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1.
苯系物测定方法的研究   总被引:7,自引:0,他引:7  
许涛 《四川环境》2003,22(4):44-45,48
在浓硫酸存在下,苯类化合物与甲醛反应可生成黄棕色二苯基甲烷聚合体,其浓度与显色程度成正比关系,以此进行比色测定。该有色化合物的最大吸收波长为465nm,本法的最低检出限为1.240μg/5ml,当采样体积为30L时,最低检出浓度为0.04mg/m^3。本法适用于室内环境空气的测定。研究此新测定方法的同时,与国家标准方法—气相色谱法进行了对比,对比结果显示,这两种方法相关性很好。本法具有连续性测定,方法快速、经济、简便、灵敏度高等优点。  相似文献   

2.
用示波极谱法对酚类化合物进行分析,方法的线性范围在3.0×10 ̄(-5)~8.0×10 ̄(-3)mg/L之间,最低检出限为6.0×10 ̄(-6)mg/L,浓度为0.26×10 ̄(-2)~0.52mg/L时的相对标准偏差为1.8%~4.0%,浓度为0.3×10 ̄(-2)~0.51mg/L时的回收率为95.0%~102.1%,其结果与4-氨基胺替比林分光光度法相一致。  相似文献   

3.
建立了离子色谱-抑制电导法同时检测杭州市地表水中的有机酸及无机阴离子,并对地表水中有机酸及无机阴离子的含量进行探讨.该方法的重现性(RSD)为0.15% ~4.92%,相关系数r2为0.9990 ~ 0.9999,加标回收率为84.36%~111.05%,最低检出限为0.003~0.028 mg/L.利用该建立的方法,...  相似文献   

4.
气相色谱法测定水中内吸磷   总被引:1,自引:0,他引:1  
姚朝英  杨丽莉  母应锋 《四川环境》2007,26(4):48-49,92
建立了氯仿萃取、高效毛细管柱分离、气相色谱.火焰光度检测器测定水中痕量内吸磷的方法。方法在0~200μg/L范围线性良好,内吸磷的检出限为0.1μg/L,RSD≤3.7%,平均加标回收率在90.8%~98.2%之间。  相似文献   

5.
地面水中叶枯灵的高效液相色谱测定   总被引:2,自引:0,他引:2  
本文采用反相高效液相色谱法,在质控条件下,对河水,塘水两种地面水中叶枯灵的检验方法进行了测试,用Shimapck ODS柱为分析柱,以甲醇:水=50:50为流动相,并用冰醋酸调PH至4-5,紫外检测波长281nm,两种水样的平均回收率分别为91.7-96.3%,90-95.8%,相对标准偏差为4.3%,最低检出限为0.0261mg/l,为地面水中叶枯灵卫生标准的实施提供了简便,灵敏,正确的配套测试手段。  相似文献   

6.
采用液液微萃取与气相色缈质谱法联用技术建立了测定水样中四乙基铅的方法。同时还对萃取溶剂进行选择,结果表明:选择了二氯甲烷作为萃取溶剂,氯化钠加入量10g,该方法检出限为0.03μg/L,线性范围为0.20-10.Oμg/L,线性相关系数为0.9999,测定饮用水源水和地表水中的四乙基铅,加标回收率为89.5%~101.7%,相对标准偏差为3.7%-5.9%。  相似文献   

7.
应用带TSD检测器的气相色谱仪、CP—SIL19弹性石英毛细管柱,采用固相萃取技术提取土壤中毒死蜱和阿特拉津,对土壤中的毒死蜱和阿特拉津同时测定,回收率分别为81.5%~116.7%、80.3%~118.2%,方法的变异系数1.1%~4.8%和0.9%~5.3%,方法检出限分别为阿特拉津0.0006mg·kg^-1、毒死蜱0.0004mg·kg^-1。  相似文献   

8.
利用电位滴定法在716DWS型自动电位滴定仪上实现对气田废水中Cl^-的快速、灵敏、准确测定,避免了色度、浊度的干扰。对方法的检出限、标样和实际水样精密度、准确度,进行了全面的测定分析,并与硝酸银滴定渣进行了对比。氯化物的检出限为0.32mg/L,相时标准偏差小于2.1%,加标回收率在98.9%~101%范围内,对同一标样和实际样口的测定两途中方法的结果吻合较好。  相似文献   

9.
建立了地表水中6种邻苯二甲酸酯类(PAEs)的液相色谱-串联质谱分析方法。样品直接过膜上样,用超高压液相色谱-串联质谱仪测定地表水中的邻苯二甲酸二甲酯、邻苯二甲酸二乙酯、邻苯二甲酸二丁酯、邻苯二甲酸丁基苄基酯、邻苯二甲酸二正辛酯、邻苯二甲酸二(2-乙基己基)酯。结果表明,6种PAEs线性相关性良好,方法最低检出限为0.01~ 0.05μg/L,低、中、高三个浓度的加标回收率在87.4%~106.9%之间。该方法方便、准确、灵敏度高,适合地表水中邻苯二甲酸酯类的监测分析。  相似文献   

10.
本文以二苯碳酰二脐光度法可测1~70mg/LCODCr,最低检出限为0,8mg/L,变异系数为6,2%,可用于污水处理厂出水、纯净水、饮用水、自来水等低含量CODCr。测定。  相似文献   

11.
低温捕集/热解吸气相色谱法分析废气中挥发性硫化物   总被引:1,自引:0,他引:1  
采用低温捕集/热解吸/火焰光度检测填充柱气相色谱法可分析废气中挥发性硫化物。标准气浓度为2.80g/L~38.10g/L时,硫化氢、甲硫醇、乙硫醇、甲硫醚和二甲二硫的平均回收率及相对标准偏差分别为92.1%~106.8%及0.5%~6.0%,采样体积为1.0L时,上述挥发性硫化物的最低检出浓度为0.08ng/L~0.65ng/L。该分析测定了炼油厂某些污染源和催化燃烧脱硫中试装置废气中挥发性硫化物组成,验证了方法的适用性。  相似文献   

12.
Intervention analysis is a relatively new branch of time series analysis. The power of this technique, which gives the probability that changes in mean level can be distinguished from natural data variability, is quite sensitive to the way the data are collected. The principal independent variables influenced by the data collection design are overall sample size, sampling frequency, and the relative length of record before the occurrence of the event (intervention) that is postulated to have caused a change in mean process level.For three of the four models investigated, data should be collected so that the post-intervention record is substantially longer than the pre-intervention record. This is in conflict with the intuitive approach, which would be to collect equal amounts of data before and after the intervention. The threshold (minimum) level of change that can be detected is quite high unless sample sizes of at least 50 and preferably 100 are available; this minimum level is dependent on the complexity of the model required to describe the response of the process mean to the intervention. More complex models tend to require larger sample sizes for the same threshold detectable change level.Uniformity of sampling frequency is a key consideration. Environmental data collection programs have not historically been oriented toward data analysis using time series techniques, thus eliminating a potentially powerful tool from use in many environmental assessment applications.  相似文献   

13.
利用电位滴定法在716DMS型自动电位滴定仪上实现对气田废水中C1-的快速、灵敏、准确测定,避免了色度、浊度的干扰。对方法的检出限、标样和实际水样精密度、准确度,进行了全面的测定分析,并与硝酸银滴定法进行了对比。氯化物的检出限为0.32mg/L;相对标准偏差小于等于2.1%,加标回收率在98.9%101%范围内,对同一标样和实际样品的测定两种方法的结果吻合较好。  相似文献   

14.
To date seagrass monitoring has involved the removal of seagrass from its environment. In fragile or highly disturbed systems, monitoring using destructive techniques may interfere with the environment or add to the burden of disturbance. Video photography is a form of non-destructive monitoring that does not require the removal of seagrass or interference with the environment and has the potential to be a valuable tool in monitoring seagrass systems. This study investigated the efficacy of video photography as a tool for detecting change in seagrass cover, using the temperate Australian species Amphibolis antarctica (Labill.) Sonder ex Aschers. Using visual and random point estimates of seagrass cover from video footage, it was possible to determine the minimum sample size (number of random video frames) needed to detect change in seagrass cover, the minimum detectable change in cover and the probability of the monitoring design committing a Type II error. Video footage was examined at three scales: transects (m apart), sites (km apart) and regions (tens of km apart). Using visual and random point estimation techniques, a minimum sample size of ten quadrats per transect was required to detect change in uniform and variable seagrass cover. With ten quadrats it was possible to identify a minimum detectable change in cover of 15% for uniform and 30% for variable seagrass cover. Power analysis was used to determine the probability of committing a Type II error from the data. Region level data had low power, corresponding to a high risk of committing a Type II error. Site and transect level data had high power corresponding to a low risk of committing a Type II error. Based on this study's data, managers using video to monitor for change in seagrass cover are advised to use data from the smaller scale, for example, site and transect level data. By using data from the smaller scale, managers will have a low risk of incorrectly concluding there has not been a disturbance when one has actually occurred.  相似文献   

15.
The ability to detect and to develop a precise and accurate estimate of the entrainment mortality fraction is an important step in projecting power plant impacts on future fish population levels. Recent work indicates that these mortailities may be considerably less than 100% for some fish species in the early life stages. Point estimates of the entrainment mortality fraction have been developed based on probabilistic arguments, but the precision of these estimates has not been studied beyond the simple statistical test of the null hypothesis that no entrainment mortaility exists.The ability to detect entrainment mortality is explored as a function of the sample sizes (numbers of organisms collected) at the intake and discharge sampling stations of a power plant and of the proportion of organisms found alive in the intake samples (intake survival). Minimum detectable entrainment mortality, confidence interval width, and type II error (probability of accepting the null hypothesis of no entrainment mortality when there is mortality) are considered. Increasing sample size and/or decreasing sampling mortality will decrease the minimum detectable entrainment mortality, confidence interval width, and type II error for a given level of type I error.The results of this study are considered in the context of designing useful monitoring programs for determining the entrainment mortality fraction. Preliminary estimates of intake survival and the entrainment mortality fraction can be used to obtain estimates of the sample size needed for a specified level of confidence interval width or type II error. Final estimates of the intake survival and the entrainment mortality fraction can be used to determine the minimum detectable entrainment mortality and the type II error.  相似文献   

16.
为了分析0.250 mol/L与0.025 mol/L重铬酸钾法测定炼油催化剂行业高氯废水COD的适用性,进行了比对实验。结果表明:两者测定结果相差60.5~76.8 mg/L;高浓度重铬酸钾法精密性较好, RSD%≤4.8%,准确度较高,与氯气校正法测定结果基本吻合,相对误差≤6%;低浓度的重铬酸钾法精密性相对较差, RSD%≥8.1%,与氯气校正法测定结果相对误差大于40%,准确度低。在控制稀释水样Cl-浓度500~800 mg/L范围时,采用重铬酸钾法测定COD,适宜于高浓度的方法。  相似文献   

17.
污水处理厂废水经超声粉碎后,使用TOC/TN仪直接测定总氮.对仪器条件、进样方式、微波粉碎时间及加标回收率进行了探讨.相对标准偏差<2.35%,测定结果与国标法一致,相对误差<±1.3%,回收率为95.3% ~97.8%.方法简便、快速、准确.  相似文献   

18.
Reduction-induced phosphorus (P) release from particles transported by field runoff has been poorly studied for want of a method that could be used for large surveys. To rectify this shortcoming, we modified the bicarbonate-dithionite (BD) extraction step of a sediment P speciation scheme for analyzing redox-sensitive P in runoff without sample preconcentration. The extraction comprised the addition of bicarbonate (pH buffer) and dithionite (reducing agent) into a runoff sample, 15 min of gentle shaking, filtration, and sample digestion. The samples were greatly reduced (Eh < -200 mV), and Fe and P were solubilized, but Al solubility was not increased. Phosphorus release from rock phosphates (calcium phosphates) was greater in the BD extraction than in water or bicarbonate solution, although no more than 0.2% of the total P was released. For runoff from a very fine Typic Cryaquept, the particulate phosphorus (PP) versus BD-PP relationship was linear up to a PP concentration of about 1.0 mg L(-1), but over the whole PP range studied (up to 2.6 mg L(-1)) somewhat better described by an exponential equation (BD-PP = 0.297 x PP(0.766); r2 = 0.91, n = 79). The minimum detectable value given by the method was relatively low, 0.023 mg L(-1), but reproducibility varied, with the coefficient of variation for 10 samples analyzed with 5 replicates ranging from 1.8 to 28.5%. Considering the variable reproducibility of the results and the lack of suitable reference material, the method needs further refinement and testing if it is to be used for quantitative determination of redox-sensitive P in runoff.  相似文献   

19.
There is a critical need to accurately measure the concentrations of natural steroidal estrogens in flushed dairy manure wastewater (FDMW) to assess any potential risk of waterway contamination resulting from land application. Estrogens are a concern because low concentrations (10-100 ng L-1) in water can adversely affect aquatic vertebrate species such as fish, turtles, and frogs by disrupting the normal function of their endocrine systems. The objective of this study was to develop a sample preparation method that permits the quantification of four natural steroidal estrogens (17alpha-estradiol, 17beta-estradiol, estrone, and estriol) in FDMW by gas chromatography-mass spectrometry (GC-MS). Solid-phase extraction with graphitized carbon black was used for the bulk extraction of estrogens from FDMW and additional sample purification was accomplished with C-18. The sample preparation method allowed estrogens to be detected accurately by GC-MS in FDMW. Spiked recovery experiments indicated that the method is satisfactory for measuring the estrogens of interest in FDMW with average recovery of >90%. As expected in FDMW, characterization of the estrogen profile revealed a large abundance of 17alpha-estradiol relative to 17beta-estradiol and estrone. Estriol was not detected in FDMW. The methodology developed in this research helps provide an analytical foundation for the quantification of steroidal estrogens in FDMW by GC-MS.  相似文献   

20.
对鄞州区种植的稻谷、叶菜类、水果类、豆类、茄果类和块茎类农产品按月进行了411个批次抽样,按照国家相关规定对22个农药项目进行了检测。检测结果发现样本农药项目检出率为0.3%,农产品农药残留合格率97.82%,农药残留检出项目中88.89%是杀虫剂。超出农药残留标准的样本主要是5-10月的青菜,叶菜类超标样本率达到3.72%。农药残留超标样本在平原、滨海地区种植散户中有发现,而在山区各规模农户中均有发现。小学文化程度农户样本农药残留超标率高达4.50%,是大学文化程度农户样本农药残留超标率的6.16倍。为了降低鄞州区农作物农药残留率,提出5方面的控制对策。  相似文献   

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