动物组织中多种残留非类固醇同化激素的液相色谱-串联质谱法同时测定

用液相色谱-串联质谱(LC-MS/MS)同时测定动物组织中玉米赤霉醇(ZER)、玉米赤霉酮(ZEAR)、己烯雌酚(DES)、己烷雌酚(HEX)、双烯雌酚(DEN)。动物组织均质后,用叔丁基甲基醚和乙酸盐缓冲液加酶解剂分别提取试样中残留激素及代谢物,经硅胶柱净化,应用LC-MS/MS大气压化学电离负方式(APCI-),以多反应离子监测(MRM)方式进行检测,方法检测能力(CCβ)为0.143~0.496 ng.g-1。选用ZER、DES的同位素标记物作内标,内标法定量。DES、DEN在0.5~10 ng.g-1范围内回收率为58%~108%,ZER TAL、ZEAR、HEX在0.25~5 ng.g-1范围内回收率为66%~109%。     

免疫亲和固相萃取-超高效合相色谱-串联质谱法同时测定牛奶中6种玉米赤霉醇类化合物残留

建立了免疫亲和固相萃取（IAC-SPE）-超高效合相色谱-串联质谱（UPC²-MS/MS）同时测定牛奶中α-玉米赤霉醇、β-玉米赤霉醇、α-玉米赤霉烯醇、β-玉米赤霉烯醇、玉米赤霉烯酮和玉米赤霉酮残留的分析方法。样品用去离子水稀释,经IAC-SPE富集净化后,采用Waters ACQUITY UPC² Torus 2-PIC色谱柱（50 mm×3.0 mm,1.7 μm）分离,以超临界CO₂和0.1%（v/v）甲酸甲醇溶液为流动相,经梯度洗脱后在ESI^-模式下检测。经过稀释离心的牛奶样品采用免疫亲和柱净化后没有明显的基质效应,6种目标化合物在1~200 ng/mL范围内线性关系良好,相关系数（r²）≥0.9957;6种目标化合物在3个加标水平下的平均回收率为75.9%~106.5%,日内和日间精密度均≤11.4%。该法专属性好,操作简便,有机溶剂使用量小,与已有的样品测定方法比较更绿色环保,可用于牛奶中α-玉米赤霉醇、β-玉米赤霉醇、α-玉米赤霉烯醇、β-玉米赤霉烯醇、玉米赤霉酮和玉米赤霉烯酮的残留检测。     

高效液相色谱–串联质谱内标法测定动物源性食品中玉米赤霉烯酮及其代谢产物

建立高效液相色谱–串联质谱法(HPLC–MS/MS)测定动物源性食品中玉米赤霉烯酮及其5种代谢产物(α-玉米赤霉烯醇、β-玉米赤霉烯醇、α-玉米赤霉醇、β-玉米赤霉醇、玉米赤霉酮)残留量。在样品中加入4种同位素内标(13C18–玉米赤霉烯酮,D7–α-玉米赤霉烯醇,D7–β-玉米赤霉烯醇,D5–α-玉米赤霉醇)后,经β-葡萄糖苷酶/硫酸酯酶酶解,用叔丁基甲基醚萃取,取上清液氮吹至近干后用三氯甲烷复溶,再用氢氧化钠溶液反向萃取,以HLB固相萃取柱净化后,用HPLC–MS/MS检测。结果表明,玉米赤霉烯酮及其代谢产物在1.0~100.0μg/L范围内线性关系良好,相关系数均大于0.996,方法的检出限为0.04~0.13μg/kg,定量限为0.11~0.43μg/kg。在1.0、4.0、10.0μg/kg三种加标浓度水平下,回收率为77.7%~105.5%,测定结果的相对标准偏差为4.8%~9.8%(n=6)。该方法准确、可靠,灵敏度高,适用于动物源性食品中玉米赤霉烯酮及其代谢产物的定量分析。     

固相萃取-超高效液相色谱-串联质谱法检测粮食及其制品中的玉米赤霉烯酮类真菌毒素

建立了粮食及其制品中6种玉米赤霉烯酮类物质(α-玉米赤霉醇、β-玉米赤霉醇、α-玉米赤霉烯醇、β-玉米赤霉烯醇、玉米赤霉酮和玉米赤霉烯酮)的超高效液相色谱-串联质谱(UPLC-MS/MS)检测方法。样品用84%(体积分数)乙腈水溶液提取,通过ENVI-Carb石墨化炭黑(GCB)固相萃取柱进行富集净化,用6 mL二氯甲烷-甲醇(7:3, v/v)溶液洗脱,采用UPLC-MS/MS进行测定。在ACQUITY UPLCTM BEH C18反相柱上分离,梯度洗脱,流动相为水和乙腈;质谱采集模式为电喷雾负离子多反应监测模式。以α-玉米赤霉烯酮-d4为内标,6种目标物的线性范围为0.1～50 μg/L,相关系数(R2)大于0.99,检出限为0.1～0.2 μg/kg, 3个不同水平的加标平均回收率为79.9%～104.0%,相对标准偏差不大于10%。应用该方法对北京市的粮食及相关产品进行了分析,结果发现玉米赤霉烯酮的检出率最高,含量为0.42～220.7 μg/kg;此外还检出了α-和β-玉米赤霉烯醇。该方法具有操作简单、灵敏度高、重现性好等特点,符合食品样品中痕量污染物的检测要求。     

快速高分离液相色谱-串联质谱法测定植物组织中雌激素玉米赤霉醇类化合物

应用快速高分离液相色谱-串联质谱仪(RRLC-MS/MS),建立了植物组织中玉米赤霉醇类化合物(α-玉米赤霉醇、β-玉米赤霉醇、α-玉米赤霉烯醇、β-玉米赤霉烯醇、玉米赤霉酮、玉米赤霉烯酮)的检测方法.植物组织样品采用乙腈提取,碱性水溶液反萃取,经混合阴离子(MAX)固相萃取柱进行净化和富集后,用RRLC-MS/MS检测,多反应监测(MRM)模式下进行定性与定量分析.结果表明:玉米赤霉醇类化合物在0～20 μg/kg的线性范围内均具有良好的线性关系,方法检出限(LOD)为0.5 μg/kg,定量限(LOQ)为1.0 μg/kg,6种玉米赤霉醇类化合物的平均回收率为75.8%～105.4%,相对标准偏差为2.4%～12.1%.本方法可用于植物组织中玉米赤霉醇类化合物含量的测定.     

复合免疫亲和柱净化-液相色谱-串联质谱法测定动物源食品中6种黄曲霉毒素和6种玉米赤霉醇类真菌毒素残留量

建立了动物源食品(猪肉、鱼肉、猪肝)中6种黄曲霉毒素(AFB1、AFB2、AFG1、AFG2、AFM1和 AFM2)和6种玉米赤霉醇类真菌毒素(α-玉米赤霉醇、β-玉米赤霉醇、α-玉米赤霉烯醇、β-玉米赤霉烯醇、玉米赤霉酮和玉米赤霉烯酮)残留量的复合免疫亲和柱净化-高效液相色谱-串联质谱(HPLC-MS/ MS)检测方法。样品经β-葡萄糖苷酸/硫酸酯复合酶酶解后,用甲醇-乙腈(20∶80, V/ V)提取,提取液经玻璃纤维滤纸过滤,滤液用PBS 溶液稀释,复合免疫亲和柱富集和净化后,采用 HPLC-MS/ MS 法分析。12种目标分析物中 AFB2和 AFG2的线性范围为0.03~6.0μg/ L,其余目标分析物的线性范围为0.05~20μg/ L,线性相关系数均大于0.999,检出限在0.01~0.03μg/ kg 范围内,定量限在0.04~0.09μg/ kg 范围内。分别以0.5,1.0和5.0μg/ kg 添加浓度水平进行方法学验证,平均回收率为73.6%~98.4%,相对标准偏差(RSD)为1.9%~11.2%。本方法简便、灵敏,能够满足动物源食品中痕量黄曲霉毒素和玉米赤霉醇类真菌毒素残留的测定要求。     

高效液相色谱-串联质谱法同时测定动物肝脏中玉米赤霉醇及其类似物残留量

采用高效液相色谱-串联质谱方法(HPLC-MS/MS)同时测定了动物肝脏中6种玉米赤霉醇及其类似物的残留量。酶解后的样品采用乙醚提取,经液-液分配(LLP)和HLB固相萃取(SPE)柱净化后,采用HPLC-MS/MS电喷雾电离(ESI-),多反应监测(MRM)模式检测,基质匹配外标曲线定量。按照欧盟法规2002/657/EC的要求进行验证。在添加浓度1～4μg/kg范围内,方法回收率在70%～90%之间;相对标准偏差小于20%。6种玉米赤霉醇及其类似物的判断限(CCα)在0.17～0.31μg/kg之间,检测能力(CCβ)在0.26～0.42μg/kg之间。本方法对其它动物源食品中玉米赤霉醇及其类似物残留的检测具有适用性。     

复合免疫亲和柱净化-液相色谱-串联质谱法同时测定动物源性食品中6种玉米赤霉醇类化合物和氯霉素残留量

建立了动物源性食品中6种玉米赤霉醇类化合物和氯霉素残留量的复合免疫亲和柱净化、液相色谱-串联质谱（LC-MS/MS）分析方法。样品（鱼肉、肝脏、牛奶、蜂蜜）经β-葡萄糖苷酸/硫酯酸复合酶酶解后用乙醚提取,提取液经氮气吹干,残渣用50%乙腈溶液复溶后过滤,滤液用PBS溶液稀释,经复合免疫亲和柱富集净化后供LC-MS/MS检测,采用多反应监测（MRM）模式进行定量和定性分析,外标法定量。结果表明,7种目标物的检出限（S/N=3）在0.04~0.10 μg/kg之间,线性相关系数（R²）≥0.9990,平均回收率为70.9%~95.6%,相对标准偏差为2.0%~11.8%。该方法灵敏度高、重现性好,适用于动物源性食品中痕量玉米赤霉醇类药物和氯霉素残留的测定。     

免疫亲和柱净化-高效液相色谱法同时检测鸡蛋中6种玉米赤霉醇类化合物残留量

建立了鸡蛋中6种玉米赤霉醇类化合物(α-玉米赤霉醇、β-玉米赤霉醇、α-玉米赤霉烯醇、β-玉米赤霉烯醇、玉米赤霉酮和玉米赤霉烯酮)残留量的免疫亲和柱净化-高效液相色谱检测方法。样品酶解后用叔丁基甲醚提取、氢氧化钠反萃取,经免疫亲和柱富集和净化后,采用高效液相色谱-紫外检测器进行测定。色谱柱: Agilent Eclipse XDB-C18(150 mm×4.6 mm, 3.5 μm);流动相: 甲醇-乙腈-水(50:15:35, v/v/v);流速: 1.0 mL/min;检测波长: 270 nm。结果表明,6种目标物在0.01～0.2 mg/L范围内线性关系良好,相关系数(r)≥0.9998,检出限(LOD,S/N≥3)为1.0 μg/kg,平均回收率为73.2%～95.7%,相对标准偏差小于8%。该方法灵敏度高、重现性好,适用于鸡蛋样品中痕量玉米赤霉醇类药物残留的测定。     

多功能针式过滤器净化超高效液相色谱法测定大米和花生中玉米赤霉烯酮

建立了一种基于多功能针式过滤器净化的超高效液相色谱测定大米和花生中玉米赤霉烯酮的方法。样品经乙腈提取,采用多功能针式过滤器通过式净化,以超高效液相色谱法测定其中的玉米赤霉烯酮,色谱柱为ACQUITY UPLC BEH C18柱（100 mm×2.1 mm,1.7μm）,以甲醇-乙腈-水（体积比为8∶46∶46）为流动相等度洗脱,流量为0.3 mL/min,用荧光检测器检测,色谱峰面积外标法定量。玉米赤霉烯酮的质量浓度在2.5～500 ng/mL范围内与色谱峰面积线性关系良好,相关系数不小于0.999 5。大米和花生样品的方法检出限分别为15.0、30.0μg/kg,定量限分别为50.0、100.0μg/kg。样品加标回收率为77.11%～93.65%,测定结果的相对标准偏差为0.49%～4.95%(n=6)。该方法简便快速,适用于大米和花生中玉米赤霉烯酮的日常检测。     

Gas chromatography/combustion/isotope ratio mass spectrometry to control the misuse of androgens in breeding animals: new derivatisation method applied to testosterone metabolites and precursors in urine samples.

A new derivatisation reaction applied to the analysis of steroids by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) was studied. The trimethylsilylated steroids were characterised by well-resolved chromatographic signals, no peak tailing, reproducible 13C/12C measurements (0.32 per thousand, n = 28), good signal-to-noise ratio and absolute intensity (5 x 10(-9) A, 20 ng), and a slow degradation of copper oxide pellets in the combustion furnace. In addition, two new metabolites and one precursor of testosterone in bovine have been brought into consideration and used for GC/C/IRMS measurements, namely, 3beta-hydroxy-5alpha-androstan-17-one (epiandrosterone), 3beta,17alpha-dihydroxy-5alpha-androstane, and 3beta,17alpha-dihydroxy-5-androstene. The new findings have been applied to an elimination study in bovine of testosterone metabolites after an intramuscular injection of testosterone enanthate. Significant differences (up to 4 per thousand) between testosterone metabolites and precursor were detectable at least three weeks after administration.     

Determination of testosterone and its metabolites using liquid chromatography with elevated column temperature and flow-rate gradient

A rapid high performance liquid chromatography (HPLC) method for determination of testosterone and its metabolites in biological samples is described. The method combines a flow-rate gradient with elevated column temperature to obtain a complete separation of testosterone and its metabolites. The flow-rate gradient method dramatically reduces the analysis time (17 min) compared with isocratic elution (35 min). This method is simple and reproducible with relative standard deviations (R.S.D.) of <0.1% for retention time and 1-4% for peak area. It provides limits of detection (LOD) in the range of 0.05-0.1 μM for testosterone and its five major metabolites. We applied the method to analyze rat liver microsome samples incubated with testosterone, demonstrating a testosterone metabolic profile due to enzymatic activities in the microsome. Analysis of testosterone and its metabolites is important because metabolism of testosterone is a surrogate measure for cytochrome P-450 (CYP) enzymatic activity.     

N-苄基十六碳酰胺促小鼠Leydig细胞增殖和分泌睾酮的1H NMR代谢组学研究

采用基于核磁共振氢谱(¹H NMR)的细胞代谢组学技术探讨了玛咖有效成分N-苄基十六碳酰胺(NBH)促进小鼠Leydig细胞增殖和分泌睾酮的作用机制. 测定了小鼠Leydig细胞在给药前后的细胞增殖率和细胞培养液中的睾酮含量, 采用主成分分析和正交偏最小二乘判别分析, 研究了小鼠Leydig细胞在给药前后细胞破碎液中的代谢物差异, 并进行了代谢通路分析. 实验结果表明, NBH能提高小鼠Leydig细胞增殖率和睾酮分泌量, 给药后小鼠Leydig细胞破碎液中的代谢轮廓明显改变, 共鉴定亮氨酸、 赖氨酸、 鲨肌醇、 缬氨酸和丙氨酸等24种差异代谢物. 经Metaboanalyst分析发现, 差异代谢物主要涉及丙氨酸/天冬氨酸/谷氨酸代谢、 甘氨酸/丝氨酸/苏氨酸代谢、 谷胱甘肽代谢及丙酮酸代谢等10条新陈代谢和遗传信息处理代谢通路, 初步阐明了NBH通过调节上述代谢通路的相关节点发挥促进小鼠Leydig细胞增殖和分泌睾酮作用.     

Use of A New HPLC Method in Rat Liver Microsomal Testosterone Monooxygenation and Its Application to Study the Sex Dependent Expression of Several Hydroxylases

Abstract

An HPLC method described by Mancilla and Gil [Analytical Letters 17, (B9), 1984, 873-886] has been applied to study the sex dependent expression of several rat liver testosterone hydroxylases. A sample clean up procedure has been developed using SEP-PACK C- 18 cartridges which retained testosterone and its microsomal oxidative products. Undesired components were not retained or selectivly eluted with organic solvents. The clean steroid sample was eluted with a mixture of n-hexane and 2-propanol. HPLC of testosterone microsomal oxidation products was performed by normal phase In a Lichrosorb diol column using an Isocratic mixture of n-hexane and 2-propanol. The main five testosterone metabolites produced by male and female rat liver microsomes were determined In only 24 min. The turnover rates for testosterone oxidation were similar in male and female microsomes, but significant differences were observed in the rate of production of different metabolites. Male microsomes catalized mainly oxidation at positions 2 α, and 7 α; whereas female microsomes produced mainly 7 α OHT and androstenedione. These results might be explained by the different contribution of some cytochrome P-450 isozymes in microsomes from the different sexes. This method provides a useful tool to study the P-450 isozymic contributions to microsomal activities in different tissues and might facilitate the comparison of P-450 isozymes purified in different laboratories.     

Determination of the exogenous character of testosterone in bovine urine by gas chromatography-combustion-isotope ratio mass spectrometry.

A new approach was developed in order to control testosterone abuse in animal production. A gas chromatographic-combustion-isotope ratio mass spectrometric (GC-C-IRMS) method was used to distinguish the exogenous character from the endogenous character of the main metabolites of testosterone (epitestosterone and etiocholanolone) in cattle urine. This method is based on a comparison between the carbon isotope ratio (13C/12C) of testosterone metabolites and those of testosterone endogenous precursors. After urinary steroid purification, extracts were acetylated with acetic anhydride and injected into the GC-C-IRMS system. In order to validate the method, testosterone enanthate was administered to a 4 year old cow. The 13C/12C isotope ratios of testosterone exogenous metabolites appeared to be significantly different to the 13C/12C precursor ratios and were detected until 3 weeks after the anabolic administration. These preliminary results appear to be promising for the difficult control of natural hormones in livestock.     

Effects of propyphenazone and other non-steroidal anti-inflammatory agents on the synthetic and endogenous androgenic anabolic steroids urinary excretion and/or instrumental detection

This paper describes the effects of oral administration of non-steroidal anti-inflammatory drugs on the endogenous and synthetic anabolic androgenic steroids urinary excretion as assessed by gas-chromatography mass-spectrometry. Experiments were carried out on 5 male subjects, with pathologies and/or diseases, treated with non-steroidal anti-inflammatory drugs. To set up the individual baseline variability of testosterone and its main metabolites, urine samples were collected for 3 days, every 2 h prior to the administration of the drug(s); whereas the study of the effects of a single dose of each drug, here considered, on the endogenous androgen steroid urinary concentrations, was assessed by collecting urine samples for 2 days, every 2 h. Data obtained after drugs administration were then evaluated taking into account the individual baseline variability. The results showed that, only in the case of propyphenazone administration, the relative urinary concentrations of some testosterone metabolites were significantly altered. More specifically, the urinary levels of dehydroepiandrosterone, 11keto-etiocholanolone, 11β-hydroxyandrosterone, 11β-hydroxyetiocholanolone, androsterone, etiocholanolone and some metabolite ratios decrease significantly, generally between 2 and 10 h after administration of the drug, whereas no effects were observed on urinary calculated concentrations of testosterone, epitestosterone, 5α-androstane-3α,17β-diol, 5β-androstane-3α,17β-diol and testosterone/epitestosterone ratio. The observed effects do not depend on alterations on pharmacokinetics (excretion/metabolism), but on steroid sample preparation steps (hydrolysis and derivatization) inhibition. More specifically the significant decrease of dehydroepiandrosterone and testosterone metabolites urinary levels was due to a reduced yield of the steroid derivatization step for the presence in urine of the main metabolites of propyphenazone, namely hydroxyl-propyphenazone metabolites.     

A high-performance-liquid-chromatography-based method for the determination of hydroxylated testosterone metabolites formed in vitro in liver microsomes from gray seal (Halichoerus grypus)

A reproducible and sensitive high-performance-liquid-chromatography (HPLC)-based method with UV-vis detection is developed and optimized for the determination of hydroxytestosterone compounds formed via the cytochrome P450 enzyme-mediated metabolism of testosterone. The method is used to characterize and quantitate hydroxytestosterone metabolites formed in vitro via testosterone incubation with hepatic microsomes from the liver of gray seals (Halichoerus grypus). The HPLC method employs a Zorbax Eclipse XDB-C18 column (5 microm, 250- x 4.6-mm i.d.) and a combination of step gradient and solvent systems of mixtures of acetonitrile, methanol, and water. Metabolites are detected at 254 nm. The eluted peaks of 10 testosterone metabolite standards are well-resolved and a flat baseline is maintained over the elution period of the entire chromatogram. The instrumental detection limits (signal-to-noise ratio = 3) of 6beta-, 16beta-, 16alpha-, and 7alpha-hydroxytestostone and androstenedione are 14, 3, 3, 14, and 3 pmol (20 microL injection), respectively. Eleven hydroxytestosterone metabolites are detected after in vitro testosterone incubation with hepatic microsomes of gray seals. Six are identified as 6beta-, 7alpha-, 16alpha-, 16beta-, and 2beta-hydroxytestosterone and androstenedione. In order of abundance, the formation rates are 2100, 39.6, 12.8, 26.2, and 132 pmol/mg protein/min for 6beta-, 7alpha-, 16alpha-, and 16beta-hydroxytestosterone and androstenedione, respectively. The within-day precision (relative standard deviation) is less than 3% for testosterone metabolites. Five relatively substantial peaks are detected but not identified.     

Characterization of exogenous testosterone in livestock by gas chromatography/combustion/isotope ratio mass spectrometry: influence of feeding and age

The detection of exogenous testosterone in bovine urine was investigated by using gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). The carbon isotopic ratio measurement of epitestosterone, etiocholanolone (testosterone metabolite) and DHEA (testosterone precursor) in female bovine urines after testosterone enanthate administration was carried out. An important modification in the 13C/12C ratio of testosterone metabolites was observed, such that significant differences between precursor and metabolites of testosterone occurred until three weeks after intramuscular administration of testosterone enanthate. The factors influencing the 13C/12C of endogenous steroids were studied especially through cattle feeding and age. The DHEA mean delta13C value was found to vary between -25 and -26/1000 when hay and concentrate diet were used for fattening. On the other hand the delta13C value observed when maize silage was used increased to -20/1000. Testosterone metabolites showed the same delta13C increase as their precursor. Moreover, we observed a clear relationship between age and efficiency of misuse determination. Indeed, because of the lower concentration of natural hormones in young animals, the contribution of exogenous molecules increases significantly compared with older subjects. Consequently, demonstration of administration is easier to achieve in calves than in mature animals.     

Gradient HPLC separation of dehydroepiandrosterone (DHEA) from its metabolites and biological congeners: role of tetrahydrofuran in the chromatographic mechanism

A three-step gradient reversed-phase high-performance liquid chromatography (RP-HPLC) method was developed for the separation of dehydroepiandrosterone (DHEA), its sulfate ester (DHEA-S), its three C7-oxidized metabolites (7αOH-DHEA, 7βOH-DHEA, 7-keto-DHEA), and its biosynthetic congeners (androstenedione, testosterone, estradiol, pregnenolone). This new method allows the quantitative characterization of DHEA metabolism and biosynthetic transformation under given physiological, pathological, or therapeutically influenced circumstances. Tetrahydrofuran probably acts as a proton acceptor coadsorbent, while isopropanol behaves as a proton donor during the separation of testosterone, estradiol, and the stereoisomers of 7-OH-DHEA. Figure Optimized gradient RP-HPLC results in full separation of DHEA from its biosynthetic congeners and metabolites     

(1)H relaxation times of metabolites in biological samples obtained with nondestructive ex-vivo slow-MAS NMR

Methods suitable for measuring (1)H relaxation times such as T(1), T(2) and T(1rho) of metabolites in small, intact biological objects including live cells, excised organs and tissues, oil seeds etc. are developed in this work. This was achieved by combining inversion-recovery, spin-echo, or a spin-lock segment with the phase-adjusted spinning sideband (PASS) technique, which was applied at low sample-spinning rates. Here, PASS was used to produce high-resolution (1)H spectra in a nondestructive way so that the relaxation parameters of individual metabolite could be determined. The methodologies were demonstrated by measuring (1)H T(1), T(2), and T(1rho) of metabolites in excised rat liver at a spinning rate of 40 Hz.