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151.
Abstract

The total alkaloid content and individual alkaloid composition were determined by colorimetry and high performance liquid chroma‐tography, respectively, for Canadian rye ergot sclerotia. The total alkaloid content was highly variable between sclerotia from the same head, field, or region and ranged from 0.011 to 0.452% (av. 0.249%). Levels were lowest in ergot from Prince Edward Island. The individual alkaloid composition was uniform throughout a single sclerotium or in different sclerotia from the same head, somewhat uniform for averages in different fields throughout a region, but highly variable from head to head in a given field. On a regional basis, ergotamine followed by ergocristine were the major alkaloids observed in the east whereas the order wasreversed in the west. Ergometrine, ergosine, ergocornine, and ergocryptine were also observed to a lesser degree; ergostine was not observed. Isomerization of ergometrine increased from near 0% in the east to about 40% in the west, but was relatively constant (about 30%) for the peptide alkaloids in all regions.  相似文献   
152.
Salmonella and Escherichia coli are two bacteria that are important causes of human and animal disease worldwide. Chlorate is converted in the cell to chlorite, which is lethal to these bacteria. An HPLC procedure was developed for the rapid analysis of chlorate (ClO3 ?), nitrate (NO3 ?), and nitrite (NO2 ?) ions in bovine ruminal fluid samples. Standard curves for chlorite, nitrite, nitrate, and chlorate were well defined linear curves with R2 values of 0.99846, 0.99106, 0.99854, and 0.99138, respectively. Concentrations of chlorite could not be accurately determined in bovine ruminal fluid because chlorite reacts with or binds a component(s) or is reduced to chloride in bovine ruminal fluid resulting in low chlorite measurements. A standard curve ranging from 25 to 150 ppm ClO3 ? ion was used to measure chlorate fortified into ruminal fluid. The concentration of chlorate was more rapidly lowered (P < 0.01) under anaerobic compared to aerobic incubation conditions. Chlorate alone or chlorate supplemented with the reductants sodium lactate or glycerol were bactericidal in anaerobic incubations. In anaerobic culture, the addition of sodium formate to chlorate-fortified ruminal fluid appeared to decrease chlorate concentrations; however, formate also appeared to moderate the bactericidal effect of chlorate against E. coli. Addition of the reductants, glycerol or lactate, to chlorate-fortified ruminal fluid did not increase the killing of E. coli at 24 h, but may be useful when the reducing equivalents are limiting as in waste holding reservoirs or composting systems required for intense animal production.  相似文献   
153.
Current literature suggests that amalgam waste from dental clinics is a point-source of mercury pollution in the environment. However, apart from mercury, other amalgam constituents (e.g. Ag, Sn, Cu, and Zn) in dental clinics’ wastewater have not been reported in the literature before. The objective of this study was to evaluate the concentrations of mercury and other metals in the wastewater of some dental clinics and the influent of a wastewater treatment plant in Al-Madinah Al-Munawarah (KSA). Samples were collected over a 2-month period from three dental clinics and analyzed for metals using ICP-MS. The mean concentrations of Hg, Ag, Sn, Cu, and Zn in the samples were 5.3 ± 11.1, 0.49 ± 0.96, 3.0 ± 10.7, 10.0 ± 14.5, and 76.7 ± 106 mg L−1, respectively. Additionally, high concentrations of other metals such as Mg (14.4 ± 15.2 mg L−1), Mn (3.0 ± 4.6 mg L−1), Fe (3.0 ± 4.5 mg L−1), Sr (1.6 ± 2.4 mg L−1), and Ba (6.9 ± 10.3 mg L−1) were also found. These values are much higher than the local permissible limits. Most of the metals of interest were also detected in the influent of the wastewater treatment plant. This renders dental clinics wastewater a hazardous waste which should be properly treated before it is discharged into the environment.  相似文献   
154.
分析研究了暴马丁香不同部位中的紫丁香苷含量,为可持续合理利用和保护暴马丁香资源提供依据。利用Alltech高效液相色谱仪对暴马丁香不同部位中的紫丁香苷含量进行了测定,色谱柱为ODS-C18(4.6mm×250mm,5um),测定紫丁香苷的流动相为乙腈∶水(12∶88),体积流量1ml/min,柱温为室温,检测波长265nm。结果表明,紫丁香苷在0.1—7.0μg与峰面积具有良好的线性关系,紫丁香苷含量为韧皮部3.593%枝皮1.174%干皮1.166%木栓层0.568%枝条0.509%根0.421%木质部0.104%。该方法简便可靠、快速、重现性好,适用于暴马丁香中紫丁香苷的含量测定。  相似文献   
155.
A simple, rapid and sensitive GC–MS method for the determination of dithiocarbamate fungicide propineb [polymeric zinc propylenebis (dithiocarbamate)] and an improved HPLC procedure for the simultaneous determination of its main metabolite, propylenethiourea, and ethylenethiourea, the main metabolite of all ethylenedithiocarbamates, in airborne samples are described. The method for the analysis of propineb involves the evolution of carbon disulfide (CS2), under acidic conditions in the presence of stannous chloride, extraction of the generated CS2 into a layer of isooctane which is then analyzed for CS2 content by GC–MS in SIM mode. Under the optimum conditions, the retention time of CS2 was 1.89 min and the total time of chromatographic analysis was 5 min. Recoveries from spiking glass microfibre filters (GF/A) and silica gel filters were 86 ± 7 (n = 9) and 89 ± 4 (n = 9), respectively. The limit of detection is 0.7 ng per filter, which is equivalent to about 0.8–1.0 ng m−3 in air. In parallel, an HPLC method with ultraviolet detection is presented for the simultaneous analysis of the metabolites. Separation of the two metabolites was attained in less than 5 min. Recoveries from spiking GF/A and silica gel filters for ethylenethiourea were 100 ± 1 (n = 3) and 98 ± 2 (n = 3), respectively, while for propylenethiourea were 102 ± 1 (n = 3) and 98 ± 1 (n = 3), respectively. The detection limits are about 36–43 and 40–49 ng m−3 in air for ethylenethiourea and propylenethiourea, respectively. All the analytes spiked in the filters are proven to be stable for more than one month, at −4 °C.  相似文献   
156.
HPLC法测定水和废水中的醛酮类化合物   总被引:3,自引:0,他引:3  
将水样用1mol/L柠檬酸缓冲液调节至酸性(pH=3),其中醛酮类化合物与2,4-二硝基苯肼(DNPH)发生衍生化反应,生成稳定的化合物——腙,经C18固相萃取小柱富集、乙腈淋洗后,用带有二极管阵列检测器的高效液相色谱仪(HPLC)经32 min完成15种醛酮类化合物定性、定量分析。当测定样品为100mL时,检测限均为μg/L级,其中丙酮最高为16μg/L,丁醛最低为1.1μg/L,一般在2μg/L~6μg/L之间。  相似文献   
157.
SPE-HPLC/MS联用法测定地表水中的PFOA及PFOS含量   总被引:29,自引:0,他引:29  
张倩  张超杰  周琪  陈玲 《四川环境》2006,25(4):10-12,28
本文建立了固相萃取与高效液相色谱/质谱(HPLC/MS)联用的方法来测定地表水中全氟辛酸(PFOA)及全氟辛烷基磺酸(PFOS)的含量。此方法中PFOA在水样中的线性范围为40ng/L到500ng/L,线性相关系数0.9986,PFOS在水样中的线性范围为5n异/L到500ng/L,线性相关系数0.9905。此方法中全氟辛酸及全氟辛烷基磺酸的平均回收率分另13为83.91%和86.63%。水样中全氟辛酸和全氟辛炕基磺酸的检出限均为0.5ng/L。方法准确、可靠,分析结果令人满意。采用此方法测定了上海部分地区地表水中全氟辛酸及全氟辛烷基磺酸的含量。实验结果表明,上海地区长江入海口处徐六泾段全氟辛酸的平均浓度是46.88ng/L,全氟辛烷基磺酸未检出;黄浦江段全氟辛酸及全氟辛烷基磺酸的平均浓度分别是1594.83ng/L(前处理后需稀释10倍以确保在方法线性范围内)和20.46ng/L。可见长江及黄浦江流域的全氟辛酸及全氟辛烷基磺酸的控制与治理亟待提上议程。  相似文献   
158.
Potential synergistic interactions between polycyclic aromatic hydrocarbons in a household sewage sludge compost extract were investigated using the Dioxin-Responsive Chemical-Activated Luciferase gene eXpression (DR-CALUX) assay and reverse-phase high-performance liquid chromatography (RP-HPLC) fractionation. The biological activity of the crude extract was measured in vitro using the CALUX assay. The CALUX activity of the extract was as potent as 360-pg CALUX-TEQ (2,3,7,8-TCDD equivalent value) per g sample, this was 70 times above the WHO-TEQ value which was derived from chemical analyses of dioxins/furans and dioxin-like PCBs of the mixture. The CALUX activity pattern of the crude extract and the retention times of 26 polycyclic aromatic compounds (PACs), as determined by RP-HPLC on an octadecylsilica column, suggested that the dioxin-like compounds with the log K(OW) (n-octanol/water partition coefficient) values corresponding to 6.0-7.0 contributed highly to the whole activity. The CALUX activity of the crude extract was three times the sum of the CALUX activities of the RP-HPLC separated fractions. Mixture effects were assessed by co-exposure of each HPLC fraction and 2,3,7,8-TCDD to the cells. The four concentration levels of added 2,3,7,8-TCDD corresponded to the TEQ value in the original compost sample. The experimental CALUX activity was higher than the predicted CALUX activity for some fractions. It was demonstrated that some compounds in the compost sample interacted synergistically with 2,3,7,8-TCDD in terms of dioxin-like activity. This finding points out the necessity for detailed investigation of synergistic effects in environmental samples.  相似文献   
159.
北京市大气甲醛浓度研究   总被引:10,自引:1,他引:9  
分别于2006年7, 9, 12月和2007年3月采用2, 4-二硝基苯肼(DNPH)高效液相色谱法测定了北京市大气中的φ(甲醛).结果表明:在观测期间,春、夏、秋、冬各季φ(甲醛)的平均值分别为7.56×10-9, 12.70×10-9和 7.24×10-9,3.34×10-9;夏季φ(甲醛)明显高于其他3个季节, 春、秋φ(甲醛)平均值非常接近, 冬季φ(甲醛)最低;夏季φ(甲醛)与 φ(O3), 温度,UVB的日变化表现出良好的一致性,均在12:00—15:00出现高值;夏季φ(甲醛)主要受光化学氧化过程的控制和影响; 降水对大气甲醛有明显的清除作用.   相似文献   
160.
31P NMR与HPLC联用筛选高效有机磷降解细菌   总被引:7,自引:0,他引:7  
从有机磷农药污染地区分离到14株具有高效甲胺磷降解活力的细菌,并用HPLC对其降解效率进行分析,发现一周内降解率最高达74%.采用^31 PNMR对其降解产物进行了同步监测,发现其降解产物不同,其中有三株可以把甲胺磷代谢成磷酸.这三株降解细菌可以从环境中有效的清除有机磷的污染.  相似文献   
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