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1.
A series of twelve breast milk samples were analysed by gas chromatography-mass spectrometry (GC/MS) operated in selected ion monitoring mode for 3-chloropropane-1,2-diol (3-MCPD). Whilst none of the samples contained 3-MCPD above the limit of detection of 3 μg kg?1 milk, all contained high amounts of 3-MCPD esterified with higher fatty acids. The levels of 3-MCPD released by hydrolysis of these esters (bound 3-MCPD) ranged from the limit of detection (300 μg kg?1, expressed on a fat basis) to 2195 μg kg?1; with a mean level of bound 3-MCPD of 1014 μg kg?1, which corresponded to 35.5 μg kg?1 milk. The presence of bound 3-MCPD was confirmed using orthogonal gas chromatography coupled with high-speed time-of-flight mass spectrometry analysis for four randomly selected breast milk samples. Six breast milks collected from one of the nursing mothers 14–76 days after childbirth contained bound 3-MCPD within the range of 328–2078 μg kg?1 fat (mean 930 μg kg?1 fat). The calculated bound 3-MCPD content of these samples was within the range of 6 and 19 μg kg?1 milk (mean of 12 μg kg?1 milk). The major types of 3-MCPD esters were the symmetric diesters with lauric, palmitic, and oleic acids, and asymmetric diesters with palmitic acid/oleic acid among which 3-chloro-1,2-propanediol 1,2-dioleate prevailed.  相似文献   

2.
A method based on headspace-solid phase microextraction and gas chromatography with mass spectrometry has been developed and validated for the determination of benzene in soft drinks. The extraction step was optimized using a rotatable central composite design including the following experimental variables: extraction temperature, extraction time, sample weight, and salt concentration. The optimized procedure, which was carried out at 30 °C during 30 min by using a 75 μm carboxen-polydimethylsiloxane fiber, showed good linearity within the concentration range 0–25 μg?kg?1 (r 2 ?>?0.999), mean recoveries from 97.5 to 103.1 %, and coefficients of variation from 1.5 to 13.4 % for repeatability and from 1.5 to 15.7 % for within-laboratory reproducibility. Limits of detection and quantification were calculated at 0.02 and 0.08 μg?kg?1, respectively. The method was applied to determine the concentrations of benzene in 77 samples of beverages from the Brazilian market. Levels from <0.08 to 10.84 μg?kg?1 were obtained, which are comparable to those verified in other countries. Most of the samples (72.2 %) contained benzene up to 1 μg?kg?1.  相似文献   

3.
A highly sensitive analytical method was developed to determine 2,4,6-trichloroanisole (TCA), 2,3,4,6-tetrachloroanisole (TeCA), 2,4,6-tribromoanisole (TBA) and 2,3,4,5,6-pentachloroanisole (PCA) in sparkling alcoholic beverages. The method was based on the use of headspace solid-phase microextraction (HS-SPME) using a polydimethylsiloxane (PDMS) fibre. It was coupled to gas chromatography-triple quadrupole tandem mass spectrometry (GC-QqQ-MS/MS) for the detection and quantification of the target haloanisoles. The method was fully automated and no sample preparation was needed. The method was validated for alcoholic beverages. The influence of CO2 on the extraction efficiency was also evaluated for the studied sparkling drinks (cava and cider). All the calibration curves showed good linearity (R2 0.98) within the tested range (1–50 ng l?1). Recoveries were evaluated at three different levels (1, 5 and 50 ng l?1) and were always between 71% and 119%. Precision was expressed as relative standard deviation (RSD), and was evaluated as intra- and inter-day precisions, with values ≤ 22% in both cases. Limits of quantitation (LOQs) were ≤ 0.91 ng l?1, which are below the sensory threshold levels for such compounds in humans. The validated method was applied to commercial samples, 10 cavas and 10 ciders, but it was also used for the analysis of nine red wines and four white wines, demonstrating the further applicability of the proposed method to non-sparkling beverages. TCA was detected in most samples at up to 0.45 ng l?1.  相似文献   

4.
Thirty-seven different samples of canned sardines and other fish sold in the United Kingdom were analysed for their furan content using a validated automated headspace gas chromatography–mass spectrometry procedure. All 37 samples contained detectable furan, with an average level of 26 μg kg?1. The maximum furan content was in canned fish containing tomato sauce, which had an average of 49 μg kg?1 and in canned fish packed with lemon which had an average of 55 μg kg?1. All fish in brine or in oil contained less than 20 μg kg?1 furan. Furan levels recorded in fish packed in extra virgin olive oil were low with an average of 2 μg kg?1.  相似文献   

5.
Surveys of major Brazilian foodstuffs demonstrated that peanuts and peanut products continue to be very susceptible to aflatoxin contamination. To prevent, or at least minimise, the problem the aflatoxins need to be monitored by a rapid and inexpensive screening method. The AOAC Romer method has been used and found highly reliable. However, the clean-up step utilises anhydrous FeCl3 and basic CuCO3 which are expensive and not readily available in Brazil. Thus, the extraction (with a mixture of 270 ml methanol plus 30ml 40 g litre?1 aqueous KCl) and clean-up (150 ml 100 g litre?1 aqueous CuSO4) steps of the method of Soares and Rodriguez-Amaya (1985) were combined with the AOAC minicolumn to provide a rapid, inexpensive screening technique. Fifty-two sample lots of peanuts and peanut products were screened by this and Romer's method, and the results were in complete agreement: 28 samples were negative, four < 20 μg kg?1, 12 in the range 20–50 μg kg?1, three in the range 50–100 μg kg?1 and 5 >100 μg kg?1. The results also agreed well when the extracts obtained by the two methods were submitted to quantitative TLC.  相似文献   

6.
Selectivity of solid-phase extraction (SPE) was combined with the concentration power of dispersive liquid–liquid microextraction (DLLME) to obtain a sensitive, low solvent consumption method for high-performance liquid chromatography determination of diazinon and chlorpyrifos in rice. In this method, rice samples were extracted by ultrasound-assisted extraction followed by SPE. Then, the SPE eluent was used as a disperser solvent in the next dispersive liquid-liquid microextraction step for further purification and enrichment of diazinon and chlorpyrifos. Under the optimal conditions, the linear range was from 5.0 to 250 μg kg?1 for diazinon and from 2.5 to 250 μg kg?1 for chlorpyrifos. Limits of detection of diazinon and chlorpyrifos were 1.5 and 0.7 μg kg?1, respectively. Limits of quantitation of diazinon and chlorpyrifos were 5.5 and 3.0 μg kg?1, respectively. The precisions and recoveries also were investigated by spiking 10 μg kg?1 concentration in rice. The recoveries obtained were over 90 % with relative standard deviation (RSD%) below 9.0 %. The new approach was utilized to successfully detect trace amounts of diazinon and chlorpyrifos in different Iranian rice samples.  相似文献   

7.
We describe an automatic method to detect formaldehyde (FA) in some fermented foods. This method is based on derivatisation with 2,2,2‐trifluoroethylhydrazine (TFEH) and consecutive headspace solid‐phase micro‐extraction and gas chromatography‐mass spectrometry. FA in food reacted for 30 min at 40 °C with 2,2,2‐TFEH in a headspace vial, and the formed FA‐TFEH derivative was simultaneously vaporised and adsorbed on 85‐μm carboxen–polydimethylsiloxane. Under the established condition, the limit of detection was 0.1 μg kg?1 by using 1.0‐g solid food and 1.0‐mL liquid food, and the relative standard deviation was less than 10% at FA concentrations between 0.050 and 0.500 mg kg?1. The concentrations of FA in several traditional Korean foods including gimchi, watery radish gimchi, soybean paste, red pepper paste, soy sauce and bean‐paste soup were measured. All food samples had detectable levels of FA (0.104–13.05 mg kg?1).  相似文献   

8.
An extensive UK survey of styrene monomer levels in styrene based plastic packaging materials and their contained foods (133 samples) has been carried out, examining a wide range of retail foods of different brand names and including yogurts, creams, salads, coleslaws, soft cheeses, margarines, hot and cold beverages from dispensing machines, spreads, fresh and cooked meats, candied fruits, fresh strawberries, and take-away ‘fast’ foods. Analysis by headspace gas chromatography of styrene levels in the plastic containers showed levels of monomer ranging from 16 to 1300 mg kg?1 although the majority of containers (73%) had styrene levels in the range 100–500 mg kg?1 and only five plastic tubs had levels exceeding 1000 mg kg?1. Analysis of the food contents of the plastic containers by automated headspace gas chromatography with single ion monitoring mass spectrometric detection showed levels of the monomer ranging from < 1 μg kg?1 to 200 μg kg?1, although the majority of foods (77%) had styrene levels below 10 μg kg?1, and 26% of the total number analysed had levels below 1 μg kg?1.  相似文献   

9.
A gas chromatography-ion-trap tandem mass spectrometry procedure was developed for the determination of 2,6-diisopropylnaphthalene (DIPN) and n-dibutylphthalate (DBP) in domestic and imported paper packages and food sold in US marketplaces. The procedure involved ultrasonic extraction with dichloromethane, followed by analysis with the gas chromatography-ion-trap tandem mass spectrometry. Calibration curves for DIPN and DBP were achieved with concentrations ranging from 0.01 to 10 µg ml?1 and the corresponding r 2 values were 0.9976 and 0.9956, respectively. In most of the fortified samples the recoveries were higher than 80% with a relative standard deviation (RSD) <10%. Using this procedure, it was found that less than 20% of the tested domestic packages and more than 60% of the tested imported food packages contained both DIPN and DBP. The concentrations of DIPN and DBP ranged from 0.09 to 20 mg kg?1 and 0.14 to 55 mg kg?1, respectively, with most of the DINP and DBP levels lower than 20 mg kg?1. DIPN was not detected (<0.01 mg kg?1) in 41 food samples and DBP was only detected in two domestic and four imported food samples with concentrations ranging from <0.01 to 0.81 mg kg?1.  相似文献   

10.
The natural occurrence of fungi, mycotoxins and fungal metabolites was investigated in 100 samples of maize grains collected from south and southwestern Ethiopia in 2015. The maize samples were contaminated by Fusarium, Aspergillus and Penicillium species. Using liquid chromatography tandem mass spectrometry 127 secondary metabolites were analysed. Zearalenone was the most prevalent mycotoxin, occurring in about 96% of the samples. Zearalenone sulfate was the second most prevalent, present in 81% of the samples. Fumonisin B1 was detected in 70% of the samples with a mean level of 606 μg kg?1 in positive samples, while FB2, FB3 and FB4 were detected in 62%, 51% and 60% of the maize samples with mean levels of 202, 136 and 85 μg kg?1, respectively. Up to 8% of the samples were contaminated with aflatoxins, with a maximum level of aflatoxin B1 of 513 μg kg?1. Results were higher than earlier reports for maize from Ethiopia.  相似文献   

11.
Total mercury (THg) levels in 440 pairs of milled rice samples and brown rice samples from 15 major rice grain-producing provinces of China were measured and the associated health risk via rice consumption for different age categories of Chinese population was also assessed. THg contents were measured by a direct mercury analyser and the limit of detection (LOD) was 1.5 μg kg?1. The THg levels for milled rice samples and brown rice samples varied from non-detected to 17.8 μg kg?1 and 1.5 to 25.4 μg kg?1, respectively, with a mean level of 3.4 μg kg?1 and 4.9 μg kg?1, respectively. The THg levels in all milled and brown rice samples were generally low, except three brown rice samples having concentrations above the legally set value for cereals (20 μg kg?1 Hg). THg intakes for different age categories were estimated according to THg content and corresponding rice consumption and the associated health risk was evaluated by the corresponding provisional tolerable weekly intake (PTWI) for THg (5.0 μg kg?1 bw week?1), which was established by the Joint FAO/WHO Expert Committee on Food Additives (JECFA). The 50th percentile of the THg intakes via milled rice and brown rice consumption for different age categories was in the range 0.09–0.19 μg kg?1 bw week?1 and 0.14–0.27 μg kg?1 bw week?1, respectively, well below the PTWI, suggesting that the associated health risk is relatively low. However, the 99.9th percentile of the THg intakes for 2–4-year-old children amounted up to 20.6% of the PTWI (milled rice) and 29.5% of the PTWI (brown rice), which deserves attention.  相似文献   

12.
An easy‐to‐use and simplified liquid chromatography‐tandem mass spectrometry (LC‐ESI (+)‐MS/MS) method was adopted to determine the amount of acrylamide in thirty‐two samples of potato chips purchased on the South Italian market in 2009. Extract produced from matrices was directly analysed without derivatisation, the use of isotopically labelled acrylamide or the use of clean up cartridges. Quality analytical data were reported. The limit of detection and limit of quantification were 6 μg kg?1 and 18 μg kg?1, respectively and recovery values ranged from 90.7–96.3%. The relative standard deviation (RSD) ranged between 2.1% and 5.8%. The values ranged between 27 and 1400 μg kg?1 and the arithmetic mean acrylamide content resulted 363 μg kg?1. According to Foot et al. [Food Additives and Contaminants, 24 (2007)(S1), 37] and considering 500 μg kg?1 as the minimum level possible with the actual available mitigation tools, the number of samples showing an acrylamide level higher than 500 μg kg?1 resulted to be 22%. This paper gives a contribution to data collection in response to the monitoring activity of EFSA and following the Commission Recommendation 2007/331/EC: really, the number of Italian samples of potato chips and potato products for which acrylamide values was reported in the ‘results on the monitoring of acrylamide’ of EFSA ( http://www.efsa.europa.eu/cs/BlobServer/Report/datex_report_acrylamide_en,0.pdf?ssbinary=true , 2009) issued on 30 April 2009 is very limited.  相似文献   

13.
The purpose of this study was to measure acrylamide (AA) levels and selected parameters of different traditional Turkish coffees. AA, 5-hydroxymethylfurfural (HMF), total reducing sugar, protein, pH, moisture, dry matter (DM) as well as ash, caffeine and soluble solids content (SSC) in DM, L*, a*, b* colour parameters of coffee samples were determined and the correlation between AA level and these parameters were investigated. A total of 36 coffee samples (20 Turkish, 8 Dibek and 8 Terebinth coffee) from the Turkish market were examined. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was validated for the detection and quantitation of AA in coffee samples. The calibration curve was linear (R2 ≥ 0.999) over the range of 30–1000 μg kg?1. The limit of detection (LOD) and limit of quantification (LOQ) were found as 4.6 μg kg?1 and 15.5 μg kg?1, respectively. The amounts of AA in analysed coffee samples were in the range 31.1 ± 0.6 to 323.4 ± 5.4 µg kg?1. The highest mean AA levels were found in Terebinth coffees (240.3 μg kg?1) followed by Turkish coffees (204.3 µg kg?1) and then Dibek coffees (78.6 µg kg?1). No tested Turkish coffee samples had an AA concentration above the indicative value (450 µg kg?1) for roast coffee recommended by the European Commission (EC) in 2011. In addition, a strong positive correlation was found between HMF values and AA amounts of selected coffee types.  相似文献   

14.
The 3-monochloro-1,2-propandiol (3-MCPD) levels in soy sauces which contained hydrolysed vegetable protein were evaluated for the Bulgarian market. For analysis of 3-MCPD, a gas chromatography–mass spectrometry (GC-MS) method was applied with a linear range of 0.03–2.00 μg mL?1 and a limit of detection (LOD) of 2.3 μg kg?1 and a limit of quantification (LOQ) of 3.4 μg kg?1. At these levels, the standard deviation was 5.1%, with recoveries between 81% and 102%. The method was applied to the analysis of 21 samples of soy sauce from the Bulgarian market. Results ranged from 3.7 to 185.6 μg kg?1. Soy sauces produced from hydrolysed soy protein contained higher levels of 3-MCPD than naturally fermented sauces. In 38.4% of samples of Bulgarian origin, the 3-MCPD content was above the EU limit of 20 μg kg?1. In all analysed samples, 33.3% had a 3-MCPD content above the EU limit.  相似文献   

15.
建立了氢氧化钡处理结合二氯甲烷萃取进行样品处理,气相色谱-串联质谱法检测几种水产品和加工肉制品中7种N-亚硝胺的新方法。以N-亚硝基二甲胺-d6、N-亚硝基二正丙胺-d14和N-亚硝基吡咯烷-d8为内标,10 g样品于50 mL离心管中经氢氧化钡溶液一步处理,离心后上清液再经二氯甲烷一次萃取,旋蒸浓缩至5 mL,氮吹至1 mL,DB-WAXUI柱(30 m×250 μm×0. 25 μm)进行色谱分离,多反应监测(MRM)模式进行质谱检测。该方法样品处理简便易行,7种N-亚硝胺在1~100 ng/mL浓度范围内线性良好(R2 > 0. 999);检出限为0.08~0.23 μg/kg,定量限为0.25~0.76 μg/kg;添加回收率为71.6%~133.8%,RSD为2.04%~17.1%。对市售9个鱼虾和8个加工肉制品的实际检测显示,N-亚硝基二甲胺的含量均在安全范围内。  相似文献   

16.
A reliable and sensitive method for simultaneous determination of bisphenol A (BPA) and bisphenol F (BPF) in canned food by gas chromatography-mass spectrometry (GC/MS) is described after extraction and pre-concentration by a new solid-phase microextraction (SPME) adsorbent. The potential of single-walled carbon nanotubes (SWCNTs) as SPME adsorbent for the pre-concentration of environmental contaminants has been investigated in recent years. This work was carried out to investigate the feasibility of SWCNTs as a headspace SPME adsorbent for the determination of bisphenol derivatives in canned food. Potential factors affecting the extraction efficiency, including extraction time, extraction temperature, desorption time, desorption temperature, and salinity were optimized. Calibration curves were linear (r 2≥ 0.994) over the concentration range from 0.30 to 60 µg kg?1. For both target analytes, the limit of detection (LOD) at signal-to-noise (S/N) ratio of 3 was 0.10 µg kg?1. In addition, a comparative study between the SWCNT and a commercial polydimethylsiloxane (PDMS) SPME fibre for the determination of bisphenol derivatives in canned food was conducted. SWCNT fibre showed higher extraction capacity, better thermal stability (over 350°C) and longer life span (over 150 times) than the commercial PDMS fibre. The method was successfully applied to determine BPA in canned food samples which were purchased from local markets. BPA was found in some of the samples within the concentration range from 0.5 to 5.2 µg kg?1.  相似文献   

17.
The occurrence of mycotoxins in 140 maize silages, 120 grass silages and 30 wheat silages produced in the Netherlands between 2002 and 2004 was determined using a liquid chromatography coupled with tandem mass spectrometry detection (LC-MS/MS) multi-method. Deoxynivalenol (DON) was detected above the limit of quantification (LOQ) of 250 μg kg?1 in 72% of maize and 10% of wheat silages. Average DON concentrations were 854 and 621 μg kg?1, respectively, and maximum concentrations 3142 and 1165 μg kg?1, respectively. Zearalenone was detected above the LOQ of 25 μg kg?1 in 49% of maize and 6% of grass silages. Average zearalenone concentrations were 174 and 93 μg kg?1, respectively, and maximum concentrations 943 and 308 μg kg?1, respectively. The incidences and average concentrations of DON and zearalenone in maize silage were highest in 2004. The incidence of other mycotoxins was low: fumonisin B1 and 15-acetyl-DON were detected in 1.4 and 5% of maize silages, respectively, and roquefortin C in 0.8% of grass silages. None of the silages contained aflatoxins, ochratoxin A, T2-toxin, HT2-toxin, sterigmatocystin, diacetoxyscirpenol, fusarenon-X, ergotamine, penicillinic acid, or mycophenolic acid. This study demonstrates that maize silage is an important source of DON and zearalenone in the diet of dairy cattle. Since the carryover of these mycotoxins into milk is negligible, their occurrence in feed is not considered to be of significant concern with respect to the safety of dairy products for consumers. Potential implications for animal health are discussed.  相似文献   

18.
Pork meat rejected by consumers because of a nauseating taint was analysed by gas chromatography and mass spectrometry (g.c.-m.s.) and found to contain 5–20 mg kg?1 of 1,4-dichlorobenzene. Trace amounts (10–35 μg kg?1) of 1,4-dichlorobenzene were found in wood-shavings used as litter materials and in the feedstuffs, but were considered insufficient to be the main cause of contamination. Meat from the following batch of pigs from the same source contained only very small amounts, similar to those present in normal pork obtained elsewhere (<25 μg kg?1). Examination of data recorded by g.c.-m.s. in the previous 2 years showed that 1,4-dichlorobenzene was present in trace quantity (>10μg kg?1) in several samples of normal meat, and appeared to be widespread in its occurrence.  相似文献   

19.
A sensitive flame atomic absorption spectrometry (FAAS) method was developed for the determination of cadmium (Cd) in brown rice and spinach. The method involves extraction with 1?M hydrochloric acid (HCl), followed by a selective pre-concentration by solid-phase extraction (SPE). The pH of the loading sample solution was adjusted to 4.0 for the brown rice and to 5.0 for the spinach. The masking agents, tartrate and citrate, were required for the spinach before pH adjustment. The SPE step achieved a 20-fold enrichment of the sample solution. The limits of quantification (LOQs) were 0.0054?mg?kg?1 for the brown rice and 0.0022?mg?kg?1 for the spinach, being more sensitive than those of AOAC Official method 999.10. A single-laboratory validation was performed by testing spiked samples at 0.04 and 0.08?mg?kg?1 for the brown rice, and 0.02 and 0.04?mg?kg?1 for the spinach. The average recoveries were 93.3–96.9% with relative standard deviations (RSDs) of 4.1–8.2% for brown rice, and 90.5–91.9% with RSDs of 5.8–10.0% for spinach.  相似文献   

20.
After simultaneous distillation–extraction (SDE) of foods packed in polystyrene (n = 77) and polypropylene cups (n = 42) from 61 different suppliers, coupled capillary gas chromatography–mass spectrometric (HRGC–MS) analyses indicated the presence of diastereomers of 2,2,4-trimethyl–1,3-pentanediol monoisobutyrate (TMPD-MIB; Texanol®), a known coalescent of paints and printing inks. The contaminant was found in 55 and 50% of the polystyrene and polypropylene packed samples, respectively. Amounts ranged 1.2–64.5 µg kg?1 in polystyrene cups (average 25.1 µg kg?1) and 0.9–45.7 µg kg?1 in polypropylene cups (average 10.8 µg kg?1). The origin of Texanol® in the printed plastic cups was demonstrated by separate HRGC–MS analysis, showing amounts in the higher µg kg?1 range. In addition, the presence of two pairs of enantiomers, both found to be racemic by enantioselective multi-dimensional gas chromatography–mass spectrometry (enantio-MDGC–MS), excluded it being of natural origin. The detection limit of overall procedure (DLOP) and the reliable quantification limit (RQL) were 0.2 and 0.9 µg kg?1, respectively. As the diester, 2,2,4-trimethyl–1,3-pentanediol diisobutyrate (TXIB), is on the EU list of regulated substances (restricted to single-use gloves only) with a migration limit of 5 mg kg?1 in food and is metabolised rapidly by hydrolysis, the observed migration of the monoester Texanol® at the µg kg?1 level poses no risk of adverse effects.  相似文献   

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