提高水体中粪大肠菌群分析测试准确度的研究

粪大肠菌群的测定是一项技术并不复杂而试验条件要求却很严的生物化学测定方法。本文就粪大肠菌群检测中存在的干扰因素,采样及样品保存,实验室质量控制等全过程多方面进行探讨研究,以期提高分析的准确度及精密度。     

污泥中粪大肠菌群菌值检测方法的改进

对污泥中粪大肠菌群菌值目前通用的多管发酵法进行优化。将污泥接种到乳糖胆盐发酵管,(44.5±0.5)℃培养24 h,阳性发酵管转种到EC培养液,(44.5±0.5)℃培养24 h,查MPN检索表,求倒数算出粪大肠菌群菌值,并与优化前的国标方法进行比对。结果表明,改进后的方法比国标方法减少了平板分离和染色镜检过程,缩短了检测时间,提高了检测结果的重现性,但两者在结果上无统计学意义上的差异。改进后的多管发酵法可以用于污泥中粪大肠菌群菌值的检测。     

有机肥料粪大肠菌群指标检测时效性初探

实验室在日常肥料样品检测中,生产企业有时会提出复检粪大肠菌群指标.通过对10份肥料样品的探究性实验,研究样品保存时间和保存条件对肥料中粪大肠菌群指标检测结果的影响.结果显示,保存时间和保存条件均对肥料粪大肠菌群检测结果有影响.肥料粪大肠指标检测具有时效性,期望通过能给相关检测机构提供参考,在实际检测过程中对样品的时效性...     

酶底物法测定水中粪大肠菌群的探讨

采用酶度物法测定地表水、地下水、生活污水、工业废水的粪大肠菌群,通过试验,样品的精密度良好,标准样品的测定值在理论值范围之内。用此方法测定水中的粪大肠菌群,结果令人满意。     

多管发酵法测定污水中粪大肠菌群结果不确定度的评定

目的：研究污水处理厂污水粪大肠菌群检测结果不确定度,找出影响检测结果的主要不确定因素.方法：通过现场采集污水进行粪大肠菌群检测,对检验结果的不确定度来源作出评定.结果：本次医院污水粪大肠菌群检测不确定度为0.1601.重复性限为1.5400.结论：不确定度的分析能有效掌握检测结果的可信程度和准确性,所建立的不确定度评定方法,适合于类似粪大肠菌群检验的不确定度评定.     

环境水体中粪大肠菌群检测方法研究进展

粪大肠菌群作为水体粪便污染的指示菌,对地表水的水质监测评价具有重要作用。采取较为精确、快速的粪大肠菌群检测方法,对控制流行疾病的发生和传播有重要的科学意义。文章对检测粪大肠菌群发酵法、滤膜法、酶底物法、纸片法、聚合酶链式反应技术、荧光原位杂交技术等检测方法进行了综述。     

饮用水中特殊污染物——肠球菌检测方法

由于肠球菌引起食物中毒的现象时有报道,水环境中肠球菌也常用作指示粪便污染情况,因此,对食品和水环境中肠球菌进行检测能有效指示粪便污染情况,在评价公众健康风险等方面具有重要的意义。日益进步的微生物学、流行病学及统计学方法进一步证实:大肠杆菌不肠球菌是优于总大肠菌群和粪大肠菌群的粪便污染指示物。已有部分发达国家摒弃了总大肠菌群和粪大肠菌群等微生物指标,但目前我国还局限于粪大肠菌群作为评价地表水环境病原微生物污染的唯一指标。因此,对水中肠球菌的检测仍有很多工作要进行。     

化妆品中粪大肠菌群的检测

化妆品因其成分复杂,含有的营养物质是微生物生长的良好培养基而易导致病原微生物滋生,造成微生物的污染,而在化妆品的检测中,粪大肠菌群超标比例最高。探讨了粪大肠菌群的概念、生化特性以及检测方法。根据粪大肠菌群所具有的生物特性进行检测,挑取可疑菌落,涂片作革兰氏染色镜检。结果表明,平板上有典型菌落,并经证实为革兰氏阴性短杆菌,靛基质试验阳性,则可报告被检品中检出粪大肠杆菌。     

酶底物光谱法与酶底物法检测水中大肠菌群的比较分析

采用新型酶底物光谱法和酶底物法对不同类型水样中总大肠菌群、大肠埃希氏菌及粪大肠菌群指标进行同步检测。两种方法各有优势,采用SPSS软件对检测结果处理后进行配对t检验,结果显示：两组总大肠菌群的数据P=0.057,相关系数r=0.904;两组大肠埃希氏菌的数据P=0.593,相关系数r=0.972;两组粪大肠菌群的数据P=0.136,相关系数r=0.986,表明两种检测方法具有相关性,且没有统计学意义上的显著性差异。采用酶底物光谱法检测有证质控样品,总大肠菌群、大肠埃希氏菌、粪大肠菌群的检测结果均在质控样真值范围内,证明该方法检测准确度符合要求。酶底物光谱法与酶底物法相比,反应原理类似,操作更加简便,具有仪器自动化和智能化快速检测、判读、存储、联网传输数据等优点,可满足实验室常规检测需求,在应急突发事件现场检测方面有较强的运用前景和优势。     

酶底物法在总大肠菌群、粪大肠菌群和大肠埃希氏菌检测的适用性研究

为探讨酶底物法在三峡库区水质检测中的适用性,用酶底物法对库区地表水、污水厂出水中的总大肠菌群、粪大肠菌群和大肠埃希氏菌进行检测,测定结果 RSD<4%,测定标准菌株结果符合要求,用酶底物法和多管发酵法对不同样品进行比对,结果无统计学意义上的显著性差异(P>0.05),满足水质监测技术要求。     

Metabolism of trideuterated iso-lignoceric acid in rats in Vivo and in human fibroblasts in culture

Saturated very long chain fatty acids (fatty acids with greater than 22 carbon atoms; VLCFA) accumulate in peroxisomal disorders, but there is little information on their turnover in patients. To determine the suitability of using stable isotope-labeled VLCFA in patients with these disorders, the metabolism of 22-methyl[23,23,23-²H₃]tricosanoic (iso-lignoceric) acid was studied in rats in vivo and in human skin fibroblasts in culture. The deuterated iso-VLCFA was degraded to the corresponding 16- and 18-carbon iso-fatty acids by rats in vivo and by normal human skin fibroblasts in culture, but there was little or no degradation in peroxisome-deficient (Zellweger’s syndrome) fibroblasts, indicating that its oxidation was peroxisomal. Neither the 14-, 20-, and 22-carbon iso-fatty acids nor the corresponding odd-chain metabolites could be detected. In the rat, the organ containing most of the iso-lignoceric acid, and its breakdown products, was the liver, whereas negligible amounts were detected in the brain, suggesting that little of the fatty acid crossed the blood-brain barrier. Our data indicate that VLCFA labeled with deuterium at the ω-position of the carbon chain are suitable derivatives for the in vivo investigation of patients with defects in peroxisomal β-oxidation because they are metabolized by the same pathways as the corresponding n-VLCFA. Moreover, as iso-VLCFA and their β-oxidation products are readily separated from the corresponding n-fatty acids by normal chromatographic procedures, the turnover of VLCFA can be more precisely measured. A preliminary report of part of this work (Reference 18) was presented at the 5th International Symposium on the Synthesis and Applications of Isotopes and Isotopically Labelled Compounds, Strasbourg, France, June 20–24, 1994.     

佛山市顺德新城区降水中污染物的监测和分析

为掌握佛山市顺德新城区降水中污染物的情况,2015年7月至8月,文章作者分别在雨天进行了降水取样,对降水中的pH、电导率、常见阴离子(F-、Cl~-、NO_3~(2-)、SO_4~(2-))及部分重金属(铅和镉)进行监测分析。选择有相关数据的珠江三角洲和石家庄、厦门等地的降水中污染物的情况进行对比。结果表明,顺德新城区降水中的p H和部分阴离子浓度优于珠江三角洲平均值,酸雨类型属于硫酸和硝酸混合型;其水体洁净程度略差于石家庄;铅和镉的浓度也高于厦门,甚至部分超出了人体能直接接触的安全范围。     

Denitrification in shallow groundwater in a coastal agricultural area in Japan

In a coastal agricultural area in the central part of Japan (Shizuoka), we found decreasing nitrate concentration with depth in a shallow groundwater, where the depth to water table varied between 0.6 and 1.2 m below ground surface. High nitrate concentrations (5–29 mg N L^–1) were often observed in the upper layer (0–2 m) of the groundwater, but the concentration decreased to less than 1 mg N L^–1 in the deeper layer. Ammonium was scarcely detected, and the concentration of dissolved oxygen was usually low (< 1 mgO₂ L^–1) in the groundwater. Nitrate in the groundwater often had very heavy nitrogen stable isotope ratios (>20{}). There was a negative relationship between nitrogen stable isotope ratio of nitrate and its concentration. When nitrate was injected into the groundwater with acetylene and bromide (a conservative tracer), nitrate concentration decreased to 20% of the initial level within 5 days, accompanied by the increase in nitrite and nitrous oxide concentration and a little change in bromide concentration. These results indicate that microbial denitrification plays a potential role in the decrease of nitrate in shallow groundwater at the study site.     

我国硝酸工业生产技术新进展

系统叙述了我国硝酸工业2000-2007年生产现状及主要技术成果,尤其指出了国产"四合一"机组的成功投运,使我国硝酸国产化装置取得较大的进步,表现在吨酸的铂耗、氨耗和能耗等方面接近国外引进装置水平,同时介绍了国外双加压法硝酸生产技术的进展.我国已成为硝酸生产大国,仍需以先进的技术改造和发展我国硝酸工业,确保我国硝酸工业健康有序地发展,加快从硝酸生产大国向强国迈进的步伐.     

高效液相色谱法分析化妆品中微量成分的研究进展

综述了高效液相色谱法在化妆品中防腐剂、防晒剂中紫外线吸收剂以及性激素的检测等几个方面的应用;同时,介绍了分析所用的色谱柱、流动相、使用的检测手段以及样品的提取方法;最后针对目前存在的问题,提出了高效液相色谱用于化妆品中微量成分分析的研究方向和发展前景。