便携式傅立叶变换红外气体分析仪比对氨检测方法的探讨

采用比对方法分别用纳氏试剂分光光度法和便携式傅立叶变换红外气体分析仪检测模拟环境空气中的氨,并对检测结果进行线性相关分析,相对准确度计算以及显著性比较。这两种方法呈线性相关,无显著性差异,并具有良好的一致性。     

MetalSafe便携式分析仪快速测定水中重金属

以镉和铅为例,采用MetalSafe便携式分析仪快速测定水中重金属,介绍了基于阳极溶出伏安法的测定原理及仪器操作步骤和技术参数.采用标准加入法,镉和铅的校准曲线线性良好,检出限分别为0.022μg/L和0.025μg/L,两个质量浓度水平的镉和铅标准溶液平行测定的RSD≤0.6%,相对误差＜5%.与火焰原子吸收光谱法作...     

便携式烟气分析仪器的现状

烟气监测是大气环境监测中必不可少的项目,它是确定重点污染源并对污染源进行监视和控制的基本手段。然而过去的烟气监测,从采集样品到出分析结果要经过多个环节,不仅工作量大,而且易造成样品沾污,使数据失真。因此,采用新技术装备,以提高监测效率和数据分析的准确...     

便携式气相色谱法快速测定恶臭气体样品中的硫化物

建立一种利用便携式气相色谱仪快速、简便地测定恶臭气体样品中硫化物的方法,对硫化氢、甲硫醇、甲硫醚及二硫化碳能实现良好分离,光离子化检测器PID可实现甲硫醇、甲硫醚、二硫化碳的快速定性、定量分析,还能避免高浓度二氧化硫对测定的干扰,检出限分别为0.05、0.03、0.02ppm,精密度好,相对标准偏差RSD分别小于11.6%、7.89%和2.14%,经实际应用,效果良好。     

气体分析仪测量不确定度的分析

参照国际标准化组织颁布的\"1S0 6143:2001(E)\"标准方法,利用相对法求出回归方程,对环境气体分析仪进行了不确定度评定。分析了校准曲线图上每个校准点处的标准物质的不确定度和仪器响应值对回归直线参数的不确定度贡献,并将这些不确定度合成,给出参数的不确定度以及气体分析仪测定气体样品的不确定度。     

便携式傅立叶红外快速检测环境中气态污染物

用Calmet软件,建立了便携式傅立叶红外快速检测气态污染物的方法。该方法适用于突发性环境污染事故的应急监测。     

基于便携式悬臂梁麦克风光声光谱仪测定温室气体的方法研究

介绍了一套基于便携式悬臂梁麦克风光声光谱监测大气环境温室气体浓度的高灵敏系统,采用脉冲红外光源通过窄带光学滤光片,形成中红外区的多个光谱波段,结合光学悬臂梁麦克风技术,具有超高灵敏度,可去除背景气体干扰,实现同时监测多种气体.通过对温室气体浓度的测量,验证了甲烷(CH4)的方法检出限为0.226×10-6,二氧化碳(CO2)的方法检出限为2.624×10-6,其余的温室气体检出限最低为四氟化碳(0.052×10-6),最高为三氟化氮(0.164×10-6).同时验证了长期重复性,CO2的1倍标准偏差为0.405 5,最大漂移量为1.775 6×10-6;CH4的1倍标准偏差为9.162 0,最大漂移量为36.261 1×10-9;该仪器对CO2的最大示值偏差为-0.04×10-6,CH4的最大示值偏差为1.48×10-9.温室气体的相对标准偏差均＜2％;CO2和CH4的平均响应时间均为2 min 40 s;CO2和CH4的决定系数(R2)均＞0.999 9,CO2拟合残差在±0.05×10-6以内,CH4拟合残差在±1×10-6以内.     

傅立叶变换红外多组分气体分析仪在水污染应急监测中的应用

为了更好地为水污染应急监测工作服务,利用顶空原理,采用傅立叶变换红外多组分气体分析仪,测定水样中的有机污染物,快速筛查定性水体中主要污染物,再选用标准方法准确定量污染物浓度。结果表明,该方法具有测定范围广、仪器携带方便、筛查定性快速的优点。     

HACH分析仪测定COD的注意事项

HACH分析仪由45600型恒温反应器、DR-890型分光光度计、专用反应比色管和相应的试剂等组成,它可测定COD、NH3-N、Cr6+、NO-3-N、DO等42个常规项目。该仪器体积小、携带方便、操作简单快捷、试剂消耗少,可在现场测定。HACH分析仪测定COD的原理是在强酸介质中,重铬酸钾与水样在专用反应管中于150℃密闭回流2h,试剂中的Cr6+被水样中还原性物质还原成绿色Cr3+,在波长420nm(水样COD<150mg/L)或620nm(水样COD>150mg/L)测定Cr3+的吸光值,根据仪器内存工作曲线,可从分光光度计上直接读取水样COD值。现就COD测定中应注意的问题…     

湿度对便携式傅立叶红外快速检测气态污染物的影响

用便携式傅立叶红外对不同湿度条件下的NO2、SO2、CS2和NO进行快速检测,探讨了气体中H2O含量对该方法的影响,试验结果对突发性污染事故的应急监测具有指导意义。     

顶空便携式气相色谱-质谱仪现场测定地表水中苯系物

对顶空便携式气相色谱—质谱仪分析水中的苯、甲苯、乙苯、邻-二甲苯、间-二甲苯、对-二甲苯、异丙苯的方法进行了研究,并讨论了平衡时间、平衡温度、水中含盐量等因素对测定的影响。结果表明,方法的回收率为94.15%~98.67%,相对标准偏差为2.32%~4.88%,最低检出限为0.031~0.094μg/L。该方法快速、准确、重复性好。     

便携式气相色谱—质谱联用仪应急现场测定空气中54种VOCs

采用Inficon公司的HAPSITE四级杆气质联用仪,建立便携式气相色谱—质谱联用仪应急现场测定空气中54种挥发性有机物。对各种化合物的线性、加标回收率(56.3%~141.1%)、精密度(3.80%~22.69%)、检出限进行了测定,并将该方法运用到实际样品测定中。结果表明,该方法准确可靠、灵敏度好、分析速度快、操作简便,适用于空气中54种挥发性有机物的现场测定。     

红外分光光度法测定烟道气中油烟的探讨

结合水体石油类监测分析方法在实际应用中的经验,对饮服业油烟进行监测,并提出几点看法。     

氨气检测管的研制

经过条件优化试验,研制出氨气检测管,检测管显色长度与氨气浓度呈线性相关,对氨气标气7次测定的变异系数为11．9％,平均相对误差为7．2％,小于15％,一次测定最大相对误差为22％,小于25％,符合国家标准GB730－87的要求,与化学法比较,2种方法测试结果无显著性差异,检测管检测范围为70－500mg/m^3,有机胺产生正干扰,酸性气产生负干扰,检测管寿命为1a。     

低浓度SO2和NOx自动监测系统性能评价方法

通过对7种废气自动监测系统的比较研究和现场测试,提出了非分散红外法、紫外差分法、紫外荧光法、化学发光法等多种SO2和NO x自动监测技术在低浓度范围实现准确定量监测的性能评价方法,定义了CEMS的系统检出限及其主要影响因素。建议采用系统检出限、线性误差等关键参数作为低浓度CEMS的性能评价方法,提出将全系统多点标准气体校准或加标回收率作为验收和质控监督的基本方法。     

Monitoring of Butter and Ghee (Clarified Butter Fat) for Pesticidal Contamination from Cotton Belt of Haryana, India

Butter (45) and ghee (55) samples were collected from rural and urban areas of cotton growing belt of Haryana and analysed for detecting the residues of organochlorine, synthetic pyrethroid and organophosphate insecticides. The estimation was carried out by using multi residue analytical technique employing GC-ECD and GC-NPD systems equipped with capillary columns. Butter samples were comparatively more contaminated (97%) than ghee (94%), showing more contamination with organochlorine insecticides from urban samples. About 11% samples of butter showed endosulfan residues above MRL value and 2% samples had residues of synthetic pyrethroids and organophosphates each above their respective MRL values. In ghee, residues of HCH & DDT both and of endosulfan exceeded the MRL values in 5 and 20% samples, respectively. Among organophosphates, only chlorpyriphos was detected with 9% samples showing its residue above MRL value. Irrespective of contamination levels, residues above the MRL values were more in ghee. More extensive study covering other agricultural regions/zones of Haryana has been suggested to know the overall scenario of contamination of milk products.     

Magnitude of pesticidal contamination in winter vegetables from Hisar,Haryana

Monitoring of 80 winter vegetable samples during 1997–1998 for pesticidal contamination was carried out on GC-ECD and GC-NPD systems with capillary columns following multiresidueanalytical technique. The tested samples were found 100%contaminated with low but measurable amounts of pesticideresidues. Among the four major chemical groups, residue levels oforganophosphorous insecticides were highest followed bycarbamates, synthetic pyrethroids and organochlorines. About 32%of the samples showed contamination with organophosphorous andcarbamate insecticides above their respective MRL values. On thebasis of observations made in these studies, it is suggested thatmore extensive monitoring studies covering all vegetable cropsfrom different agro-climatic regions of the state be carried outto know exact level of pesticidal contamination, which may serveas basis for future policy on chemical use.     

Emission of nitrous oxide from rice-wheat systems of Indo-Gangetic plains of India

Nitrous oxide (N₂O) accounts for 5%of the total enhanced greenhouse effect and responsiblefor the destruction of the stratospheric ozone. The rice-wheat cropping system occupying 26 million ha ofproductive land in Asia could be a major source ofN₂O as most of the fertilizer N in this region isconsumed by this system. Emission of N₂O asinfluenced by application of urea, urea plus farm yardmanure (FYM), and urea plus dicyandiamide (DCD), anitrification inhibitor, was studied in rice-wheatsystems of Indo-Gangetic plains of India. Total emissionof N₂O-N from the rice-wheat systems varied between654 g ha^-1 in unfertilized plots and 1570 g ha^-1 in urea fertilized plots. Application of FYM and DCDreduced emission of N₂O-N in rice. The magnitude ofreduction was higher with DCD. In wheat also N₂O-Nemission was reduced by DCD. FYM applied in rice had noresidual effect on N₂O-N emission in wheat. In riceintermittent wetting and drying condition of soilresulted in higher N₂O-N emission than that ofsaturated soil condition. Treatments with 5 irrigationsgave higher emissions in wheat than those with 3irrigations. In rice-wheat system, typical of a farmer'sfield in Indo-Gangetic plains, where 240 kg N isgenerally applied through urea, N₂O-N emission is1570 g ha^-1 (0.38% of applied N) and application ofFYM and DCD reduced it to 1415 and 1096 g ha^-1,respectively.