A simple, economical, and sensitive capillary electrophoresis (CE) method integrated with capacitively coupled contactless conductivity detection was developed for the determination of metal ions such as K<sup>+...A simple, economical, and sensitive capillary electrophoresis (CE) method integrated with capacitively coupled contactless conductivity detection was developed for the determination of metal ions such as K<sup>+</sup>, Na<sup>+</sup>, Mg<sup>2+</sup>, Sr<sup>2+</sup>, Ca<sup>2+</sup> in drinking water. 18-Crown-6 ether and Hexadecyltrimethylammonium Bromide (CTAB) were employed as complexing reagents. The effects of electrolyte additives, citric acid buffer solution, and other separation conditions of CE were comprehensively investigated and carefully optimized. The best results were obtained in a running buffer solution composed of citric acid (12 mM), 18-crown-6 ether (0.2 mM), and CTAB (0.015 mM) at pH 3.5. Under these conditions, a complete separation of five metal ions was successfully achieved in less than 12 min. The limits of detection for the optimal procedure were determined to be in the range of 0.02 - 0.2 mg·L<sup>-1</sup>. The repeatability with respect to migration times and peak areas, expressed as relative standard deviations, was better than 2.3% and 5.1%, respectively. Evaluation of the efficiency of the methodology indicated that it was reliable for the determination of metal ions in six different brands of drinking water samples.展开更多
Water leakage in drinking water distribution systems is a serious problem for many cities and a huge challenge for water utilities.An integrated system for the detection,early warning,and control of pipeline leakage h...Water leakage in drinking water distribution systems is a serious problem for many cities and a huge challenge for water utilities.An integrated system for the detection,early warning,and control of pipeline leakage has been developed and successfully used to manage the pipeline networks in selected areas of Beijing.A method based on the geographic information system has been proposed to quickly and automatically optimize the layout of the instruments which detect leaks.Methods are also proposed to estimate the probability of each pipe segment leaking （on the basis of historic leakage data）,and to assist in locating the leakage points （based on leakage signals）.The district metering area （DMA） strategy is used.Guidelines and a flowchart for establishing a DMA to manage the large-scale looped networks in Beijing are proposed.These different functions have been implemented into a central software system to simplify the day-to-day use of the system.In 2007 the system detected 102 non-obvious leakages （i.e.,14.2% of the total detected in Beijing） in the selected areas,which was estimated to save a total volume of 2,385,000 m 3 of water.These results indicate the feasibility,efficiency and wider applicability of this system.展开更多
目的了解2022年省、市、县疾控机构(Center for Disease Control and Prevention,CDC)对《生活饮用水卫生标准》(GB 5749-2006)中规定的106项指标的检测能力,分析省、市、县各指标检测能力不足的主要原因。方法收集2022年度全国各级CDC...目的了解2022年省、市、县疾控机构(Center for Disease Control and Prevention,CDC)对《生活饮用水卫生标准》(GB 5749-2006)中规定的106项指标的检测能力,分析省、市、县各指标检测能力不足的主要原因。方法收集2022年度全国各级CDC水质检测能力数据,对省级、地市级CDC的42项常规指标、64项非常规指标和对县级CDC的42项常规指标不具备检测能力的机构占比及不能检测的原因占比进行分析。结果省级CDC检测能力不足主要体现在总α放射性、总β放射性(4个省级,占比14%)和贾第鞭毛虫、隐孢子虫(6个省级,21%),主要原因均为设备配置不到位(100%),其次是无检测人员(50%~75%)。地市级CDC常规指标检测能力不足主要体现在总α放射性和总β放射性,占比均为47%;其次是消毒剂指标和消毒副产物指标(臭氧、总氯、ClO_(2)、甲醛、溴酸盐、亚氯酸盐和氯酸盐),占比为6%~22%,不具备检测能力的原因包括无设备、无标准品、无试剂和无检测人员;非常规指标中,除了氨氮(1%)外的63项指标不具备检测能力的机构占比均≥19%,其中贾第鞭毛虫和隐孢子虫不具备检测能力的机构占比最高(65%),主要原因为无设备(88%),其次为无检测人员(42%~43%)、无试剂(40%)和无标准品(38%);其余61项指标不能检测的原因为无设备、无标准品、无试剂和无检测人员(占比分别为60%~76%、45%~62%、42%~53%、51%~67%)。县级CDC常规指标中,放射性指标检测能力最弱(总α放射性和总β放射性,占比均为85%),其次是消毒剂指标和消毒副产物指标(臭氧、总氯、ClO_(2)、甲醛、溴酸盐、氯酸盐、亚氯酸盐、四氯化碳和三氯甲烷),不具备检测能力的主要原因以无设备(83%~94%)和无检测人员(53%~76%)为主。结论省、市、县CDC常规指标检测能力不足主要体现在放射性指标(省、市、县CDC),消毒剂指标(臭氧、总氯、ClO_(2))、消毒副产物指标(甲醛、溴酸盐、亚氯酸盐、氯酸盐)(市、县CDC),以及四氯化碳、三氯甲烷(县CDC);非常规指标中氨氮检测能力较好(省、市CDC),检测能力不足主要体现在贾第鞭毛虫和隐孢子虫(省、市CDC),及其他指标(市CDC)。检测能力不足的主要原因是设备配置不到位,今后应该重点从增配设备着手,增强水质检测能力。展开更多
文摘A simple, economical, and sensitive capillary electrophoresis (CE) method integrated with capacitively coupled contactless conductivity detection was developed for the determination of metal ions such as K<sup>+</sup>, Na<sup>+</sup>, Mg<sup>2+</sup>, Sr<sup>2+</sup>, Ca<sup>2+</sup> in drinking water. 18-Crown-6 ether and Hexadecyltrimethylammonium Bromide (CTAB) were employed as complexing reagents. The effects of electrolyte additives, citric acid buffer solution, and other separation conditions of CE were comprehensively investigated and carefully optimized. The best results were obtained in a running buffer solution composed of citric acid (12 mM), 18-crown-6 ether (0.2 mM), and CTAB (0.015 mM) at pH 3.5. Under these conditions, a complete separation of five metal ions was successfully achieved in less than 12 min. The limits of detection for the optimal procedure were determined to be in the range of 0.02 - 0.2 mg·L<sup>-1</sup>. The repeatability with respect to migration times and peak areas, expressed as relative standard deviations, was better than 2.3% and 5.1%, respectively. Evaluation of the efficiency of the methodology indicated that it was reliable for the determination of metal ions in six different brands of drinking water samples.
基金supported by the National Eleventh-Five Year Research Program of China(No.2006BAB17B03)
文摘Water leakage in drinking water distribution systems is a serious problem for many cities and a huge challenge for water utilities.An integrated system for the detection,early warning,and control of pipeline leakage has been developed and successfully used to manage the pipeline networks in selected areas of Beijing.A method based on the geographic information system has been proposed to quickly and automatically optimize the layout of the instruments which detect leaks.Methods are also proposed to estimate the probability of each pipe segment leaking （on the basis of historic leakage data）,and to assist in locating the leakage points （based on leakage signals）.The district metering area （DMA） strategy is used.Guidelines and a flowchart for establishing a DMA to manage the large-scale looped networks in Beijing are proposed.These different functions have been implemented into a central software system to simplify the day-to-day use of the system.In 2007 the system detected 102 non-obvious leakages （i.e.,14.2% of the total detected in Beijing） in the selected areas,which was estimated to save a total volume of 2,385,000 m 3 of water.These results indicate the feasibility,efficiency and wider applicability of this system.
文摘目的了解2022年省、市、县疾控机构(Center for Disease Control and Prevention,CDC)对《生活饮用水卫生标准》(GB 5749-2006)中规定的106项指标的检测能力,分析省、市、县各指标检测能力不足的主要原因。方法收集2022年度全国各级CDC水质检测能力数据,对省级、地市级CDC的42项常规指标、64项非常规指标和对县级CDC的42项常规指标不具备检测能力的机构占比及不能检测的原因占比进行分析。结果省级CDC检测能力不足主要体现在总α放射性、总β放射性(4个省级,占比14%)和贾第鞭毛虫、隐孢子虫(6个省级,21%),主要原因均为设备配置不到位(100%),其次是无检测人员(50%~75%)。地市级CDC常规指标检测能力不足主要体现在总α放射性和总β放射性,占比均为47%;其次是消毒剂指标和消毒副产物指标(臭氧、总氯、ClO_(2)、甲醛、溴酸盐、亚氯酸盐和氯酸盐),占比为6%~22%,不具备检测能力的原因包括无设备、无标准品、无试剂和无检测人员;非常规指标中,除了氨氮(1%)外的63项指标不具备检测能力的机构占比均≥19%,其中贾第鞭毛虫和隐孢子虫不具备检测能力的机构占比最高(65%),主要原因为无设备(88%),其次为无检测人员(42%~43%)、无试剂(40%)和无标准品(38%);其余61项指标不能检测的原因为无设备、无标准品、无试剂和无检测人员(占比分别为60%~76%、45%~62%、42%~53%、51%~67%)。县级CDC常规指标中,放射性指标检测能力最弱(总α放射性和总β放射性,占比均为85%),其次是消毒剂指标和消毒副产物指标(臭氧、总氯、ClO_(2)、甲醛、溴酸盐、氯酸盐、亚氯酸盐、四氯化碳和三氯甲烷),不具备检测能力的主要原因以无设备(83%~94%)和无检测人员(53%~76%)为主。结论省、市、县CDC常规指标检测能力不足主要体现在放射性指标(省、市、县CDC),消毒剂指标(臭氧、总氯、ClO_(2))、消毒副产物指标(甲醛、溴酸盐、亚氯酸盐、氯酸盐)(市、县CDC),以及四氯化碳、三氯甲烷(县CDC);非常规指标中氨氮检测能力较好(省、市CDC),检测能力不足主要体现在贾第鞭毛虫和隐孢子虫(省、市CDC),及其他指标(市CDC)。检测能力不足的主要原因是设备配置不到位,今后应该重点从增配设备着手,增强水质检测能力。
