鸡肉、鸡蛋中4种酰胺醇类药物残留的液相色谱-三重四级杆串联质谱(UPLC-MS/MS)分析方法建立

建立了鸡肉、鸡蛋中4种酰胺醇类药物(氯霉素CAP、氟苯尼考FF、甲砜霉素TAP、氟苯尼考胺FFA)残留的超高效液相色谱-三重四级杆串联质谱(UPLC-MS/MS)快速分析方法。样品用80%的乙腈震荡提取,经过PRiME HLB固相萃取柱直接净化,在40℃下氮吹浓缩,最后用10%乙腈复溶。以0.01%甲酸水-0.01%甲酸乙腈溶液作为流动相进行梯度洗脱,采用多反应监测(MRM)模式进行测定,内标法定量。4种酰胺醇类药物在0.5~20 ng/mL的浓度范围内呈现良好的线性关系,R₂^在0.9982~ 0.9988范围内。添加量为0.5、1、5μg/kg时,鸡肉中4种酰胺醇类药物回收率为89.6%~104.2%,鸡蛋中4种酰胺醇类药物回收率为85.9%~105.5%。通过回收率和精密度试验得出该方法具有较好的准确度和重复性。通过试验得出4种酰胺醇类药物检出限为0.05~0.1 μg/kg,定量限为0.2~0.5 μg/kg,本法操作简便、灵敏,准确,适合大批量鸡肉、鸡蛋样品中4种酰胺醇类药物的检测。     

HPLC-MS/MS快速检测动物尿液中的莱克多巴胺和克伦特罗

建立了以高效液相色谱-质谱(HPLC-MS/MS)快速检测动物尿液中的莱克多巴胺和克伦特罗分析方法.样品经SCX柱净化浓缩后,以乙腈-5 mmol/L乙酸铵(65:35,V/V)为流动相,采用Kromasil CN色谱柱分离,通过电喷雾(ESI)离子源电离多反应监测(MRM)对莱克多巴胺和克伦特罗作定性和定量分析.在1.0～500.0 μg/L的范围内线性良好(r>0.999).在0.5、4.0、40.0、80.0、200.0 μg/L添加水平下,回收率在89.7%～103.3%,相对标准偏差为2.0%～7.8%.检测限(S/N=5)为0.1 μg/L.     

甘肃天祝牧区白牦牛乳脂肪中脂肪酸的分析

以甘肃天祝地区3个牧场所产的白牦牛乳为研究对象,采用气相色谱-质谱联用检测方法,测定3个牧场所产白牦牛乳中脂肪酸含量,比较在枯草期、枯草末期、返青期、青草期4个时期及不同胎次的白牦牛所产牦牛乳中脂肪酸的构成及含量.结果表明:3个牧场白牦牛乳中乳脂肪酸含量差异不显著(P＞0.05);1～5胎次母白牦牛乳中脂肪酸含量差异不显著(P＞0.05).枯草期、枯草末期、返青期、青草期4个时期白牦牛乳中饱和脂肪酸(SFA)、不饱和脂肪酸(USFA)含量比值分别为1.86、1.75、1.62、1.32.随着气温的升高及牧草的成熟,白牦牛乳中饱和脂肪酸含量逐渐降低,而不饱和脂肪酸的含量逐渐升高.     

GC/MS analysis of high-performance liquid chromatography fractions from Sophora flavescens and Torilis japonica extracts and their in vitro anti-neosporal effects on Neospora caninum

We analyzed alcoholic extracts of herbs possessing anti-neosporal activity against Neospora (N.) caninum. To identify the chemical components of Sophora (S.) flavescens and Torilis (T.) japonica associated with anti-neosporal activity, specific fractions were isolated by high-performance liquid chromatography (HPLC). In vitro activity of the fractions against N. caninum was then assessed. Gas chromatography/mass spectrometry (GC/MS) was used to identify and quantify specific anti-neosporal molecules in the herbal extracts. Almost all HPLC fractions of S. flavescens and T. japonica had higher levels of anti-neosporal activity compared to the not treated control. Active constituents of the extracts were sophoridane, furosardonin A, and tetraisopropylidene-cyclobutane in S. flavescens; 5,17-β-dihydroxy-de-A-estra-5,7,9,14-tetraene, furanodiene, and 9,12-octadecadienoic acid (Z,Z)-(CAS,1) in T. japonica.     

基于UPLC-MS/MS同时测定猪粪便中5种兽药残留量的研究

为了建立同时测定猪粪便中二甲氧苄啶、磺胺对甲氧嘧啶、恩诺沙星、金霉素、泰乐菌素5种兽药残留量的超高效液相色谱-串联质谱(UPLC-MS/MS)分析方法,样品经McIllvaineNa_2EDTA缓冲溶液提取,C18粉吸附杂质,HLB固相萃取小柱净化,浓缩富集后用0.1%甲酸甲醇溶液复溶,过滤上机,基质液外标法定量。结果显示,5种兽药在10~500μg/kg的质量浓度范围内线性良好,在添加浓度50~500μg/kg,平均回收率为53%~85%,RSD为1.87%~18.81%。该方法具有较好的准确度与精密度,能快速、准确测定猪粪便中5种兽药残留,为养殖环节实时监测兽药使用情况提供了技术支持。     

用超高效液相色谱-串联质谱检测动物源性食品中头孢喹肟残留

建立了动物源性食品中头孢喹肟残留量检测的超高效液相色谱-串联质谱法。样品经乙腈水溶液提取后,用C18固相萃取柱净化、浓缩。头孢喹肟残留量在10～500μg/L浓度范围内线性关系良好,r=0.9996。方法检测限为1 ng/g,定量限为5 ng/g。猪肌肉在5～100 ng/g空白添加浓度范围内平均回收率为57.7%～69.4%,RSD为6.68%～13.41%,猪肝在5～100 ng/g空白添加浓度范围内平均回收率为50.6%～58.6%,RSD为5.13%～12.42%,牛奶在5～40 ng/g空白添加浓度范围内中平均回收率为59.2%～65.3%,RSD为6.12%～13.26%。     

Charting the proteome of Cryptosporidium parvum sporozoites using sequence similarity-based BLAST searching

Cryptosporidium (C.) spp. are important zoonotic parasites causing widespread diarrhoeal disease in man and animals. The recent release of the complete genome sequences for C. parvum and C. hominis has facilitated the comprehensive global proteome analysis of these opportunistic pathogens. The well-known approach for mass spectrometry (MS) based data analysis using the BLAST tool (MS BLAST) is a database search protocol for identifying unknown proteins by sequence similarity to homologous proteins using peptide sequences produced by mass spectrometry. We have used several complementary approaches to explore the global sporozoite proteome of C. parvum with available proteomic tools. To optimize the output of the MS data, a sequence similarity-based MS BLAST strategy was employed for bioinformatic analysis. Most significantly, almost all the constituents of glycolysis and several mitochondrion-related proteins were identified. In addition, many hypothetical Cryptosporidium proteins were validated by the identification of their constituent peptides. The MS BLAST approach was found to be useful during the study and could provide valuable information towards a complete understanding of the unique biology of Cryptosporidium.     

QuEChERS-超高效液相色谱法-串联质谱法同时检测猪组织中赛庚啶及可乐定残留量

建立了Qu ECh ERS前处理结合超高效液相色谱-串联质谱同时检测猪组织中赛庚啶和可乐定残留量的方法。猪肉样品添加0.5 g C18粉,猪肝和猪肾样品添加3.0 g硫酸镁和2.0 g氯化钠,再分别加入10 m L 0.1%甲酸乙腈进行提取,提取液经浓缩后采用LC-MS/MS进行检测,内标法定量。该方法线性关系良好,猪肉、猪肝和猪肾中赛庚啶和可乐定在1~50μg/kg浓度范围内加标回收率分别为62%~112%和106%~121%,相对标准偏差均10%,方法检出限为0.5μg/kg。方法灵敏度高,选择性好,可作为猪组织中赛庚啶和可乐定残留量检测的确证方法。     

A filter-assisted culture method for isolation of Treponema spp. from bovine digital dermatitis and their identification by MALDI-TOF MS

Digital dermatitis (DD) is a major infectious foot disease of cattle worldwide. Some DD stages are associated with lameness, and the disease has significant economic and animal welfare consequences. The pathogenesis of the disease is not yet fully understood, but Treponema spp. have been associated consistently with clinical cases. Isolation of these fastidious bacteria is difficult and cumbersome. We describe an improved method enabling the culturing of the 3 Treponema spp. (T. pedis, T. phagedenis, and T. medium) from bovine foot specimens derived from DD lesions, using a combination of membrane filtering and subsequent growth on selective agar media. The entire procedure from sampling to verification of individual Treponema spp. takes up to 24 d. In addition, we established a MALDI-TOF MS–based identification method to be applied for confirmation of the different Treponema spp. This scheme provides an unambiguous, simple, and straightforward identification procedure for DD-associated Treponema spp.     

厄贝沙坦及其复方制剂中痕量杂质N-亚硝基-N-甲基-4-氨基丁酸残留方法学研究

采用超高效液相色谱-三重四级杆质谱(UPLC-MS/MS)建立厄贝沙坦及其复方制剂中N-亚硝基-N-甲基-4-氨基丁酸(NMBA)的测定方法。采用Waters ACQUITY UPLC○RHSS T3色谱柱进行分离,以0.005 mol/L甲酸铵(用甲酸调pH值至3.0)为流动相A,甲醇为流动相B,梯度洗脱,质谱检测器,流速为0.3 mL/min。结果显示NMBA的线性范围为0.156 6~3.132 6 ng/mL,相关系数r>0.99,方法检出限浓度为0.047 0 ng/mL(相当于样品浓度0.01μg/g),定量限浓度为0.156 6 ng/mL(相当于样品浓度0.03μg/g),样品加标回收率在80%~130%。说明该方法可以快速、简便、灵敏、准确地测定厄贝沙坦及其复方制剂中NMBA含量。