mSPE前处理-超高效液相色谱串联质谱法测定牛奶中阿维菌素类药物残留

本文建立了采用磁性固相净化材料（mSPE）对牛奶样品进行净化,使用超高效液相色谱-串联质谱（UPLC-MS/MS）对牛奶中阿维菌素类药物残留进行定性和定量的检测方法。牛奶样品使用乙酸锌和亚铁氰化钾沉淀蛋白,8 mL乙腈提取,10 mg磁性HLB净化材料净化,5%乙腈-水、乙腈进行淋洗和洗脱,使用UPLC-MS/MS检测牛奶中阿维菌素、乙酰氨基阿维菌素、伊维菌素和多拉菌素四种药物。在0.2～200.0 μg/L药物浓度范围内线性关系良好(R2 > 0.995)。该方法阿维菌素、伊维菌素和多拉菌素的检测限为0.2 μg/kg,定量限为0.5 μg/kg;乙酰氨基阿维菌素的检测限为0.5 μg/kg,定量限为2.5 μg/kg,回收率为82.3%～ 88.2%,相对标准偏差（RSD）为0.23%～4.19%。本文建立的mSPE前处理技术,同现行国标GB 31659.4-2022相比,极大的提高了样品前处理效率,缩短了样品检测的时间,降低了检测成本,减少了有机溶剂的使用。所建立的方法检出限和定量限均可满足食品安全国家标准GB 31650-2019中规定的牛奶中阿维菌素类药物残留限量的要求,可应用于定量检测牛奶样品中阿维菌素类药物残留,为mSPE前处理方法的广泛应用提供宝贵经验。     

液相色谱法自制净化柱测定饲料中5种黄曲霉毒素

通过用自制净化柱净化,利用高效液相色谱仪对饲料中的黄曲霉毒素B1、B2、G1、G2、M1同时进行检测,样品经体积分数为84%的乙腈溶液提取,提取液通过自制净化柱净化、浓缩,三氟乙酸(TFA)柱前衍生,C18色谱柱分离,荧光检测器检测,外标法定量。5种黄曲霉毒素经过衍生后线性良好,对添加黄曲霉饲料样品进行加标回收,回收率在85%~102%,效果良好。     

高效液相色谱光化学在线衍生荧光法检测鸡肉中16 种磺胺类药物残留

采用高效液相色谱-光化学柱后在线衍生-荧光检测法检测鸡肉中16 种磺胺类药物残留量。鸡肉样品经过乙腈提取并脱脂净化,色谱柱分离,光化学在线衍生并直接用荧光检测器检测。流动相为0.3%的冰乙酸和甲醇溶液梯度洗脱,流速0.7 mL/min、柱温36 ℃,激发波长320 nm、发射波长450 nm,16 种磺胺类药物得到良好分离。16 种磺胺药物在0.13～67.89 μg/mL质量度范围内,线性良好（R≥0.994 0）,回收率在61.2%～106.6%之间,相对标准偏差为0.3%～13.9%,检出限为1.0～67.4 μg/kg。该方法灵敏、准确、快速,可满足鸡肉中磺胺类残留的检测。     

高压液相色谱-荧光法检测辣椒干中阿维菌素残留量

目的 建立辣椒干中阿维菌素残留量的高压液相色谱-荧光检测器分析方法。方法 样品采用乙腈提取, 乙腈饱和的正己烷去脂, 石墨化碳固相萃取小柱净化, 以三氟乙酸酐(trifluoroacetic anhtdride, TFAA)和N-甲基咪唑(1-methylimidazole, NMIM)的乙腈溶液衍生化, 用C18柱分离, 在激发波长为365 nm, 发射波长470 nm的条件下高压液相色谱-荧光法检测。结果 方法在10~500 ng/mL的浓度范围内线性关系良好, 相关系数为r=0.999, 检测限为5 μg/kg。3个不同浓度水平上进行了加标回收率在90.3%~103.1%, RSD在2.31%~6.93%。结论 该方法简便灵敏, 准确快速, 可用于辣椒干中阿维菌素残留量的测定。     

POD-UPLC检测固体运动营养品中γ-氨基丁酸的含量

建立一种柱前在线衍生-超高效液相色谱法检测固体运动营养品中γ-氨基丁酸(GABA)的方法。样品由2%三氯乙酸溶液按料液比1:5 (g/mL)超声提取30 min,上清液经邻苯二甲醛在线衍生后,以80%乙腈-水(含20 mmol/L乙酸钠溶液,pH2.7)为流动相,检测波长为207.6 nm,外标法峰面积定量。结果表明,GABA在1.0～100.0 μg/mL浓度范围内线性良好,检出限为0.1 mg/kg,定量限为0.5 mg/kg,加标回收率达到96.5%～102.6%。该方法具有操作简单、专属性强、灵敏度高等优点,可满足固体运动营养品中GABA的检测要求。     

小麦粉中偶氮甲酰胺检测技术研究

本文建立了小麦粉中偶氮甲酰胺的高效液相色谱检测方法。样品经乙腈振荡提取,过LC-C18柱净化,以乙酸铵-乙腈溶液(90:10)为流动相,氨基柱分离,DAD检测器检测。该方法线性范围为5.00～50.0μg/mL,变异系数为3.0%,平均加标回收率80%～92%。该方法准确可靠,精密度、重现性较好。     

高效液相色谱-光化学柱后衍生法测定紫苏籽中黄曲霉毒素B1

目的建立一种高效液相色谱-光化学柱后衍生法测定紫苏籽中黄曲霉毒素B_1的检测方法。方法样品经乙腈-水溶液(84:16,V:V)提取,用免疫亲和柱净化后,经光化学衍生器衍生,在高效液相色谱仪荧光检测器上检测。结果该方法对黄曲霉毒素B_1的最低检测限为0.05μg/kg,定量限为0.20μg/kg,相关系数为0.9990,加标回收率为86.0%～93.5%,相对标准偏差(relative standard deviation, RSD)为1.94%。结论该方法快速、准确、灵敏,适合测定紫苏籽中黄曲霉毒素B_1的含量。     

免疫亲和柱-高效液相色谱法同时检测谷物中T-2毒素和HT-2毒素含量

建立了免疫亲和柱净化-柱前化学衍生-高效液相色谱荧光检测器同时检测谷物中T-2毒素和HT-2毒素的方法。样品经溶剂[V(甲醇)∶V(水)=80∶20]提取,通过免疫亲和柱净化(IAC),以氰酸蒽(1-AN)为衍生化试剂、4-二甲基氨基吡啶(DMAP)为催化剂进行衍生,以ZORBAX Eclipse XDB苯基柱为分离柱,乙腈-水为流动相进行高效液相色谱分离和检测。在0.005⁰.5μg/g内呈良好线性,检出限为0.005μg/g,添加回收率为82.0%0.5μg/g内呈良好线性,检出限为0.005μg/g,添加回收率为82.0%¹08.0%,RSD<15.5%。     

HPLC-柱后光化学衍生法检测花生酱中黄曲霉毒素

建立高效液相色谱-在线柱后光化学衍生-荧光检测器检测花生酱中黄曲霉毒素B1、B2、G1、G2的含量。样品以乙腈-水(80∶20)溶液提取,经免疫亲和柱净化后,利用在线柱后光化学衍生-HPLC-FLD进行分析测定。结果:在优化条件下,黄曲霉毒素B1、G1在0.30 mg/L~10 mg/L,黄曲霉毒素B2、G2在0.06 mg/L~3.0mg/L线性关系良好,r0.998,回收率80%~101%,RSD5.9%。黄曲霉毒素B1、B2、G1、G2的检测限(LOD)分别为0.10、0.03、0.15、0.04μg/kg。     

柱后衍生法检测鳗鱼肌肉中磺胺类药物残留量研究

建立了鳗鱼肌肉中磺胺类药物残留的高效液相色谱柱后衍生分析方法。鳗鱼肌肉样品经乙腈和水提取,液- 液分配和固相萃取净化浓缩后,采用高效液相色谱柱后衍生法检测磺胺类药物经C18 色谱柱分离,在柱后反应单元中与荧光胺反应,生成具有荧光特性的分子,荧光检测器检测方法定量检测限为2.0μg/kg,磺胺浓度在0.005～0.2μg/ml 范围内线性关系良好(r ≥ 0.9998),磺胺浓度范围在2.0～50.0μg/kg 鳗鱼肌肉加标样,日内和日间回收率为85.1%～90.2%,相对标准偏差2.74%～6.04%。实验结果表明,该检测方法适用于低浓度水平鳗鱼肌肉中磺胺类药物残留检测。     

Impact of Some Avermectins on Lactoperoxidase in Bovine Milk

Many macrocyclic lactones, including avermectins, are known to be used as a veterinary drug, agricultural pesticides, and insecticides. Lactoperoxidase (EC 1.11.1.7) is one of the peroxidases found in milk. Lactoperoxidase has a natural host defense system against micro-organisms and a natural antimicrobial system. In this study, some macrocyclic lactones, including emamectin-benzoate, doramectin, eprinomectin, abamectin, moxidectin-vetranal, and ivermectin were investigated for in vitro inhibitory effects on the bovine lactoperoxidase enzyme, which was purified using amberlite CG-50 H⁺ resin and sepharose 4B-L-tyrosine-sulphanamide affinity chromatography 344.6-fold, with a yield of 61.1% and a specific activity of 39.11 EU/mg protein. Emamectin-benzoate, doramectin, eprinomectin, abamectin, moxidectin-vetranal, and ivermectin are also known strong antiparasitary properties. In this study, we demonstrated that avermectins have strong lactoperoxidase inhibitory effects. Of these, the emamectin-benzoate was shown to have the most inhibiting effect against lactoperoxidase with Ki value of 6.82 ± 2.60 µM.     

Fate of eprinomectin in goat milk and cheeses with different ripening times following pour-on administration

The distribution of eprinomectin in goat milk and cheeses (cacioricotta, caciotta, caprilisco) with different ripening times following a pour-on administration at a single dose rate (500 microg/kg of body weight) and a double dose rate (1,000 microg/kg of body weight) to goats with naturally occurring infections of gastrointestinal nematodes was studied. Milk residues of eprinomectin reached a maximum of 0.55+/-0.18 microg/kg and 1.70+/-0.31 microg/kg at the single and double doses, respectively. The drug concentrations decreased progressively until the fifth day after treatment, when they were less than the detection limit at both dose rates. The eprinomectin levels measured in all cheese types (both treatments) were higher than those recovered in milk at all the sampling times. In caciotta cheeses, the eprinomectin residues levels were constantly higher than other cheeses. With the exception of cheeses made with milk the first day after treatment, eprinomectin concentrations were nearly constant up to the fourth day then decreased by the fifth and sixth days after treatment. In all cases, at both the single and double dosages, the maximum level of eprinomectin residues in goat milk and cheeses remained below the maximum residual level of 20 microg/liter permitted for lactating cattle.     

竞争ELISA 法对牛乳β - 酪蛋白的检测

通过确定包被抗体最佳稀释度(anti- β-CN IgY 1:160)、封闭液及封闭时间(含1% 明胶的PBST,封闭1h)、酶标抗原(1:20)和待测脱脂牛乳样品稀释液(1:80)抗体作用时间(60min)、底物最佳反应时间(20min)、温度(37℃)等对竞争ELISA 效果有重要影响的因素,建立检测牛乳β- 酪蛋白的竞争ELISA 法。经敏感性实验和重复性实验证明本实验建立的竞争ELISA 法最低检出量为5.1μg/mL,变异系数(CV)小于5%,可以开发应用于牛乳及其制品的蛋白质品质快速检测。     

Detection of bovine milk adulteration in caprine milk with N-acetyl carbohydrate biomarkers by using 1H nuclear magnetic resonance spectroscopy

In a return to tradition, the popularity of caprine milk is on the rise. However, particularly in countries with developed dairy industries based on bovine milk, there is the risk of adulteration with bovine milk, which is a cheaper alternative. Thus, a rapid, robust, and simple method for the detection of bovine milk added to caprine milk is necessary, and ¹H nuclear magnetic resonance spectroscopy appears to provide a solution. A matrix of 115 pure and artificially adulterated pasteurized milk samples was prepared and used to discover biomarkers of bovine milk that are independent of chemical and biological variation caused by factors such as genetics, diet, or seasonality. Principal component analysis and orthogonal projections to latent structures discriminant analysis of pure bovine milk and pure caprine milk revealed spectral features that were assigned to the resonances of 4 molecules. Of these, the peaks corresponding to protons in the N-acetylglucosamine and N-acetylgalactosamine acetyl moieties showed significant applicability for our method. Receiver operating characteristic curve analysis was used to evaluate the performance of the peak integrals as biomarkers of adulteration. This approach was able to distinguish caprine milk adulterated with 5% of bovine milk with 84.78% accuracy and with 10% of bovine milk an excellent 95.65% accuracy. This study demonstrates that N-acetyl carbohydrates could be used as biomarkers for the detection of bovine milk in caprine milk and could help in protecting caprine milk authenticity.     

免疫亲和柱结合超高效液相色谱-串联质谱法测定牛奶中的16种真菌毒素比较研究

目的 通过比较5种不同商品化多合一免疫亲和柱的可检测目标毒素种类、回收率和稳定性,筛选性能最优的免疫亲和柱,建立免疫亲和前处理-超高效液相色谱-串联质谱法(ultraperformanceliquid chromatography-tandem mass spectrometry, UPLC-MS/MS)测定牛奶中16种真菌毒的方法。方法 牛奶样品分别经5种不同多毒素免疫亲和柱进行净化富集,用优化后的UPLC-MS/MS,在多反应监测模式下测定,同位素内标法定量,筛选覆盖牛奶中真菌毒素污染种类全面、回收率和稳定性最佳的免疫亲和柱,并进行免疫亲和柱性能评价和方法学验证,最终将方法应用于实际样品检测。结果 免疫亲和柱A对牛奶中16种真菌毒素在低、中、高3个添加水平均具有良好的准确度和精密度,加标回收率在83.6%～126.8%之间,相对标准偏差为0.2%～18.4%。柱A内各毒素残留水平低于仪器检出限,柱容量在21.8～1317.5 ng之间。使用免疫亲和柱A富集净化样品,各目标毒素在线性范围内线性良好,相关系数均大于0.99,定量限为0.0010～0.2000ng/g。应用该方法对牛奶质...     

QuEChERS结合超高效液相色谱-串联质谱法测定牛奶中莫昔克丁残留

目的建立超高效液相色谱-串联质谱法(ultra performance liquid chromatography-tandem mass spectrometry,UPLC-MS/MS)检测莫昔克丁在牛奶中残留的分析方法。方法采用1%乙酸乙腈振荡提取,离心后取上清液加乙二胺-N-丙基硅烷吸附剂[N-(n-Propyl)ethylenediamine,PSA]和十八烷基键合硅胶(C18)混合净化,上清液氮气吹干后用50%乙腈水溶液定容后供LC-MS/MS测定。结果在0.0005~0.20 mg/L浓度范围内线性良好,相关系数为0.9993。莫昔克丁在牛奶中的添加水平为0.002~0.20mg/kg,平均回收率为75.0%~82.6%,相对标准偏差为3.6%~4.8%。结论本方法快速、灵敏度高,适用于牛奶中莫昔克丁的检测。     

PCR detection of bovine mitochondrial DNA derived from meat and bone meal in feed

Because bovine meat and bone meal (MBM) is thought to be a major source of bovine spongiform encephalopathy, we developed a PCR-based method for detection of bovine MBM in animal feed. We isolated bone particles from feed containing bovine MBM using a separation technique based on specific gravity and then washed bone particles with sodium hypochlorite solution and an EDTA-proteinase K solution. The mitochondrial DNA was extracted from bone particles and amplified using PCR with cattle-specific primers. Bovine DNA was not detected in a milk replacer containing dried skim milk and dried whey, but bovine DNA was detected in the milk replacer that was mixed with bovine MBM. Other cattle-derived materials in feeds did not interfere with the selective detection of bovine MBM. This method allowed detection of bovine mitochondrial DNA in feed with 0.1% added bovine MBM. When the treatment with sodium hypochlorite was excluded, bovine DNA derived from MBM could not be distinguished from bovine DNA derived from other bovine materials. However, the exclusion of this treatment improved the detection limit of bovine MBM in feed. This method appears suitable for the selective detection of bovine MBM in feed.     

Determination of sulbactam in raw bovine milk by isotope dilution–ultra-high-performance liquid chromatography–tandem mass spectrometry

We developed a sensitive and selective isotope dilution ultra-high-performance liquid chromatography–tandem mass spectrometry (UPLC-MS/MS) method for the determination of sulbactam residue in raw bovine milk. Sulbactam and internal standard, sulbactam-d₅, were extracted from raw bovine milk via liquid-liquid extraction and enriched with strong anion exchange solid-phase extraction cartridges and finally analyzed by using UPLC-MS/MS with multiple reaction monitoring mode. The method was validated according to European regulations. The calibration curve showed good linearity, with a correlation coefficient of 0.9998. Decision limit and detection capability of sulbactam were determined by matrix calibration curve and were 0.0445 and 0.0517 μg/L, respectively. The recoveries of sulbactam in fortified raw bovine milk ranged from 72.1 to 91.5%, with the intra- and interday relative standard deviations ranging from 3.0 to 18.9%. Furthermore, the developed method was applied to analyzing real raw bovine milk samples collected from dairy farms in Beijing, China. Sulbactam was not determined in all samples. The proposed method could ultimately serve as a methodological foundation for the determination of sulbactam in different types of raw milk and dairy products.     

Automated determination of oxytetracycline residues in muscle, liver, milk and egg by on-line dialysis and post-column reaction detection HPLC.

An automated method for control of oxytetracycline (OTC) residues in chicken and bovine muscle, salmon liver, bovine milk and hen egg has been developed. Tissue homogenate, decreamed milk or whole egg solution was dialysed and the dialysate enriched on a small polystyrene column on-line to HPLC. OTC and the internal standard (tetracycline) were separated on a polystyrene column by ion-pair chromatography. The column effluent was mixed with sodium hydroxide and irradiated at 366 nm. Monitoring the resulting derivatives with a fluorescence detector (excitation: 358 nm, emission: 460 nm), OTC could be detected at 1 ng/ml in milk, 1 ng/g in egg, 3-4 ng/g in muscle and 8 ng/g in liver. Relative standard deviations at 50 and 200 ng/g (milk: 20 and 100 ng/ml) ranged from 1.6 to 3.1%.     

Fluorimetrische Bestimmung von Erythromycin-Rückständen in Lebensmitteln tierischer Herkunft nach Derivatisierung mit FMOC und HPLC-Trennung

A high-performance liquid Chromatographic (HPLC) method for the determination of the macrolide antibiotic erythromycin in eggs, milk, swine muscle, kidney and liver was developed. The drug was extracted from the matrix with acetonitrile. The raw extract was purified by liquid-liquid partitioning and fractionation by reversed-phase HPLC for additional cleanup. Erythromycin was reacted in a pre-column procedure with 9-fluorenylmethylchloroformate (FMOC) to enable fluorimetric detection (excitation 255 nm, emission 315 nm) after isocratic separation on an analytical RP-18 HPLC column. Mean recoveries ranged from 99% at fortification levels of 0.03 mg/kg in egg to 38% at 0.06 mg/kg in liver. With the exception of liver all detection limits were below 0.01 mg/kg and precision for all other matrices and tested concentrations (0.015–0.09 mg/kg) better than 20% (coefficient of variation).