Comparison by capillary SFC and SFC-MS of soxhlet and supercritical fluid extraction of hamster feces

Components of hamster feces ranging from low molecular weight fatty acids through the expected range of triglycerides have been eluted in a single SFC run with simultaneous pressure and temperature programming. Temperature programming from 140°C to 240°C was required to provide optimum conditions for separation of the fatty acids and to move the elution region of the sterol esters away from that of the triglycerides. Data from chemical ionization and electron impact mass spectrometry of compounds separated by SFC were used to confirm identities suggested by retention measurements and to provide tentative identities of unknown compounds. SFC with flame ionization detection was used to compare Soxhlet extraction, off-line supercritical fluid extraction (SFE), and on-line SFE of the feces. Although samples obtained by Soxhlet extraction and SFE produced very similar chromatograms, SFE required far less time and consumed much smaller quantities of organic solvent.     

Analysis of thyreostats in bovine feces using ultra high performance liquid chromatography with tandem mass spectrometry

A method based on ultra‐high performance liquid chromatography was developed and validated to detect six thyreostatic compounds: tapazole, thiouracil, methylthiouracil, dimethylthiouracil, propylthiouracil, and phenylthiouracil in faeces of bovine. Thyreostats were extracted from the matrix with a mixture of methanol and buffer (pH = 8). Next step was derivatization of analytes with 3‐iodobenzylbromide. The liquid chromatographic separation of derivatives was obtained on a SB‐C18 column (50 × 2.1 mm; 1.8 μm, Agilent) with gradient elution using a mobile phase consisting of acetonitrile/0.1% acetic acid within 7.5 min. The analysis was performed on a Shimadzu NEXERA X2 ultra‐high performance liquid chromatograph with triple quadrupole MS 8050 instrument operating in positive electrospray ionization mode. Depending on the target compound, two or three diagnostic signals (selected reaction monitoring transitions) were monitored. The procedure was validated according to the Commission Decision 2002/657/EC. Recovery and repeatability met the performance criteria specified by this document for banned compounds. The recovery ranged from 97.5 to 110.5%, and repeatability did not exceed 14.1%. Decision limits and detection capabilities were below 10 μg/kg. The highest decision limits and detection capabilities concentrations were observed for phenylthiouracil of 3.48 and 6.96 μg/kg, respectively.     

Optimized Quantitative Method for Determining Isoflavones and Equol in Bovine Digestive Fluids and Feces

Many studies have been conducted on the impact of animal feed on isoflavones and their metabolite concentrations in bovine milk, but few studies have focused on the development and validation of analytical protocols for quantifying these compounds in biological matrices other than milk and plants. The purpose of this study was to develop a method that would enable four isoflavones and equol in cows’ feces and digestive fluids to be quantified simultaneously. The method is based on aglycones released by methanolic ultrasound-assisted extraction, followed by enzymatic hydrolysis and high-performance liquid chromatography tandem–mass spectrometry analysis. The sample preparation was optimized using the Box–Behnken design. The selected extraction conditions were 80°C, 10?min, and 50% methanol for digestive fluids and 70°C, 35?min, and 60% methanol for feces. For hydrolysis, the selected conditions were 37°C, 1?h, and a pH of 6 for both matrices. The analytical method showed a good linear regression model ranging from 5 to 125?ng?mL^?1. Both inter- and intraday accuracy (≤8.5 and ≤12.3%) and precision (≤11.1 and ≤15.2%) were suitable. No matrix effects were found. There was good repeatability and extract stability for at least 4 days of storage at???20 and 6°C. All recoveries were in the acceptable range of 70–120% for both matrices, except for biochanin A in feces, where the value was approximately 43%. This sensitive and reliable method will be useful for monitoring the passage of isoflavones and equol in the digestive system of ruminants.     

Development and Validation of Multi-Residue Method for Drugs Analysis in Human Feces by Liquid Chromatography–Tandem Mass Spectrometry

The use of veterinary drugs in animal production is a common practice to secure animal and human health. However, residues of administrated drugs could be present in animal food products. Levels of drugs in food of animal origin are regulated within the European Union. In recent years, residues have been detected not only in food, but also in the environmental elements such as water or soil, meaning that humans are involuntarily exposed to these substances. This article presents a multiclass method for the analysis of various therapeutic groups of pharmaceuticals in human feces. Pharmaceuticals are extracted from feces with an acid extraction solvent, and after filtration the extract was analyzed by HPLC–MS/MS. A limit of detection of 10 ng/g was achieved for 9 pharmaceuticals, with linearity over 0.99 and repeatability and reproducibility lower than 20%. The method was satisfactorily applied in 25 feces samples of individuals that had declared not to be under medical treatment for the last two months. Results indicate the presence of six different compounds at concentration between 10 and 456 ng/g. This preliminary study showed the involuntary exposure of human gut microbiota to active substances such as pharmaceuticals     

ROC曲线评价酶免法检测消化病患者幽门螺杆菌

摘要 目的 探讨消化疾病患者粪便幽门螺杆菌特异性抗原（Hp Stool antigen ,HpSA）在诊断Hp感染中的临床意义。方法 随机收集353例北京军区总医院消化内科住院和门诊患者,其中男性206例,女性147例,年龄范围14 - 89岁,平均年龄49.0? 15.73岁。入组者均空腹6小时以上,留取新鲜粪便标本,应用酶免疫法（EIA）检测HpSA,同时以13C-尿素呼气试验（13C-UBT）作为金标准。应用SPSS15.0软件对数据进行统计学分析,并绘制受试者操作特征分析曲线（Receiver Operating Characteristic curve, ROC curve）,评价HpSA试验的诊断价值。 结果 X 2 检验表明EIA法检测Hp感染与13C-UBT比较差异无显著性（p >0.05）; EIA法检测HpSA敏感度94.35%,特异度98.30%,阳性预测值98.24%,阴性预测值94.54%,阳性似然比55.5,阴性似然比0.06,符合率96.32%,Youden指数0.93,Kappa值0.93;EIA法检测HpSA的ROC曲线下面积为0.944,与完全无诊断价值的机会线下面积0.50相比差异显著（p<0.001）。结论 HpSA是一种非侵入性诊断Hp感染的方法,准确性和可靠性均较高,值得推广应用。     

Development and Validation of Liquid Chromatography-Tandem Mass Spectrometry Methods for the Quantification of Cefquinome,Ceftiofur, and Desfuroylceftiofuracetamide in Porcine Feces with Emphasis on Analyte Stability

Cefquinome and ceftiofur are β-lactam antibiotics used for the treatment of bacterial infections in swine. Although these antimicrobials are administered intramuscularly, the exposure of the gut microbiota to these cephalosporins is not well described. This exposure can contribute to the emergence and spread of antimicrobials in the environment and to the possible spread of antimicrobial resistance genes. To assess the impact of drug administration on the intestinal excretion of these antimicrobials it is essential to measure the amounts of native compound and metabolites in feces. Two (ultra)-high-performance liquid chromatography-tandem mass spectrometry ((U)HPLC–MS/MS) methods were developed and validated, one for the determination of cefquinome and ceftiofur and the other for the determination of ceftiofur residues, measured as desfuroylceftiofuracetamide, in porcine feces. The matrix-based calibration curve was linear from 5 ng g⁻¹ to 1000 ng g⁻¹ for cefquinome (correlation coefficient (r) = 0.9990 ± 0.0007; goodness of fit (gof) = 3.70 ± 1.43) and ceftiofur (r = 0.9979 ± 0.0009; gof = 5.51 ± 1.14) and quadratic from 30 ng g⁻¹ to 2000 ng g⁻¹ for desfuroylceftiofuracetamide (r = 0.9960 ± 0.0020; gof = 7.31 ± 1.76). The within-day and between-day precision and accuracy fell within the specified ranges. Since β-lactam antibiotics are known to be unstable in feces, additional experiments were conducted to adjust the sampling protocol in order to minimize the impact of the matrix constituents on the stability of the analytes. Immediately after sampling, 500 µL of an 8 µg mL⁻¹ tazobactam solution in water was added to 0.5 g feces, to reduce the degradation in matrix.     

黄雨的蜜蜂粪便说

８０年代国际上围绕黄雨问题展开了一场大论战。争论的焦点是，黄雨究竟是人造的生物／化学致毒武器，还是一种自然现象，作早在１９７７年便提出黄雨的蜜蜂粪便说，认为黄雨是一种自然现象－蜜蜂在空中净化排出的粪便。黄雨的蜜蜂粪便说现已得到国际公认，是对中国，东（老挝和柬埔寨）和马来西来黄雨的唯一令人满意的解释。本指在总结１０多年来国内外在黄雨科学这一研究领域所取得的成就和进展。     

黑麂粪便DNA的简易提取方法

收集九龙山自然保护区野外自然条件下的黑麂粪便样品,用无水乙醇保存于-70℃冰箱,经十六烷基三甲基溴化铵（CTAB）裂解液温浴粪便、酚／氯仿抽提及聚合酶链反应（PCR）纯化试剂盒纯化等步骤提取黑麂粪便DNA,并扩增线粒体DNA细胞色素b基因和2个微卫星位点进行检测;同时提取黑麂肌肉和皮毛样品的DNA作为对照．结果显示,该方法可以从粪便中提取到高质量的黑麂DNA,并可进行有效扩增,为黑麂及其他濒危鹿科动物的非损伤取样提供了一种简易方法．     

华北地区圈养大熊猫粪便中产纤维素酶芽孢杆菌菌株的分离与鉴定

为分离筛选大熊猫肠道中具有纤维素降解能力的芽孢杆菌菌株,首先对8份大熊猫粪便进行高温水浴处理,利用刚果红平板法进行初筛和复筛,DNS法测定酶活力.结果分离出126株菌株,其中8株菌株纤维素降解能力较强.结合形态特征、生理生化特征和16S rDNA序列分析,鉴定8个菌株均属于芽孢杆菌属,其中1株枯草芽孢杆菌(Bacillus subtilis),1株阿萨尔基芽孢杆菌(B.axarquienis),2株西姆芽孢杆菌(B.siamensis),4株甲基营养型芽孢杆菌(B.methylotrophicus).实验表明大熊猫肠道中存在多种降解纤维素的芽孢杆菌,其中新发现的有大熊猫源的阿萨尔基芽孢杆菌和西姆芽孢杆菌,丰富了大熊猫肠道菌群的研究,并为高效生产纤维素酶提供新的菌种来源.探究了大熊猫消化道内高效的纤维素降解菌,有利于实现高纤维类饲料资源化利用.     

牛粪挥发性成分的毛细管气相色谱分析

利用同时蒸馏萃取法提取了有治疗恶疮,霍乱效果的牛粪挥发性成分。用毛细管ＧＣ－ＭＳ联用法分离并初步鉴定了５０种组合,占总峰面积的７０．９２％,进一步步用程序升温保留指数和标准样品联合确证了其中的２４种化合物,占总峰面积的３４．６８％,与Ｓａｄｔｌｅｒ保留指数库文献数据对照又确证了另外８种化合物,占总峰面积的６．０９％。