs to the xenobiotic thyreostats, which are growth-promoting agents illegally used in animal production. Recently it has been reported that thiouracil is suspected to have a natural origin. The European Union of Reference Laboratory guidance paper of 2007 acknowledged this by stating that thiouracil concentrations below 10?µg?l^?1 might have a natural origin derived from the consumption of Brassicaceae. The present research aimed at endorsing this possible natural occurrence. Urine samples of animals (livestock and domesticated) with known and unknown clinical backgrounds were analysed for thiouracil with a newly developed ultra-high performance liquid chromatography coupled to a triple quadrupole mass spectrometric analysis method without derivatisation. In addition, a small-scale 9-day human experiment with Brassicaceae vegetables was performed to investigate if this natural prevalence could be extrapolated to the human population. The untreated animals had thiouracil concentrations below 10?µg?l^?1 acknowledging the alleged natural occurrence of thiouracil. As for the humans, in 66.7% of the urine samples thiouracil was found above the CC_α of 2.2?µg?l^?1. However, the correlation with the Brassicaceae diet proved to be non-significant (p?=?0.095). Nevertheless, these results clearly demonstrate the natural occurrence of thiouracil in urine of animals and humans. The exact origin of this natural thiouracil trace still needs to be identified.     

Dietary acrylamide exposure among Finnish adults and children: the potential effect of reduction measures

A deterministic exposure assessment using the Nusser method that adjusts for within-subject variation and for nuisance effects among Finnish children and adults was carried out. The food consumption data covered 2038 adults (25–74 years old) and 1514 children of 1, 3 and 6 years of age, with the data on foods’ acrylamide content obtained from published Finnish studies. We found that acrylamide exposure was highest among the 3-year-old children (median?=?1.01?µg?kg^?1?bw^?day^?1, 97.5th percentile?=?1.95?µg?kg^?1?bw^?day^?1) and lowest among 65–74-year-old women (median?=?0.31?µg?kg^?1?bw^?day^?1, 97.5th percentile?=?0.69?µg?kg^?1?bw^?day^?1). Among adults, the most important source of acrylamide exposure was coffee, followed by casseroles rich in starch, then rye bread. Among children, the most important sources were casseroles rich in starch and then biscuits and, finally, chips and other fried potatoes. Replacing lightly roasted coffee with dark-roasted, swapping sweet wheat buns for biscuits, and decreasing the acrylamide content of starch-based casseroles and rye bread by 50% would result in a 50% decrease in acrylamide exposure in adults. Among children, substituting boiled potatoes for chips and other friend potatoes and replacing biscuits with sweet wheat buns while lowering the acrylamide content of starch-based casseroles by 50% would lead to acrylamide exposure that is only half of the original exposure. In conclusions, dietary modifications could have a large impact in decreasing acrylamide exposure.     

Immunoaffinity chromatography purification and ultra-high-performance liquid chromatography-tandem mass spectrometry determination of four β-agonists in beef

A highly selective and sensitive method was developed for the simultaneous determination of four β-agonists (clenbuterol, salbutamol, ractopamine and terbutaline) in beef by immunoaffinity chromatography purification coupled to ultra-high-performance LC-MS/MS. The MS/MS conditions, ultra-high-performance LC mobile phase, injection solution, sample purification process and matrix effect were studied to optimise the operation conditions. The limits of detection (LODs) of the instrument for the studied β-agonists ranged from 0.20 to 0.25?µg?l^?1, and the LODs of the method for the studied β-agonists ranged from 0.20 to 3.00?µg?kg^?1 for beef. Calibration curves were constructed using a standard solution diluted with blank beef matrix. The linear ranges of the calibration curves ranged from 5 to 100?µg?kg^?1 and the coefficients of determination were >0.9942 (n?=?10) for all four β-agonists. Samples spiked at 5, 10 and 50?µg?kg^?1 showed recoveries >72% and RSDs <6.6%. The method is suitable for the simultaneous detection of four β-agonists at trace levels in beef.     

Herbicide contamination of live armclad rockfish,clam and pen shell by moss-control agents used in aquariums of seafood restaurants in Korea

Determination of simazine and diuron by high-performance liquid chromatography-ultraviolet detection (HPLC-UV) in moss-control agents, seawater and fish in aquariums was investigated and validated. The detection limits are 0.2 (simazine) and 0.4?µg l^–1 (diuron) in blank seawater, and 0.20 (simazine) and 0.30 µg kg^?1 (diuron) in blank fish homogenate, while the recoveries ranged from 93.9% to 102.4% with a relative standard deviation?≤?9.8% for simazine and diuron. The method was successfully used in the study of simazine and diuron contamination in live fish stored in seafood restaurant aquaria in Korea. It was found that 0.4–2.3% of simazine and <0.10–3.8% of diuron were included the in moss-control agents tested. Of the 66 sampled aquarium seawaters, simazine was found to be present in four samples (3.8–42?µg?l^?1) while diuron was detected in two samples (1.3–1.6?µg?l^?1). For fish homogenates used in a bioconcentration study, simazine content ranges from 0.17 to 1.8?mg?kg^?1.     

Voltammetric analysis of DL‐α‐tocopherol with a paste electrode

BACKGROUND: A voltammetric study of vitamin E (DL‐ α‐tocopherol) detection using square wave stripping and cyclic voltammetry is discussed in this paper. The working sensor was made by mixing carbon nanotube powder with DNA (double‐stranded calf thymus DNA) and mineral oil. In this electrode, the anodic peak was obtained for ? 0.6 V in a 0.1 mol L^?1 phosphate electrolyte solution. RESULTS: Under optimized stripping conditions, analytical linear working ranges of 0.5–4.0 µg L^?1 and 40.0–160.0 µg L^?1 were obtained. The RSD precision was pegged at 0.105% with seven points using an 80 µg L^?1 spike. The detection limit (S/N) was found to be 0.056 µg L^?1 (1.30 × 10^?10 mol L^?1). CONCLUSION: The developed method was found to be applicable to quality control analysis in the food, pharmaceutical and other manufacturing sectors. Copyright © 2008 Society of Chemical Industry     

Contribution of water and cooked rice to an estimation of the dietary intake of inorganic arsenic in a rural village of West Bengal,India

Arsenic contamination of rice plants by arsenic-polluted irrigation groundwater could result in high arsenic concentrations in cooked rice. The main objective of the study was to estimate the total and inorganic arsenic intakes in a rural population of West Bengal, India, through both drinking water and cooked rice. Simulated cooking of rice with different levels of arsenic species in the cooking water was carried out. The presence of arsenic in the cooking water was provided by four arsenic species (arsenite, arsenate, methylarsonate or dimethylarsinate) and at three total arsenic concentrations (50,?250 or 500?µg?l^?1). The results show that the arsenic concentration in cooked rice is always higher than that in raw rice and range from 227 to 1642?µg?kg^?1. The cooking process did not change the arsenic speciation in rice. Cooked rice contributed a mean of 41% to the daily intake of inorganic arsenic. The daily inorganic arsenic intakes for water plus rice were 229, 1024 and 2000?µg?day^?1 for initial arsenic concentrations in the cooking water of 50, 250 and 500?µg?arsenic?l^?1, respectively, compared with the tolerable daily intake which is 150?µg?day^?1.     

Survey of T-2 and HT-2 toxins by LC–MS/MS in oats and oat products from European oat mills in 2005–2009

T-2 and HT-2 toxins were analysed in oats (n?=?243), oat flakes (n?=?529), oat meal (n?=?105) and oat by-products (n?=?209) from 11 European mills during 2005–2009 by high-performance liquid chromatography with a triple quadrupole mass spectrometer. Limits of quantification were 5?µg?kg^?1 for both T-2 and HT-2 toxins in oats. The incidence of T-2?+?HT-2 (>5?µg?kg^?1) in oats, oat flakes, oat meal and oat by-products was 93, 77, 34 and 99%, respectively. The mean values of T-2?+?HT-2 were 94, 17, 11 and 293?µg?kg^?1 for oats, oat flakes, oat meal and oat by-products, respectively. T-2 and HT-2 occurred together and the T-2 level was 52% of HT-2 in oats. Maximal T-2 and HT-2 concentration in oat flakes and oat meal were 197 and 118?µg?kg^?1. The toxins were reduced by 82–88% during processing, but increased 3.1 times in oat by-products.