Rapid determination of benzo(a)pyrene in processed meat and fish samples by second-derivative constant-energy synchronous fluorescence spectrometry

A simple, rapid and cost-effective method has been established for the determination of the quantity of benzo(a)pyrene (BaP), one of the most carcinogenic polycyclic aromatic hydrocarbons (PAHs), in roasted, smoked and charcoal grilled foods. Second-derivative constant-energy synchronous fluorescence spectrometry (DCESFS) improves the spectral resolution and selectivity of the fluorescence method. By using this method, processed meat, fish and some other food samples were analysed without resorting to complex pre-separation and purification procedures. The method was found to have a recovery of 97.7%?±?4.3%. The limit of detection (LOD) for BaP was 0.14?µg?kg^–1, far below the regulatory limit (1.0?µg?kg^–1) for BaP in food samples specified by the European Union. A certified reference material (Coconut oil, BCR®-458) was used to confirm the validity of the proposed method. The results suggest that the measurements are in a good agreement with the certified BaP concentrations (5.4% deviation). The results obtained by the proposed method for analysing BaP in food samples correlated well with those obtained by GC/MS.     

Analysis of benzo[a]pyrene content from smoked food products in Korea

The content of benzo[a]pyrene (BaP) was evaluated from 100 smoked food products commonly consumed in Korean market with HPLC. Analysis method for BaP content on smoked food products was evaluated and validated. For validation, the efficiency of saponification time and solid phase extraction cartridges were evaluated. During 1–4 h of saponification, recovery of BaP was ranged from 90.17 to 98.87%. Among the 5 tested cartridges including florisil, silica gel, and alumina cartridges (acidic, basic, and neutral), the most efficient cartridge was florisil cartridge and the recovery of BaP was 98.87%. Limit of detection and limit of quantification was 0.03 and 0.09, respectively. As a result of BaP content analysis from smoked food products, the average BaP content was 0.45 μg/kg and the highest content of BaP was 2.87 μg/kg detected in smoked salmon product.     

Dowex Marathon A固相萃取-氢化物发生-原子荧光光谱法测定食品和水中硒含量

建立食品和水样中硒的Dowex Marathon A固相萃取-氢化物发生-原子荧光光谱检测方法,基于Dowex Marathon A树脂交换技术消除食品和水中金属离子对硒含量测定的干扰。硒的检出限为0.013μg/L,定量限为0.043μg/L,线性定量范围为0.1~10.0μg/L,线性相关系数为0.999 9,方法回收率不小于95%,相对标准偏差小于3%(n=11)。方法操作简单、灵敏度高、回收率好,适用于多种食品和水样中硒含量的测定,准确性通过标准物质验证,结果满意。     

高效液相色谱-荧光法测定油炸型膨化食品中4种多环芳烃

建立了高效液相色谱-荧光法(HPLC-FLD)测定油炸型膨化食品中苯并[a]蒽(BaA)、(CHR)、苯并[b]荧蒽(BbF)、苯并[a]芘(BaP)4种多环芳烃(PAHs)的分析方法。样品经饱和氯化钠分散后,采用正己烷萃取,经BAP-3分子印迹柱净化,Waters PAH C₁₈色谱柱分离,荧光检测器进行测定,外标法定量。在0.5~40 μg/L浓度范围内4种PAHs均有良好的线性(r>0.999),定量限为(LOQ)0.3~0.5 μg/kg。在空白样品中进行1、5、25 μg/kg 3个水平的加标回收实验,方法的平均回收率在90.3%~107.4%之间,精密度在6.5%以下。该方法简单、快速、灵敏、重现性好,可用于油炸型膨化食品中4种PAHs的定量测定。     

凝胶渗透色谱法测定食用植物油中苯并（a）芘

建立简便、准确的食用植物油中苯并（a）芘测定的凝胶渗透色谱-液相色谱荧光检测方法。样品经环己烷-乙酸乙酯（1∶1,v/v）溶解,利用凝胶渗透色谱系统净化,洗脱液经真空旋转蒸发浓缩后氮吹至干,乙腈定容后用带荧光检测器的高效液相色谱仪测定。结果,苯并（a）芘在0.21～52.50 ng/mL范围具有良好的线性,检出限为0.2 μg/kg,最低定量限为0.7 μg/kg,灵敏度高、线性好、范围宽。三级大豆油、四级菜籽油、一级菜籽油、一级山茶油、芝麻油、橄榄油共6 种不同种类和级别的食用植物油加标样品中低、中、高3 个添加水平的回收率在98.6%～103.5%之间,相对标准偏差（n=6）在2.98%～4.69%之间。2 a跟踪测定1 份芝麻油阳性样品10 次,其平均值为10.94 μg/kg,相对标准偏差为2.12%。建立的方法操作简单,能有效去除油脂基质的干扰,准确度高,重复性好,克服了GB/T 22509-2008《动植物油脂 苯并（a）芘的测定：反相高效液相色谱法》方法测定苯并（a）芘时氧化铝活度不易控制的技术难题,检测批量植物油样品中苯并（a）芘时效率提高。     

Determination of PAHs in various smoked meat products and different samples by enzyme immunoassay

An enzyme immunoassay was used to determine benzo[a ]pyrene (BaP) in smoked meat products and other samples of food and environmental origin. The method used has a detection limit (3 σ) of 0.1 μg kg⁻¹ and a coefficient of variation less than 10%. The main aim of the study was to compare the possible influence of different smoking processes and packaging material on the amount of BaP deposited on smoked meat product, mainly different sausages. The lowest amount of BaP was found when smoke produced by steam in the indirect method smoking‐chamber was used. A slightly protective effect of polyamide casing was noted. © 1999 Society of Chemical Industry     

同位素稀释电感耦合等离子体质谱法测定食品中的碘

采用同位素稀释法结合密封玻璃管的提取技术,建立了准确、灵敏的食品样品中碘的电感耦合等离子体质谱法（ID-ICP-MS）分析方法。样品中添加碲（128Te）同位素内标,以四甲基氢氧化铵（TMAH）为提取液,采用烧结玻璃试管密封,水浴振荡浸提样品中的碘,电感耦合等离子体质谱法测定,同位素稀释内标法定量。结果表明,碘在0.025 μg/L-50 μg/L范围内线性线性关系良好,相关系数为0.9999,线性方程为y=1.0506 x＋1.2511;当取样质量为0.1 g时,方法的检出限为1.8 μg/kg;在2.50、5.00和10.00 mg/kg 3个低、中、高添加水平,加标回收率在80.29%-104.70%之间,方法相对偏差小于5.0%;通过对海带标准物质GBW08517的测定,表明测定值与标准值之间无显著性差异。本方法简便、准确、灵敏度高,适用于多类食品中碘含量的测定。     

阿维菌素类农残检测方法的优化

为满足检测需求,提高效率,降低成本,建立阿维菌素类生物毒素在动物源性食品中残留的检测方法,并对不同基质样品的前处理进行优化讨论。利用乙腈作为提取液,在去除水分的条件下,三氟乙酸酐、N-甲基咪唑作为衍生化试剂,混合均匀后即完成前处理操作。利用高效液相色谱荧光检测器,C18色谱柱,在甲醇-水(92+8)条件下对被测物质进行准确定性定量分析,方法检出限达0.1μg/L,在0.1～20μg/L浓度水平进行基质加标,回收率在80%～108%,相对偏差为4.1%～11.4%。该方法操作简单、实用,灵敏度高,干扰小,满足检测实验室对动物源性食品中阿维菌素类生物毒素残留的检测需要。     

Study on ochratoxin A in cereal-derived products from Spain

A study on ochratoxin A (OTA) in cereal-derived products was carried out. Cereal-based baby foods, breakfast cereals and beers were analyzed for mycotoxin OTA using an in-house developed high-performance liquid-chromatographic method.OTA was detected in 19 of the 21 samples of breakfast cereals (limit of detection 0.066 μg/kg), in 14 of the 20 samples of cereal-based baby foods (limit of detection 0.035 μg/kg) and in 24 of the 31 samples of beer (limit of detection 0.012 μg/l). The mean concentrations of OTA found were the following: 0.265 μg/kg in breakfast cereals, 0.187 μg/kg in cereal-based baby food and 0.044 μg/l in beer. The influence of different factors, such as the fibre content in breakfast cereals, type of cereals used in cereal-based baby food and alcohol content in beer, on the OTA levels was studied.     

Determination of the level of benzo[a]pyrene in fatty foods and food supplements

A routine method was developed for the quantification of benzo[a]pyrene (BaP) in edible oils and food supplements. BaP is often taken as an indicator of the presence of polycyclic aromatic hydrocarbons. The method consists of on-line liquid chromatography clean-up followed by injection to an HPLC system with fluorescence detection. The method has good performance characteristics and gave good results in proficiency tests. From 2002 to 2004, about 1350 samples of oils and food supplements were analysed using this method to test the level of BaP. About 20% of the edible oils contained more than 1.2 µg kg^-1 BaP (which is the limit applied by the Dutch Food and Consumer Product Safety Authority until 1 April 2005, and includes measurement uncertainty). In the case of food supplements, more then 30% contained too high levels of BaP, ranging from 1.2 to 135 µg kg^-1.     

UPLC-MS/MS法同时测定不同动物源性食品中硝基呋喃代谢物残留

采用超高效液相色谱串联质谱法(UPLC-MS/MS),建立了猪肉、猪肝、螃蟹和虾4种不同动物源性食品中同时测定4种硝基呋喃类药物代谢物的检测方法,优化了样品前处理的条件以及UPLC-MS/MS仪器条件,样品经盐酸水解,2-硝基苯甲醛衍生,乙酸乙酯提取,ESI正离子模式扫描,多反应监测(MRM)测定。结果表明:采用本方法在4种动物源性样品基质中4种代谢物浓度在1~100 ng/mL范围内线性关系良好;4种代谢物的平均回收率为84.6%~118.1%;相对标准偏差RSD为2.9%~8.1%;在4种样品基质中,3-氨基-2-唑烷基酮(AOZ)的检出限为0.1 μg/kg,定量限为0.4 μg/kg,氨基脲(SEM)和5-甲基吗啉-3-氨基-2-唑烷基酮(AMOZ)的检出限为0.2 μg/kg,定量限为0.5 μg/kg,1-氨基乙内酰脲(AHD)的检出限为0.5 μg/kg,定量限为1.0 μg/kg,均满足国家标准要求。采用本方法对市场上随机购买的80份动物源性样品和鸡肉中硝基呋喃代谢物质控样进行检测,结果与国家标准方法GB/T 20752-2006测定结果相近,质控样的检测结果在量值范围内。该方法前处理操作简便,较传统方法节省时间和成本,可为硝基呋喃类药物残留检测技术提供理论支撑和参考。     

Occurrence and Safety Evaluation of Ochratoxin A in Cereal‐based Baby Foods Collected from Iranian Retail Market

Contamination of agricultural commodities with ochratoxin A (OTA) is a worldwide concern in recent decades. Consumption of OTA‐contaminated baby foods exerts health implications especially in children as the most vulnerable subpopulations. In the current study, for the first time in Iran, 64 baby foods (rice, wheat, and multigrain) samples from five different brands available in the Iranian market were analyzed to determine OTA level, using a HPLC with fluorescence detector. Overall, OTA was observed in 41% of analyzed samples with a mean and maximum level of 0.42 ± 0.27 and 1.1 μg/kg, respectively. OTA levels in five of 64 samples (7.8 %) were higher than the permissible limit recommended by European Commission (permissible limit: 0.5 μg/kg) and OTA levels in two of 64 samples (3.1%) were higher than the standard set by Iranian standard organization (1 μg/kg). The highest OTA contamination was observed in rice‐based baby food cereals (1.1 μg/kg; 57% of the samples), followed by wheat‐based (23%) and multigrain (20%) samples. OTA intake in infants (≥9 months old) was more than established provisional tolerable weekly intake by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) and the European Food Safety Authority (EFSA) (100 and 120 ng OTA per kg of body weight, respectively). OTA content in baby food and cereals, as well as other raw foodstuff should be investigated comprehensively to reduce the exposure rate of young children to OTA.     

Levels of benzo[a]pyrene and benzo[a]anthracene in smoked “Provola” cheese from Calabria (Italy)

Levels of benzo[a]pyrene (BaP) and benzo[a]anthracene (BaA) in “Provola” cheese samples from Calabria, smoked naturally and using commercial smoke-flavouring, have been determined. A comparative study of BaP and BaA concentrations was carried out on rind, exterior zone, core and slice of these samples. Quantitative determination of BaP and BaA was ascertained by HPLC using fluorescence detection. Levels of BaP and BaA were found in all smoked “Provola” cheese samples, but higher in cheese smoked with natural methods (0.46–1.13 µg kg^?1 for BaP and 1.38–9.29 µg kg^?1 for BaA) compared to samples smoked using commercial flavouring (0.085–0.32 µg kg^?1 for BaP and 1.20–2.98 µg kg^?1 for BaA). The smoking process contributes to polycyclic aromatic hydrocarbons contamination; however, for improved food safety, the use of commercial buffered smoke is preferable to traditional smoking procedures.     

Validation of an analytical method for the determination of cadmium (Cd) in fish by atomic absorption spectrometry with electrothermal atomisation

The validation of an analytical method was carried out for the determination of cadmium (Cd) in fish. The method was based on sample digestion in a microwave oven and subsequent reading using an atomic absorption spectrometer with a graphite furnace. The factorial design of experiments was applied to assess method ruggedness using the methodology of Box et al. [Box GEP, Hunter WG, Hunter JS. 1978. Statistics for experiments: an introduction to design, data analysis and model building. New York (NY): Wiley], studying the influence of sample mass, volume and concentration of acid used for sample digestion and the volume of modifier used. To study the possible matrix effect in the determination of Cd, the standard addition method was also performed. The results were treated using the OLS method. For the normality test a homoskedastic distribution was observed for the developed method and the results were adjusted to the statistical model proposed. F-tests and Student's t-tests indicated that there was no matrix effect on the calibration curve between the concentration range 1.0-10.0 μg Cd l(-1). Parameters such as selectivity, precision, decision limit, detection capability and limit of quantification were established by the method of standard addition to blank samples. The limit of quantification was 6.8 μg kg(-1). Accuracy, which was evaluated by using a certified reference material, was 107.0%. The recovery of the spiked analyte was 93.69% for the concentration of 50 μg kg(-1). Precision was defined by the coefficient of variation observed (Horrat value), estimated in terms of repeatability and reproducibility, and the values were below the limit, which is 2.0. The validation procedure confirmed the suitability of the method.     

Citrinin Determination in Red Fermented Rice Products by Optimized Extraction Method Coupled to Liquid Chromatography Tandem Mass Spectrometry (LC‐MS/MS)

A rapid and sensitive method was developed and validated for citrinin determination in red fermented rice products by liquid chromatography tandem mass spectrometry (LC‐MS/MS) under the selected reaction monitoring mode. Sample preparation was especially focused, and the quantitative methods of LC‐MS/MS and high‐performance liquid chromatography with fluorescence detection (HPLC‐FLD) were compared. In red fermented rice samples, the limit of detection was 1.0 μg/kg for LC‐MS/MS compared to 250 μg/kg for HPLC‐FLD, the limit of quantification was 3.0 μg/kg for LC‐MS/MS compared to 825 μg/kg for HPLC‐FLD. High correlation coefficient was obtained (R² = 0.999) within the linear range (0.1 to 100 μg/L) in the MS method. The recoveries ranging from 80.9% to 106.5% were obtained in different spiking concentrations. The average intra‐ and inter‐day accuracy ranged from 75.4% to 103.1%, and the intra‐ and inter‐day precisions were from 3.3% to 7.9%. The developed method was applied to 12 commercial red fermented rice products, and citrinin was found in 10 samples ranging from 0.14 to 44.24 mg/kg. Compared to traditional qualitative and quantitative methods, the newly developed LC‐MS/MS method for citrinin determination includes the merits of using a small amount of extraction solvent, simple preparation steps, and high sensitivity.     

Simultaneous determination of lincomycin and spectinomycin residues in animal tissues by gas chromatography-nitrogen phosphorus detection and gas chromatography-mass spectrometry with accelerated solvent extraction

A new multi-dimensional analytical method using gas chromatography-nitrogen phosphorus detection (GC-NPD) and gas chromatography-mass spectrometry (GC-MS) was developed for qualitative and quantitative measurement of lincomycin and spectinomycin residues in food animal tissues. This method is based on a new extraction procedure using accelerated solvent extraction (ASE). The analytes were extracted by phosphate buffer with trichloroacetic acid deproteinization and clean-up by C?? solid-phase extraction (SPE) adding dodecanesulfonic acid sodium salt as an ion-pair reagent. The eluted fraction was evaporated and derivatised with N,O-bis(trimethylsilyl) trifluoroacetamide (BSTFA) for GC-NPD analysis and GC-MS confirmation. Parameters for extraction pressure, temperature and cycle of ASE, clean-up, derivatisation and analysis procedure were optimised. The method was validated in muscle, kidney and liver of swine, bovine with a low concentration (limit of quantification) of 16.4 and 21.4 μg kg?1 for these two analytes using GC-NPD. For GC-MS, the limits of quantification were 4.1 and 5.6 μg kg?1, respectively. Spiked recoveries from levels of 20 to 200 μg kg?1 were found to be between 73% and 99% with a relative standard deviation (RSD) of less than 17% in GC-NPD. For GC-MS, levels from 5 to 20 μg kg?1 had between 70% and 93% with an RSD of less than 21%. This rapid and reliable method can be used for the characterisation and quantification of residues of lincomycin and spectinomycin in animal tissues.     

固相萃取结合高效液相色谱-串联质谱法测定鸡蛋中那西肽残留

建立鸡蛋样品中那西肽的高效液相色谱-串联质谱检测方法.样品经甲酸-乙腈溶液提取后,正己烷除脂,再经HLB固相萃取柱净化;样品溶液通过高效液相色谱-串联质谱进行检测,采用负离子模式电喷雾电离,配合多反应离子扫描分析目标化合物.分别对样品前处理条件及色谱质谱参数进行优化.结果表明,采用1％甲酸-乙腈溶液萃取,经HLB固相萃...     

Aflatoxin M1 in Parmesan Cheese: HPLC Determination

A method was developed to determine aflatoxin M, in Parmesan cheese produced in the Modena area during 1991. The analytical method was based on extraction of aflatoxin M, from the cheese by chloroform and clean-up by liquid-liquid extraction. The determination was made by high-pressure liquid chromatography. Of 200 fresh Parmesan cheese samples analyzed, 18 showed presence of aflatoxin M, in low concentrations (max. 0.190 μG/kg). Italian food law does not establish any maximum allowed level for this aflatoxin. The maximum limit proposed by the Swiss Federal Bureau of Health was 0.250 μg/kg.     

Untersuchungen zur Belastung von Futtermitteln,Obst und Gemüse mit Benzo(a)pyren (BaP) im Land Brandenburg

Investigation on the contamination of feeds, fruits and vegetables with benzo(a)pyren in the land Brandenburg Benzo(a)pyren (BaP) was analysed in 218 samples of grass, hay, straw, grains, lettuce, curly kale and apples by means of thin-layer chromatography und analysing other polycyclic aromatic hydrocarbons (PAH) by capillary gas chromatography and mass-spectrometry. Despite the fact that normally BaP concentrations were relatively low, up to 13.5 μg BaP per kg hay (dry matter) and 19.3 μg BaP per kg lettuce (dry matter) could be detected at some places.     

A slurry sampling method for the determination of iron and zinc in baby food by flame atomic absorption spectrometry

A slurry sampling method is proposed for the determination of iron and zinc in baby food by flame atomic absorption spectrometry without sample digestion prior to analysis. The effect of slurry concentration (the ratio of solid sample to total slurry volume), different acids at various concentrations as diluent and the addition of dispersant on accuracy and precision were investigated. The samples were dried at 105 °C overnight and ground using an agate mortar. To obtain quantitative recoveries, 500 mg of sample was slurried in 20 ml of 0.05% Triton X-114 containing 0.1 M HNO(3), homogenised using a high-performance overhead disperser at 15,000 rpm for 5 min and directly aspirated into the flame. The accuracy of the method was tested by determination of analytes in various certified reference materials. The limits of detection of the method (N = 10; 3σ) for iron and zinc were 5.5 and 3.4 μg g(-1), respectively, using a very dilute slurry of baby food, which gave a very low background signal. Finally, the proposed method was applied to the determination of iron and zinc in different baby food samples obtained from markets in Turkey. The range of iron and zinc content for the samples were 33-76 and 15-73 μg g(-1), respectively.