超高效液相色谱串联高分辨四极杆飞行时间质谱法快速筛选鉴别猪血浆中的大环内酯类抗生素

采用超高效液相色谱串联高分辨四极杆飞行时间质谱法(UPLC-Q-TOP-MS)结合大环内酯类抗生素数据库,建立快速筛查鉴别猪血浆中常见大环内酯类抗生素的方法。猪血浆经甲醇提取,通过UPLC-Q-TOP-MS正离子模式全扫描分析,采用Agilent Extend-C18色谱柱(50×2.1 mm,1.8μm)分离,以乙腈-2 mmol/L乙酸铵水溶液(含0.1%甲酸)为流动相梯度洗脱,流速0.4 m L/min,柱温40℃,得到猪血浆中大环内酯类抗生素准分子离子峰精确质量数、主要碎片峰的精确质量数和保留时间后,结合大环内酯类抗生素数据库筛查,实现猪血浆中大环内酯类抗生素的快速定性识别。所建数据库包含26种常见猪血浆中大环内酯类抗生素的准分子离子峰精确质量数、主要碎片峰的精确质量数和保留时间,其中13种常见大环内酯类抗生素的检测限在1.00~8.00ng/g范围内。该方法分离度高、检测灵敏,可以作为快速筛查鉴别猪血浆中大环内酯类抗生素的有效方法。     

液相色谱-四极杆-静电场轨道阱高分辨质谱法测定牛奶中8种氨基糖苷类抗生素残留

建立了一种测定牛奶中链霉素、双氢链霉素、庆大霉素、大观霉素、新霉素、卡那霉素、阿米卡星和安普霉素8种氨基糖苷类药物的液相色谱-四极杆-静电场轨道阱高分辨质谱方法。样品经提取和分子印迹固相萃取柱净化,新型“液态分离池”Obelisc R色谱柱分离,1%甲酸水溶液与1%甲酸乙腈溶液作为流动相梯度洗脱,四极杆/静电场轨道阱高分辨质谱准确定性并定量。8种待测组分均获得足够的色谱保留和分离,在各自浓度范围内呈现良好的线性关系,相关系数(R²)均大于0.99,定量限在0.5～20μg/kg之间,平均回收率在68.0%～104.6%之间,批内与批间RSD均不高于11.3%。该法区别于传统方法：不添加离子对试剂,不使用含缓冲盐流动相,最大限度减少了对质谱检测器的污染;采用高分辨质谱检测器定性定量,结果准确可靠;灵敏度较现行国标显著提高。该方法具有良好的可操作性和重现性,适用于牛奶中氨基糖苷类药物的快速筛查、定性筛选和定量测定。     

高效液相色谱法检测蜂蜜中替硝唑药物残留研究

研究建立蜂蜜中替硝唑残留量的高效液相色谱测定方法。样品经12mL乙酸乙酯液液萃取、净化,在317nm波长下用二极管矩阵检测器检测。色谱柱为Agela Venusil ASB-C18(4.6×250mm,5μm),流动相甲醇∶水为17∶83(V/V),流速1.0mL/min。替硝唑浓度在0.10～4.00μg/mL范围内与峰面积呈良好的线性关系。平均回收率为82.3%～90.0%,相对标准偏差为2.27%～5.08%,方法的最低检测限10.0μg/kg。     

喹乙醇在鲫体内消除规律的研究

报道了鲫单剂量口灌50mg／kg喹乙醇在血浆、肌肉和肝胰脏中消除规律的研究。用乙腈-乙酸乙酯（1／1：V/V）提取组织中的喹乙醇,血浆中喹乙醇用3％的三氯乙酸沉淀蛋白,乙酸乙酯和磷酸盐缓冲液提取喹乙醇代谢物3-甲基喹嗯啉-2-羧酸,超高效液相色谱串联质谱法测定血浆及组织中喹乙醇及其代谢物的浓度。鲫单剂量口灌喹乙醇50mg／kg后,在血浆、肌肉和肝胰脏中的喹乙醇随着时间的延长呈现不同浓度的降解趋势。喹乙醇在血浆中的消除需要4d,在肌肉和肝胰脏中需要7d;喹乙醇的代谢物3-甲基喹嗯啉-2-羧酸在鲫体内消除比较缓慢,肌肉中需要15d,肝胰脏中需要20d。     

农业执法案件中未知粉末的分析研究

对农业执法案件中缴获的未知粉末进行分析研究。应用超高效液相色谱-飞行时间高分辨质谱（UPLC-TOF-HRMS）获得未知物分子离子峰的精确质量数、天然同位素信息,二级特征碎片的精确质荷比,并应用SCIEX PeakView及MasterView软件进行分析。经过靶向及非靶向筛查,同时参考文献报道,推导出未知粉末中的疑似化合物。采用高效液相色谱-二极管阵列检测器（HPLC-PDA）法及UPLC-TOF-HRMS法进行了双重确证。结果显示该未知粉末中含克仑特罗（16 g?kg-1）及其合成前体克仑特罗杂质B（455 g?kg-1）。本文详述的分析技术可为未知添加物的筛查和确证提供思路和技术参考。     

高效液相色谱-串联质谱法同时测定水产品中残留的12种喹诺酮和磺胺类药物

建立水产品中有12种喹诺酮类（QNs）和磺胺类（SAs）药物残留量同时测定的高效液相色谱-串联质谱方法。以氘代试剂做内标,选择乙腈提取,用正己烷脱脂,旋转蒸发浓缩,采用LC—MS／MS选择反应监测（SRM）正离子模式测定进行定性、定量分析。结果表明,12种喹诺酮类（QNs）和磺胺类（SAs）药物的检出限（LOD）为1．0μg／kg,定量限（LOQ）为2．0μg／kg,检测结果的相对标准偏差为3．5％～14．6％（n=6）,加标回收率达到69．5％～121．9％。该方法具有比较高的重现性和选择性,在水产品中喹诺酮类和磺胺类药物的残留测定中具有很好的应用前景。     

乳制品中A1 β-酪蛋白、A2 β-酪蛋白检测方法研究进展

随着消费者对A2 β-酪蛋白的关注度提升,A2 β-酪蛋白相关产品不断更新换代。A2 β-酪蛋白常用检测方法有反相高效液相色谱法（RP-HPLC）、液相色谱–高分辨串联质谱法、毛细管区带电泳法、试剂盒检测法等。本文对β-酪蛋白遗传变体A1 β-酪蛋白和原始形态A2 β-酪蛋白的功能特点、检测方法、定量分析进行综述,说明检测方法的原理和试剂药品的作用机理,加强对A1 β-酪蛋白、A2 β-酪蛋白检测方法的改进与优化,为A2 β-酪蛋白应用于功能性食品、婴幼儿配方食品提供理论依据。     

Fecal metabolite analysis of Japanese macaques in Yakushima by LC-MS/MS and LC-QTOF-MS

We performed a comprehensive fecal metabolite analysis using LC-MS/MS and LC-QTOF-MS approaches as a preliminary study. Feces of Japanese macaques on Yakushima Island were collected from five monkeys at two separate locations. Using the former methodology, 59 substances such as free amino acids, nucleotides, nucleosides and nucleic acid bases, and organic acids in the citrate cycle were quantitatively detected and successfully differentiated in two different monkey groups by the concentrations of nucleic acid metabolites and free amino acids. In the latter, around 12,000 substances were detected both by positive and negative mode in each sample. Differences in signal intensities were observed between two monkey groups in the concentrations of plant secondary metabolites such as cyanogenic glycosides, flavonoids, and phenolics.     

Nicotinic acid supplementation at a supraphysiological dose increases the bioavailability of NAD+ precursors in mares

NAD⁺ deficiency has recently been linked with increased occurrences of congenital abnormalities and embryonic death in human and animal subjects. Early embryonic death is a major component of pregnancy loss in mares and very little is known regarding the requirement for NAD⁺ in horses. The aim of this study was to quantify NAD⁺ and its metabolites in the plasma and urine of mares after orally administering an acute dose of nicotinic acid and determine the absorption, metabolism and excretion of this essential precursor for NAD⁺ biosynthesis. Nicotinic acid (5 g per os) was administered to four mares via a dosing syringe. Blood samples were collected at 0, 0.25, 0.5, 1, 2, 4, 6 and 22 h, and urine samples were collected at 0, 3, 6 and 22 h. The samples were processed and analysed by mass spectrometry. A general additive model was applied to all metabolite concentration values followed by a post-hoc multiple comparisons test. Nicotinic acid was rapidly absorbed into peripheral blood within 15 min of administration and the concentrations of nicotinic acid, nicotinamide (NAM), nicotinuric acid, nicotinic acid mononucleotide and nicotinic acid adenine dinucleotide (NaAD) increased significantly in plasma at 30 min. The concentrations of NAM, nicotinic acid riboside and NaAD increased significantly in urine at 3 h. The levels of NAM and NaAD remained significantly elevated in plasma at 22 h, sixfold and ninefold greater, respectively, than the basal levels at 0 h. While the extracellular levels of NAD⁺ in the samples remained undetected, the large, sustained elevation of NaAD levels in plasma indicates that the NAD⁺ levels were boosted within the cellular compartments. The results show that nicotinic acid supplementation increases the bioavailability of NAD⁺ precursors in mares, which is proposed to be beneficial during periods of peak NAD⁺ demand, such as during early embryo development.     

高效液相色谱-质谱联用法同时测定鸡肉中2种金刚烷胺类药物和12种喹诺酮类药物残留

为建立一种同时测定鸡肉组织中2种金刚烷胺类药物和12种喹诺酮类药物残留的高效液相色谱-质谱联用法,试验将鸡肉组织经1%乙酸的乙腈提取,乙腈饱和的正己烷脱脂,以0.1%甲酸水和甲醇为流动相进行梯度洗脱;样品质谱采用电喷雾电离,正离子扫描,多反应监测模式检测,同位素内标法定量。结果显示:14种药物在1～100 ng/mL线性范围内,线性关系良好,2种金刚烷胺类药物检出限为1μg/kg,定量限为2μg/kg,12种喹诺酮类药物检出限为5μg/kg,定量限为10μg/kg;两类药物的平均回收率在76.3%～112.6%之间,批内、批间变异系数≤12.5%。研究表明:建立的方法前处理简便,结果稳定、可靠,适用于同时检测鸡肉中金刚烷胺类药物和喹诺酮类药物残留。     

鸡蛋及牛奶中四环素类药物残留量的液相色谱-串联质谱测定法

建立了一种测定鸡蛋及牛奶中四环素类药物残留 液相色谱-串联质谱的方法。样品经Mcllvaine-Na2EDTA缓冲液提取,经快速滤纸过滤,并经加脱脂棉的HLB固相萃取柱净化,洗脱液氮气吹至小于1 mL,加30%甲醇至1mL并混匀,液相色谱-串联质谱法检测,基质匹配标液外标法定量。结果表明,四环素类药物在5 μg/kg~100 μg/kg的浓度范围内呈现良好的线性关系。在鸡蛋及牛奶中四环素类药物的检测限均为2 μg/kg,定量限均为5 μg/kg。在LOQ~2MRL(多西环素为LOQ-10LOQ)添加浓度范围内,四环素类药物的回收率均在81.2~110.0%之间,批内批间变异系数均小于11.4%。该方法各项技术指标均能满足残留检测要求,且方法的重现性良好,满足国内外兽药残留检测的相关规定。     

兽药制剂中氯霉素类和硝基呋喃类药物的液相色谱-串联质谱分析方法的研究

建立了兽药粉剂中氯霉素类和硝基呋喃类共7种抗菌药物的液相色谱-串联质谱筛选方法。样品经水溶解,乙酸乙酯提取样品中的药物,OasisHLB固相萃取小柱净化,液相色谱-串联质谱仪测定。分别对该方法的检测限和专属性进行了实验室内和实验室外验证。结果表明,该方法简单、灵敏、特异性强,适用于兽药粉剂中氯霉素类和硝基呋喃类的定性筛选测定。     

Urinary free metanephrines measurement in dogs with adrenal gland diseases using a new simple liquid chromatography tandem mass spectrometry method

Measurement of urinary metanephrines in spot samples is used for the diagnosis of canine pheochromocytoma (PC). We describe a simple analytical method based on liquid chromatography tandem mass spectrometry (LC-MS/MS) for measuring free metanephrine (MN) and normetanephrine (NMN) in spot urine samples. Using the developed method, we evaluated the stability of urinary free-MN and free-NMN at various storing conditions. In addition, we assessed the feasibility of urinary free-MN and -NMN measurement for diagnosing PC. Urine samples were mixed with stable isotope internal standards and thereafter purified by ultrafiltration. The purified samples were analyzed by LC-MS/MS in the multiple reaction monitoring mode after separation on a multimode octa decyl silyl column. The coefficient of variation of free-MN and -NMN measurement was 7.6% and 5.5%, respectively. The linearity range was 0.5–10 µg/l for both analytes. Degradation was less than 10% for both analytes under any of the storage conditions. The median free-NMN ratio to creatinine of 9 PC dogs (595, range 144–47,961) was significantly higher (P<0.05) than that of 13 dogs with hypercortisolism (125, range 52–224) or 15 healthy dogs (85, range 50–117). The developed method is simple and may not require acidification of spot urine. The results of this preliminary retrospective study suggest that the measurement of urinary free metanephrines is a promising tool for diagnosing canine PC.     

乳及乳制品中牛乳铁蛋白含量测定方法比较研究

目的 探讨两种不同检测方法测定乳与乳制品中牛乳铁蛋白的含量及应用研究。方法 对比高效液相色谱（HPLC）法和超高效液相色谱串联质谱（UPLC- MS/MS）法测定生鲜乳、调制乳、超高温瞬时灭菌乳、含乳饮料和奶粉样品等乳及乳制品中牛乳铁蛋白的含量,并对测定结果进一步比较和分析原因。结果 两种测定方法均具有较高回收率和较优的重现性,但两者方法对实际样品的测定结果具有一定差异性。结论 HPLC法测定牛乳铁蛋白是通过肝素亲和柱纯化富集乳铁蛋白,测定的是非热变性牛乳铁蛋白的含量;而UPLC-MS/MS法测定的是热变性和非热变性牛乳铁蛋白的含量,不受热处理加工工艺的影响。实验室可针对不同检测目的选择不同方法进行定量研究。     

兽药粉剂中氯霉素类和硝基呋喃类药物的液相色谱-串联质谱分析方法的研究

建立了兽药粉剂中氯霉素类和硝基呋喃类共7种抗菌药物的液相色谱-串联质谱筛选方法。样品经水溶解,乙酸乙酯提取样品中的药物,OasisHLB固相萃取小柱净化,液相色谱-串联质谱仪测定。分别对该方法的检测限和专属性进行了实验室内和实验室外验证。结果表明,该方法简单、灵敏、特异性强,适用于兽药粉剂中氯霉素类和硝基呋喃类的定性筛选测定。     

高效液相色谱-串联质谱法测定牛乳中 3 种糖肽类抗生素残留

建立牛乳中万古霉素、去甲万古霉素和替考拉宁的高效液相色谱-串联质谱测定方法。采用多反应监测模式,外标法定量。通过对不同提取溶剂的考察,选择0.1%甲酸水溶液-乙腈溶液（85∶15,V/V）作为提取溶剂;牛乳样品经超声辅助提取后,选用阳离子交换柱对万古霉素和去甲万古霉素进行净化,采用C18固相萃取柱对替考拉宁进行净化;流动相选择乙腈-0.1%甲酸水溶液体系,并采用梯度洗脱模式;分析物经反相C18色谱柱分离后,用质谱进行测定。结果表明：万古霉素、去甲万古霉素和替考拉宁的检出限分别为2、1、2 μg/kg,定量     

液相色谱串联质谱法在检测鸡肉中环丙沙星残留的应用

建立了鸡肉中环丙沙星的高效液相色谱串联质谱测定方法,试样经EDTA-Na缓冲盐提取和净化后,C18柱HPLC进行分离,多反应选择离子检测。方法的回收率和变异系数分别在90%~110%和3%~10%。该方法对鸡肉中环丙沙星检测限为1μg/kg。     

液相色谱-串联质谱测定饲料中7种硝基咪唑类药物

采用液相色谱-串联质谱法(LC-MS/MS)测定了饲料中甲硝唑(MNZ)、地美硝唑(DMZ)、洛硝唑(RNZ)、替硝唑(TNZ)、奥硝唑(ONZ)、异丙硝唑(IPZ)和塞克硝唑(SCZ)等7种硝基咪唑类药物。样品用乙酸乙酯提取,正己烷-磷酸溶液反萃取,MCX柱净化,以0.1%乙酸水溶液和乙腈作流动相进行梯度洗脱,电喷雾电离源正离子(ESI+)多反应监测(MRM)模式下检测。方法的检测限和定量限分别为0.03 mg/kg和0.1 mg/kg。添加浓度为0.1、1 mg/kg和10 mg/kg时的平均回收率为72.9%~98.8%,变异系数为4.9%~12.1%。