Multiple mycotoxins in commonly used edible oils: Occurrence and evaluation of potential health risks.

In this study, the contamination of 51 mycotoxins in 416 edible oils were determined by UPLC-MS/MS. Totally, twenty-four mycotoxins were detected and nearly half of the samples (46.9%, n = 195) were contaminated simultaneously with six to nine kinds of mycotoxins. The predominant mycotoxins and contamination characteristics varied depending on the type of oils. More specifically, four enniatins, alternariol monomethyl ether (AME) and zearalenone were the most frequent combination. Overall, peanut and sesame oils (10.7-11.7 mycotoxins on average) were found to be the most contaminated matrices whereas camellia and sunflower seed oils (1.8-2.7 species) were the opposite. Dietary exposure risks of mycotoxins were acceptable in most cases, however, the ingestion of aflatoxins (especially aflatoxin B1) through peanut and sesame oil (margin of exposure: 239.4-386.3 < 10000) exceeded the acceptable carcinogenic risk level. Meanwhile, the risks of cumulative ingestion through the food chain should be of great concern, especially sterigmatocystin, ochratoxin A, AME and zearalenone.

Contamination status of bisphenol A and its analogues (bisphenol S, F and B) in foodstuffs and the implications for dietary exposure on adult residents in Zhejiang Province.

An effective method has been developed for the simultaneous determination of four bisphenols (bisphenol A, S, F and B) in various foodstuffs. The contaminants were extracted by QuEChERS-based strategy and subjected to ion-exchange solid-phase extraction for further clean-up. The critical variables were screened by Plackett-Burman design and then optimized by central composite design. Under the optimized conditions, satisfactory accuracy (recoveries 76%-116%) and precision (RSDs < 12%) were achieved. The established method was then used to assess the contamination status of 379 real samples. Bisphenol A was demonstrated to be the predominant bisphenol with highest incidence (79.7%) and average concentration (14.3 µg/kg). The positive rates (mean concentration) of bisphenol S, F and B were 37.7% (1.6 µg/kg), 26.9% (1.4 µg/kg) and 0.0% (not detected), respectively. Finally, the daily dietary intakes of ∑4bisphenolsfor adult residents were estimated (55.9-76.1 ng/kg bw/day) according to the contamination concentrations and the daily recommended intakes.

A feasibility study of producing a peanut oil matrix candidate reference material and its application to support monitoring of aflatoxins statues for public health purposes.

The first peanut oil reference materials in naturally contaminated aflatoxins was developed, because of the high consumption of this product and the potential risk associated herewith. Based on liquid chromatographic method, homogeneity, short-term of 60 °C for seven days and long-term of 25 °C for twelve months' stability studies of candidates were assessed. The obtained data and statistical results showed a successful feasibility study, without any significant trend. Nine selected expert laboratories were invited to certify the contents of candidates using distinguish quantitative liquid chromatographic method. The certified values and expanded uncertainties (k = 2) for these two batches were 6.5 ±â€¯1.6 µg/kg, 29.3 ±â€¯5.3 µg/kg for aflatoxin B1; 1.2 ±â€¯0.3 µg/kg, 5.2 ±â€¯0.9 µg/kg for aflatoxin B2; 5.0 ±â€¯0.4 µg/kg, 8.4 ±â€¯0.7 µg/kg for aflatoxin G1; and 2.1 ±â€¯0.2 µg/kg, 3.5 ±â€¯0.2 µg/kg for aflatoxin G2, respectively.

Fast and quantitative determination of saxitoxin and neosaxitoxin in urine by ultra performance liquid chromatography-triple quadrupole mass spectrometry based on the cleanup of solid phase extraction with hydrophilic interaction mechanism.

Saxitoxin (STX) and neosaxitoxin (NEO) are water-soluble toxins and their cleanup in bio-matrix is a hot topic but difficult problem. A fast and quantitative determination method for STX and NEO in urine was developed using ultra performance liquid chromatography-triple quadrupole mass spectrometry (LC-MS/MS) based on the cleanup of solid phase extraction (SPE) with hydrophilic interaction (HILIC) mechanism. Acetonitrile/methanol/water mixture was used to extract the toxins in urine. Polyamide (PA) was used as HILIC SPE material to clean the toxins in sample matrix. The limits of detection were 0.2ngmL-1 for STX and 1ngmL-1 for NEO in urine. The linear ranges were 0.5ngmL-1-99.2ngmL-1 with the correlation coefficient of r=0.9992 for STX and 2.1ngmL-1-207ngmL-1 with r=0.997 for NEO in urine matrix. The recoveries at three spiking levels were 81.5%-117% with the relative standard deviations (RSDs) of 5.4%-8.5% for STX and 89.0%-118% with the RSDs of 6.7%-9.1% for NEO. STX was found in all the 6 patients' urines while NEO was only found in one sample from an intoxication case.

Optimization for quick, easy, cheap, effective, rugged and safe extraction of mycotoxins and veterinary drugs by response surface methodology for application to egg and milk.

A multiclass method was proposed for the simultaneous determination of various classes of veterinary drugs (n = 65), mycotoxins and metabolites (n = 39) in egg and milk by ultra-high performance liquid chromatography-tandem mass spectrometry. The contaminants were extracted by QuEChERS-based strategy including salt-out partitioning and dispersive solid-phase extraction for cleanup further. With the aim of maximizing throughput and extraction efficiency, Plackett-Burman design was employed initially for screening significant variables. And response surface methodology based on central composite design was conducted to achieve optimal conditions in details: 3.35% (v/v) of formic acid in acetonitrile, 1.2 g of NaCl, 0.5 g of anhydrous NaAc, 300 mg of C18 and 140 mg of primary secondary amine. Satisfactory analytical characteristics in validation, in aspects of accuracy (70%-105% for mycotoxins and quinolones, 55%-80% for sulphonamides and 40%-105% for other veterinary drugs), precision (inter-day RSDs < 14%) and sensitivity (LOQs ranged from 0.01 µg/kg to 31 µg/kg), were achieved under the optimized conditions. The matrix effects were evaluated and compensated by the use of matrix-matched calibration curves (R2 > 0.987). In practice, 45 eggs and 30 milk samples were investigated by the established method, of which positive finding aflatoxin in milk and sterigmatocystin in eggs.

Simultaneous determination of five Alternaria toxins in cereals using QuEChERS-based methodology.

Two analytical approaches, including ultra-high performance liquid chromatograph linked with photo-diode array/fluorescence detector, and ultra-high performance liquid chromatography-tandem mass spectrometry, have been proposed for simultaneous determination of five Alternaria toxins in cereals, which both based on QuEChERS strategy. After QuEChERS extraction and salting out, the collected supernatant was subjected to an extra dispersive liquid-liquid microextraction step prior to quantitative analysis. Response surface methodology based on central composite design was employed to optimize the micro-extraction conditions. During photo-diode array/fluorescence detector method validation, satisfactory analytical characteristics, in terms of selectivity, recovery (72.7%-109.1%), precision (inter-day RSDs <9.6%), sensitivity (limits of quantification ranged from 2.1µgkg-1 to 120.0µgkg-1) and linearity (R2 all higher than 0.9984), were achieved. Mass spectrometry method was employed as a certified method for accuracy. The two methodologies were successfully applied to 71 samples including three different matrices and the quantitative results were compared. As the result of non-parametric test shown, the established two analytical approach exhibited comparable quantitative accuracy to each other.

High-performance liquid chromatographic determination of multi-mycotoxin in cereals and bean foodstuffs using interference-removal solid-phase extraction combined with optimized dispersive liquid-liquid microextraction.

A novel pre-treatment was proposed for the simultaneous determination of aflatoxins, ochratoxin A and zearalenone in foodstuffs using high-performance liquid chromatography with fluorescence detection. The analytical procedure was based on a first step using a quick, easy, cheap, effective, rugged, and safe based extraction procedure, followed by salting out and purification with a C18 solid-phase extraction column as interference removal clean-up. Subsequently, collected supernatant was subjected to dispersive liquid-liquid microextraction. Response surface methodology based on central composite design was employed to optimize conditions in the microextraction procedure. Under the optimum conditions, satisfactory analytical performance with recoveries ranging from 63.22 to 107.6% were achieved in different types of cereals and beans, as well as desirable precisions (0.81-8.13%). Limits of detections and quantifications for these six mycotoxins ranging from 0.03 to 13 µg/kg and 0.22 to 44 µg/kg, respectively, were obtained. Finally, the established method was successfully validated by four certified reference materials (P = 0.897 > 0.05) and applied to 79 samples from local markets.

Analysis of monofluoroacetic acid in urine by liquid chromatography-triple quadrupole mass spectrometry and preparation of the positive sample by the bioconversion from monofluoroacetamide to monofluoroacetic acid in vitro.

Whether as a rodenticide or as a natural product, monofluoroacetic acid (FAcOH) may cause poisoning to humans or animals for its high acute toxicity. Urine is one of the most typical specimens for forensic diagnosis when poisoning case about FAcOH happens. The positive sample containing FAcOH plays a key role for the development of an accurate and reliable analytical method. The bioconversion from monofluoroacetamide (FAcNH2) to FAcOH in urine in vitro was studied for the preparation of positive urine sample containing FAcOH without standard spiking or animal experiment. The average bioconversion rates were 0%, 18.6% and 41.3% when incubated the FAcNH2 spiked urine in vitro for 21days at -20°C, room temperature (RT) and 37°C, respectively. Afterwards, a fast and sensitive analytical method was developed for determination of FAcOH in urine. Samples were diluted with water containing formic acid and cleaned with polymeric anion exchange (PAX) cartridge. The acid eluate was neutralized with ammonium hydroxide and directly measured by hydrophilic interaction liquid chromatography-triple quadrupole mass spectrometry (LC-MS/MS) using basic mobile phase condition. The limit of detection and limit of quantification of FAcOH in urine were 2 and 5ngmL(-1), respectively. The linear range was 5-1000ngmL(-1) with a correlation coefficient of r=0.9993 in urine calibrated with internal standard. The recoveries at four spiking levels (5, 10, 50 and 500ngmL(-1) in urine) were 87.2%-107% with relative standard deviations ranged between 4.3%-8.8%.

Simultaneous and rapid determination of deoxynivalenol and its acetylate derivatives in wheat flour and rice by ultra high performance liquid chromatography with photo diode array detection.

A simple and reliable method of ultra high performance liquid chromatography coupled with photo-diode array detection has been proposed for the simultaneous determination of deoxynivalenol and its acetylated derivatives in wheat flour and rice, especially focusing on the optimization of sample extraction, cleanup, and chromatographic separation conditions. Sample pretreatment consisted of a first step using a quick, easy, cheap, effective, rugged, and safe based extraction procedure and a subsequent cleanup step based on solid-phase extraction. The method was extensively validated in wheat flour and rice, obtaining satisfactory analytical performance with good linearity (R(2) ≥ 0.999), acceptable recoveries (80.0-104.4%), and repeatability (RSDs 1.3-10.7%). The limits of detection (21.7-57.4 µg/kg) and quantitation (72.3-191.4 µg/kg) for deoxynivalenols were lower than those usually permitted by various countries' legislation in these food matrices. The method was applied to 34 wheat and rice samples. The results were further compared with results of ultra high performance liquid chromatography with electrospray ionization tandem mass spectrometry.

[Effects of hemoperfusion on the patients with acute toxication of 2, 4-dinitrophenol].

OBJECTIVE: To explore the management strategies of acute toxication of 2, 4-dinitrophenol by hemoperfusion. METHODS: A total of 14 patients with acute toxication of 2, 4-dinitrophenol were admitted on September 14, 2009. And they were divided into severe and mild groups according to the severity of clinical manifestation. All patients in both groups received 2-hour blood perfusion within 2 hour post-admission. Their clinical manifestations, laboratory parameters and 2, 4-dinitrophenol levels were carefully observed before and after each perfusion. And oxygenation, intravenous use of furosemide, corticosteroids and symptomatic therapies were simultaneously given to improve general conditions. RESULTS: In serious group, the levels of before and after the first perfusion were 28.21(15.56-45.23) and 16.11(10.10-27.52) mg/L (P < 0.05), respectively. In both groups, all levels of 2, 4-dinitrophenol were significantly reduced before and after each perfusion (all P < 0.05). The patients in severe group would get relieved after 3 vs 2 perfusions in mild group. In severe group, there was a remarked decrease in neutrophil and platelet count after perfusion than those in mild group. The liver enzymes and blood lipids in both groups after therapy significantly elevated than those before therapy (all P < 0.05). CONCLUSION: Crucial for managing acute toxication of 2, 4-dinitrophenol, early hemoperfusion reduces mortality.

Multi-residue analysis of pesticides in tea by online SEC-GC/MS.

A multi-residue method for the analysis of pesticides in tea was developed by online size exclusion chromatography (SEC)-GC/MS with full scan mode. The sample was fortified with chlorpyrifos-d(10) isotope internal standard and extracted by acetonitrile. After purification by primary secondary amine sorbent and solvent exchange by SEC mobile phase, the sample was detected by online SEC-GC/MS. The purification result of the online system was evaluated by comparing the correlation between Chinese cabbage and tea matrix. The factors for method optimization included sample preparation, matrix effects and the instrument parameters of each online component. Scatter plot was introduced in this study to directly illustrate the results of the condition optimization and matrix effects in the online system. For most of the pesticides, the average recoveries ranged from 70 to 130% and the RSD were below 15%. The feasibility of the application of full scan mode in multi-residue determination of trace amounts of pesticides (LODs below 0.01 mg/kg) in a complex matrix was discussed.

Direct determination of melamine in dairy products by gas chromatography/mass spectrometry with coupled column separation.

A coupled capillary column system was developed for the qualitative and quantitative determination of melamine with isotope internal standard in dairy products by gas chromatography/mass spectrometry (GC/MS) without derivatization. A 30 m of DB-5 ms ((5%-phenyl)-methylpolysiloxane, 0.25 mm i.d., 0.25 microm df) coupled with a 1.5 m of Innowax (polyethylene glycol, 0.32 mm i.d., 0.25 microm df) by a quartz capillary column connector was introduced as separation column. Three advantages were discussed for the coupled system. The sample was fortified with a ring-labeled (13)C(3)(15)N(3)-melamine as an isotope internal standard and extracted by 1% of trichloroacetic acid aqueous solution. 2.2% of lead acetate solution was then added to deposit protein in the sample matrix. After purification by cation exchange cartridge, the sample solution was directly injected and detected by GC/MS. A six-point calibration curve ranging from 0.05 to 2 mg kg(-1) of melamine in sample was used to establish instrument response. The recovery was 93.9-102% with relative standard deviation from 3.1 to 8.7% when isotope internal standard used. The calculated method detection limit was 0.01 mg kg(-1).

A microfluidic chip based liquid-liquid extraction system with microporous membrane.

A robust and simple approach for microfabricated chip based liquid-liquid extraction was developed for on-chip sample pretreatment. The chip based extraction system was composed of two microfabricated glass plates with a microporous membrane sandwiched in between. A simple bonding approach using epoxy was used to achieve bonding and sealing of the L-L extraction chip. Gravity was employed to drive the aqueous and organic flows through separate channels in the extraction system, separated by the membrane. During extraction, the analyte in an aqueous sample stream was transferred through the membrane into the organic stream. The fluorescence intensity of the analyte extracted into the organic stream was monitored in situ by a laser induced fluorescence detection system. The performance of the system was demonstrated using an aqueous solution of butyl rhodamine B (BRB) and isobutanol as sample and extractant, respectively. The system proved to be an efficient means for achieving chip based microporous membrane liquid-liquid extraction. The precision of fluorescence measurements was 1.5% R.S.D. (n=4). A linear response range of 1x10(-7) to 1 x 10(-4) M BRB was obtained with a regression equation: I=8.00 x 10(6) C + 4.91. An enrichment factor of ca. 3 was obtained with an extraction efficiency of 69%.