高效液相色谱法检测肉类食品中4种嘌呤碱

建立了肉类食品中嘌呤含量的多组分高效液相色谱分析方法。采用V(三氟乙酸)∶V(甲酸)∶V(水)=5∶5∶1溶液在90℃下水解样品12min,水解液浓缩后过膜,以0.02mol/LKH2PO4(pH=3.8)为流动相进行色谱分离;流速1.0mL/min;柱温30℃;DAD二极管矩阵检测器检测,检测波长254nm;进样量10μL。在0.4～40mg/L的浓度范围内,各嘌呤的响应峰面积与其相应浓度呈良好相关性,r>0.9999,通过水解条件实验证实,90℃下12min能够使样品中嘌呤完全水解为游离态,且不破坏嘌呤物质,相对标准偏差<16.0%。本方法分离度好,能够快速检测肉类食品中4种主要的嘌呤组分。     

支持向量回归-同步荧光光谱法预测鸭肉中克百威残留

为了满足鸭肉中克百威残留分析及快速检测的要求,基于克百威水解物在巯基乙醇存在的条件下能与邻苯二甲醛反应产生具有强荧光性衍生物的方法,建立了应用同步荧光光谱法测定鸭肉中克百威残留量的预测模型。对含有克百威鸭肉样品的三维同步荧光光谱进行分析,确定其最佳波长差Δλ为120 nm;利用遗传算法(GA)结合交互验证均方根误差(RMSECV)从240～450 nm光谱中筛选出19个波长作为定量分析模型的输入特征变量;对SVR、PCR、PLS 3种回归模型的性能进行比较,实验发现SVR模型的预测结果最好,其预测集的决定系数(r2)和预测均方根误差(RMSEP)分别为0.999 4和0.878 7。研究结果表明,采用同步荧光光谱法结合支持向量回归算法测定鸭肉中克百威的残留量,具有快速、预测精度高等特点,可为检测鸭肉中的克百威残留量提供一种可行的方法。     

填充条件对半制备柱性能影响的机理研究

对稀匀浆法填充半制备柱(Ф10 mm×100 mm)的过程进行研究,并用正交法对柱填充条件进行了优化,考察了压力、匀浆液组成、匀浆液体积对半制备柱填充效果的影响.由柱效和分离度定义式中的参数入手,讨论填充条件对柱性能的影响.通过计算总孔隙率ε_t、内部孔隙率ε_p、外部孔隙率ε_e、Van-Deemter曲线、吸附等温线等参数,发现填充压力对填充密度的作用最大,是最重要的影响因素;匀浆配比和匀浆体积共同影响其填充的均匀性.在压力11 MPa,流速275 mL/min,120 mL纯乙醇为匀浆液的条件下得到了最好的填充效果.     

Acrylamide concentrations in grilled foodstuffs of Turkish kitchen by high performance liquid chromatography-mass spectrometry

For over ten years, there has been a considerable interest in determination of acrylamide in foodstuffs. It was known that both protein-rich and carbohydrates-rich foods cooked at high-temperatures can cause acrylamide formation. However, carbohydrates-rich foods such as potato chips and biscuit samples have been the common studied foods compared with protein-rich foods such as meat samples.In this study, determination of acrylamide in these two group foods was examined using HPLC-MS. For this purpose, firstly, the parameters that are thought to affect the response in the HPLC-MS analysis were optimized. The optimized conditions were found to be 0.3 ml min^{− 1} for flow rate of mobile phase, 40 µl for injection volume, 5 °C for column temperature and 70 V for fragmentor potential. The optimized method was applied for the determination of acrylamide levels in Turkish foodstuffs including grilled meat and chicken samples, potato chips, coffee and biscuit. The obtained concentrations for all studied foods were in the range of 20–250 µg kg^{− 1}. The results showed that acrylamide concentrations highly varied depending on the kind of food samples.     

Validation of a liquid chromatography–tandem mass spectrometry method for the identification and quantification of 5-nitroimidazole drugs and their corresponding hydroxy metabolites in lyophilised pork meat

A liquid chromatography–electrospray ionisation tandem mass spectrometry method for the simultaneous detection and quantitation of 5-nitroimidazole veterinary drugs in lyophilised pork meat, the chosen format of a candidate certified reference material, has been developed and validated. Six analytes have been included in the scope of validation, i.e. dimetridazole (DMZ), metronidazole (MNZ), ronidazole (RNZ), hydroxymetronidazole (MNZOH), hydroxyipronidazole (IPZOH), and 2-hydroxymethyl-1-methyl-5-nitroimidazole (HMMNI). The analytes were extracted from the sample with ethyl acetate, chromatographically separated on a C₁₈ column, and finally identified and quantified by tandem mass spectrometry in the multiple reaction monitoring mode (MRM) using matrix-matched calibration and ²H₃-labelled analogues of the analytes (except for MNZOH, where [²H₃]MNZ was used). The method was validated in accordance with Commission Decision 2002/657/EC, by determining selectivity, linearity, matrix effect, apparent recovery, repeatability and intermediate precision, decision limits and detection capabilities, robustness of sample preparation method, and stability of extracts. Recovery at 1 μg/kg level was at 100% (estimates in the range of 101–107%) for all analytes, repeatabilities and intermediate precisions at this level were in the range of 4–12% and 2–9%, respectively. Linearity of calibration curves in the working range 0.5–10 μg/kg was confirmed, with r values typically >0.99. Decision limits (CCα) and detection capabilities (CCβ) according to ISO 11843-2 (calibration curve approach) were 0.29–0.44 and 0.36–0.54 μg/kg, respectively. The method reliably identifies and quantifies the selected nitroimidazoles in the reconstituted pork meat in the low and sub-μg/kg range and will be applied in an interlaboratory comparison for determining the mass fraction of the selected nitroimidazoles in the candidate reference material currently developed at IRMM.     

辐照肉制品中2-十二烷基环丁酮的测定

采用GB/T 21926-2008《辐照含脂食品中2-十二烷基环丁酮测定气相色谱/质谱法》对辐照肉制品中的2-十二烷基环丁酮进行测定,鉴别辐照肉制品。样品用索氏抽提,经冷冻离心和弗罗里硅土层析净化,用气相色谱质谱联用法测定。2-十二烷基环丁酮的浓度在0.01~0.5 mg/L与色谱峰面积呈良好的线性关系,r=0.999 6。对未经辐照的样品进行加标回收试验,加标回收率为83.1%~94.0%,测定结果的相对标准偏差小于6%(n=6)。     

畜禽肉及饲料中氟苯尼考残留免疫分析方法研究

针对动物源性食品及饲料中氟苯尼考的残留问题,通过抗原制备、动物免疫和细胞融合筛选,成功得到可高特异性识别氟苯尼考的单克隆抗体,并建立了氟苯尼考的间接竞争酶联免疫分析(icELISA)方法.经单因素实验优化策略,确定最佳反应条件为:包被抗原质量浓度0.05μg/mL,抗体质量浓度为0.1μg/mL,最佳药物、抗体和二抗稀...     

Aronia melanocarpa (Michx.) Elliot,Chaenomeles superba Lindl. and Cornus mas L. Leaf Extracts as Natural Preservatives for Pork Meat Products

The aim of this study was to investigate the possibility of using Aronia melanocarpa, Chaenomeles superba, and Cornus mas leaf extracts as natural preservatives for pork meat products. Pork sausages were stored in modified atmosphere packaging (MAP) (80% N₂ and 20% CO₂) at 4 °C for 29 days. The total psychrotrophic counts (TPC) were determined during the storage period, along with the numbers of Enterobacteriaceae and lactic acid bacteria (LAB). The extracts improved the microbial quality of the meat products but to a lesser extent than sodium nitrate (III). They reduced the amounts of Enterobacteriaceae and LAB. The A. melanocarpa leaf extract showed the strongest preservative effect. The bacterial biodiversity of the meat products was investigated based on high-throughput sequencing of the 16S rRNA gene. Two predominant bacteria phyla were identified, Proteobacteria and Firmucutes, mostly consisting of genera Photobacterium, Brochothrix, and Carnobacterium. The extracts also influenced microbial community in sausages decreasing or increasing bacterial relative abundance. The extracts significantly inhibited lipid oxidation and improved the water-holding capacity of the meat, with C. superba extract showing the strongest influence. In addition, A. melanocarpa and C. superba improved the redness (a*) of the sausages. The results of this study show that A. melanocarpa, C. superba, and C. mas leaf extracts can extend the shelf life of meat products stored in MAP at 4 °C.     

Radiation decontamination of meat lyophylized products

There is an increasing demand for a powder soups and sauces composed with lyophylizated meat. Technology of lyophylization is not always accompanied by thermal treatment of raw materials. That is the reason the meat lyophylization process does not ensure as good microbiological quality as is required. Degree of microbiological decontamination and organoleptic properties of lyophilized meat were investigated after radiation treatment.     

Simultaneous determination of multiveterinary drug residues in pork meat by liquid chromatography‐tandem mass spectrometry combined with solid phase extraction

An LC‐MS/MS method developed for simultaneous analysis of 54 veterinary drug residues of six families in pork meat samples, including sulfanilamide, nitroimidazoles, quinolones, macrolide antibiotics, lincosamides, and praziquantel. The pork meat sample was prepared by extraction with ACN, and clean‐up on a C₁₈ SPE cartridge. The sample was separated on a C₈ column and eluted with ACN, methanol, and formic acid. The MS/MS detector is operated in the multiple reaction monitoring mode, acquiring two specific precursor‐product ion transitions per target compound. The method showed excellent linearity (R² ≥ 0.99) and high precision (relative SD, RSD ≤ 19.8%) for all compounds. The method quantification limits of 54 veterinary drug residues were in the range of 0.3–3.0 μg/kg. Recoveries for most analytes based on matrix‐matched calibration in matrices were 20.9–121.0%. This method has been successfully applied for analysis of more than 100 pork meat samples from the local market; five of the 54 drugs were detected.