高效液相色谱法快速测定猪肉中醋酸地塞米松残留物

本文研究了一种快速、简便测定猪肉中醋酸地塞米松残留的高效液相色谱法。肉样用二氯甲烷提取，甲醇溶解残留物，２４０ｎｍ处紫外检测。在０．０６￣１．５０μｇ／ｋｇ浓度范围内，醋酸地塞米松线性相关系数为０．９９９２，相对标准偏差分别为２．９２％（日内）和４．７８％（日间）。空白肉样添加０．０５￣０．２０ｍｇ／ｋｇ醋酸地塞米松，其回收率在７５．６０％￣８７．９０％。本法可检测出样品中低至５０μｇ／ｋｇ的醋酸     

The Analysis of Sulphonamide Drug Residues in Pork Muscle using Automated Dialysis

ABSTRACT

The aim of this study was to assess the suitability of automated dialysis, using a commercial system, for the analysis of sulphonamides in porcine tissue. The system involves automated dialysis, followed by trace enrichment of the dialysate prior to HPLC determination. The procedure was applied to the analysis of nine sulphonamide drug residues using reversed phase HPLC as the method of determination. Muscle samples were blended in saline, centrifuged and the supernatant was filtered before dialysis for an optimised time of 11 min. The resulting dialysate was concentrated on a reversed phase trace enrichment cartridge prior to HPLC analysis with UV detection at 280 nm. The developed method was evaluated by carrying out intra- and inter-assays on fortified porcine muscle. Mean recoveries, evaluated from the inter-assay study, were 80% or higher for the nine sulphonamides studied and the limit of determination for the method was 40 ng g^?1.     

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.     

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.     

高效液相色谱法测定猪肉脯中胭脂虫红的含量

提出了高效液相色谱法测定猪肉脯中胭脂虫红含量的方法。试样用2mol·L-1盐酸溶液提取,加入甲醇,离心分离,取上清液经SPE柱净化后,以C18色谱柱为固定相,以乙腈与0.5%(体积分数)磷酸溶液以体积比80比20组成的混合液为流动相进行色谱分离,在检测波长275nm处进行测定。胭脂虫红的质量浓度在0.5~50mg·L-1范围内与其峰面积呈线性关系,方法的检出限(3S/N)为0.15mg·kg-1。以猪肉脯样品为基体进行加标回收试验,所得回收率在89.0%~97.8%之间,相对标准偏差(n=6)在2.4%~3.9%之间。     

光学扩散特征的生鲜肉细菌总数的无损检测方法

细菌总数是生鲜肉的最主要安全参数之一,肉品的光学扩散特征反映其细菌总数。对高光谱扩散数据利用不同的拟合算法处理与分析,并比对生鲜猪肉细菌总数建模的相关性差异,确定了用于最终建模的最佳扩散特征参数,为后续的装置开发提供建模依据。冰箱调至4℃恒温,在里面放置63个分割好的猪肉样品,每天间隔固定时间从里面随机取出4~5块样品,获取猪肉表面的400~1 100nm波长范围内高光谱散射图像,从高光谱图像中提取猪肉的扩散光谱曲线,利用Lorentz函数和Gompertz函数以及修正后的函数,拟合处理与分析扩散数据,拟合后的不同参数可以代表样品的特征光谱,细菌总数的标准值用平板计数法获得,然后单独用各单个参数、多个参数结合的方式,多元线性回归的统计方法,与细菌总数分别建立模型。实验结果表明,Lorentz三参数结合,Lorentz四参数结合,Gompertz四参数拟合的模型相关系数较高,其校正集和预测集相关系数分别为0.93,0.96,0.96和0.90,0.90,0.92,标准偏差分别为0.47,0.44,0.39和0.56,0.46,0.42,其中,相关性最好的是Gompertz四参数结合,在装置的开发中可以优选相关性和稳定性最好的模型导入装置系统中。     

基于LIBS技术结合PCA-SVM机器学习对猪肉部位的识别研究

近年来,激光诱导击穿光谱（LIBS）与算法相结合分类、识别生物组织逐渐兴起。由于猪肉各部位组织光谱特性相似,仅通过分析光谱信息很难达到准确识别的效果,采用来自于同一个体、四个不同部位的猪肉进行研究,并将其进行切片、压平,应用LIBS技术对4种部位的组织（里脊,梅花,前腿,五花）进行了样品光谱的采集,每种样品采集100幅光谱进行分析,选取Ca,Na,K等6条谱线进行了初步光谱分析,观测谱线发现除脂肪含量较多的五花组织C-N以及C含量较其他组织高以外,其他组织很难区分,进一步对这6个成分进行主成分分析（PCA）,得到PC1,PC2,PC3累计贡献率达到95%,通过特征分数作为支持向量机（SVM）模型输入源,建立SVM分类模型,得到几种部位样品的混淆矩阵图,通过观察混淆矩阵可以清楚分辨出每个种类样品的分类整准确率,发现四种样品准确率分别为96%,98%,97%,100%,平均准确率达到了97%以上。研究证明LIBS结合PCA-SVM可作为一种快速鉴别猪肉不同组织部位的检测方法。     

基于近红外光谱检测猪肉系水力的研究

为了快速无损无污染得测定猪眼肌的系水力,提出了用近红外漫反射光谱检测真空包装猪肉的系水力的新方法.采用常规的滴水损失法和压力法标定猪肉的系水力.利用光谱专用分析软件Unscramb-ler9.6,对采集的光谱进行平滑,二阶微分预处理,用偏最小二乘法(PIS)建立其定量检测模型.该实验的样本总数为106,将样品分为校正集和检验集.用校正集建立定标方程,用检验集检验定标方程的预测精度.常规方法与近红外光谱漫反射法的预测植的相火系数为0.73～0.79,结果明显要好于近红外透射法和反射光谱法.该研究验证了近红外光谱漫反射法对真空包装后鲜猪肉的系水力的无损检测的可行性.     

高效液相色谱-质谱联用法检测猪肉中5种青霉素的残留量

建立了高效液相色谱与质谱联用法测定猪肉中5种青霉素类药物残留的方法.样品采用体积分数0.5%的乙酸提取,匀浆离心分离后通过XAD-2固相萃取柱净化,甲醇洗脱后,用质谱检测器检测.采用Agilent HC-C18色谱柱(250 mm×4.6 mm i.d.,5 μm),以体积分数0.1%NH3·H2O和乙腈为流动相进行梯度洗脱.在添加水平为0.1、0.2、0.5 mg/kg时,回收率在52%～82.8%之间,相对标准偏差在3.4%～9.2%之间,对于不同的药物,方法的检出限为0.001～0.005 mg/kg.该方法适合于猪肉组织中青霉素类药物残留量的检测.     

Effects of dielectric barrier discharge plasma on pathogen inactivation and the physicochemical and sensory characteristics of pork loin

This study aimed to evaluate the use of a dielectric barrier discharge (DBD) plasma system to improve the safety of pork loins. When pork loin was exposed to DBD plasma with the input gases He and He + O₂, the population of Escherichia coli was reduced by 0.26 and 0.50 log cycles following a 5-min treatment and by 0.34 and 0.55 log units following a 10-min treatment, respectively. That of Listeria monocytogenes was also reduced from 0.17 to 0.35 and 0.43 to 0.59 log cycles when the samples were exposed to DBD for 5 and 10 min using He and He + O₂, respectively. The pH and L*-values (lightness) of the samples decreased significantly with DBD plasma treatment, but a*- (redness) and b*-values (yellowness) exhibited no obvious changes. Lipid oxidation, measured by TBARS values, was greater in samples with He + O₂ than in other samples. Significant reductions in sensory quality parameters (appearance, color, odor, acceptability, etc.) were observed in DBD-treated samples. These results indicate that the DBD plasma system has potential for use in sanitizing pork loins by inactivation of foodborne pathogens, although the effect was limited. In order to meet market requirements, however, a method to overcome sensory deterioration of pork loins should be developed and applied.