快速消解分光光度法测定高氯废水中低浓度化学需氧量

建立快速消解分光光度法检测高氯废水中低浓度化学需氧量(COD)的方法。通过提高催化液中硫酸银的浓度(46 g/L)充分络合氯离子,同时降低消解液中重铬酸钾的浓度至0.061 2 mol/L来抑制重铬酸钾与氯离子的反应,达到有效消除Cl~–干扰的目的。水样在165℃消解30 min,于600 nm波长检测吸光度,标准曲线法计算COD。实验结果表明,水样中COD质量浓度为20 mg/L时,2 000 mg/L的Cl~–不干扰COD的测定(相对误差小于10%),并且随着COD质量浓度的增加,Cl~–产生的干扰误差逐渐降低。对国家环境保护部标准样品进行了测定,COD测定值与标准值一致。样品加标回收率为97.0%~103.7%,测定结果的相对标准偏差为2.01%~6.33%(n=6)。该法快速,有毒试剂用量小,成本低,具有较高的准确度和良好的精密度,可以用于多数工业废水中COD的测定。     

紫外消解流动注射光度法测定海水养殖废水中总氮、总磷

采用紫外消解–流动注射分光光度法测定海水养殖废水中总氮和总磷。总氮样品浓度在0.050~5.00mg/L范围内,总磷样品浓度在0.020~5.00 mg/L范围内均与峰高有良好的线性关系(r分别为0.999 90和0.999 94)。在盐度为35,进样时间为70 s,清洗时间为90 s的条件下,总氮和总磷的检出限分别为0.050mg/L和0.020 mg/L,测定结果的相对标准偏差分别为1.15%,0.60%(n=6),加标回收率分别为98.7%~101.2%和98.6%~102.5%。该方法能满足海水养殖废水中总氮和总磷的监测要求。     

碱消解-火焰原子吸收法测定土壤和固体废物中六价铬

建立了一种碱消解-火焰原子吸收法测定土壤和固体废物中六价铬的方法,讨论了碱消解过程缓冲剂用量、消解液用量以及氯化镁用量对六价铬测定的影响以及考察了三价铬共存条件下对六价铬测定的干扰情况。采用碱消解-火焰原子吸收法测定土壤和固体废物中六价铬,具有操作简单、干扰少、精密度和准确度好等优点。当取样量为1.25 g样品,消解后定容至50 m L,方法用于测定土壤和固体废物中六价铬的检出限为4.0 mg/kg,实际样品的加标回收率范围为100.4%~105.5%。     

沸水浴-氢化物发生原子荧光光谱法测定土壤中的硒

沸水浴中王水消解土壤样品,加入尿素去除HNO_3,利用盐酸铁盐作为掩蔽剂消除共存元素干扰,首次建立了氢化物发生原子荧光光谱法测定土壤中硒的快速检测方法。经国家标准物质GBW07402、GBW07404和GBW07407验证,测定结果与标准值吻合,相对标准偏差(RSD)在0.57%~1.89%之间,加标回收率为94.00%~104.67%。方法检出限和测定下限分别为0.11 ng/mL和0.37 ng/mL。与其它消解方法对比,本方法消解时间为1 h,适用于土壤中硒的快速测定。     

微顺序注射-分光光度法快速测定海水中总磷

基于微顺序注射-阀上实验室,采用磷钼蓝分光光度法测定了海水中总磷,对实验参数进行了优化,并选取了海水中主要成分离子进行了干扰实验。结果表明,海水中总磷质量浓度在0.009~1mg/L范围内与吸光度呈线性关系(r=0.9995),方法的检出限为0.003mg/L。该法测定秦皇岛黄金海岸表层海水中总磷浓度为0.090mg/L,与国标法测定结果0.088mg/L无显著性差异;测定含磷浓度为0.20mg/L的人工海水,相对标准偏差(RSD)为2.4%,样品加标回收率为94.4%~95.7%;海水中主要离子对本实验方法测定产生的干扰在5%以内。     

微波消解-电感耦合等离子体发射光谱(ICP-OES)法测生物质中的碱金属和碱土金属

为研究并解决测试生物质样品中碱金属和碱土金属含量的干扰,采用微波消解-电感耦合等离子体发射光谱(ICP-OES)法对生物质中的碱金属和碱土金属钾、钙、钠、镁元素进行测定,考察了样品消解后不同的酸体系,共存元素干扰对钾、钠、钙、镁含量测定的干扰研究。经过研究表明,接近分析标准曲线酸浓度的样品干扰小,铅、铟、钛、锰元素对钠元素测定造成干扰,砷、铜、镉对钙元素测定干扰,铝对钾元素测定有干扰,镁测定不受共存元素干扰影响,运用干扰系数法可以减少共存元素对测定元素的误差。各待测元素标准曲线相关系数大于0.9996,检出限为0.0014~0.023 mg/L,玉米芯各元素的相对标准偏差为0.98%~1.9%,加标回收率为80.2%~106%;西瓜皮的各元素相对标准偏差为0.91%~2.3%,加标回收率为85.3%~106%。方法用于测定国家标准物质GBW07603,各元素结果均在标准值参考范围内。方法用于测定生物质中碱金属和碱土金属的结果,用t检验法与离子色谱测定值进行比对,结果无显著性差异。     

微波消解-电感耦合等离子体质谱(ICP-MS)法同时测定土壤中8种重金属元素

采用微波消解-电感耦合等离子体质谱法同时测定土壤中砷、镉、铬、铜、汞、镍、铅、锌8种痕量元素,对质谱干扰和非质谱干扰进行了校正。8种重金属元素在一定的质量浓度范围内与其信号强度呈线性关系,方法的检出限(3s)在0.001 2~0.029μg/L。用加标回收测定其回收率,加标回收率范围在90.0%~96.3%,对土壤样品平行测定6次,测定值的相对标准偏差在2.1%~3.0%。对湛江南柳河附近土壤进行重金属监测,监测结果符合标准要求。     

石墨炉原子吸收分光光度法测定水中钛

建立石墨炉原子吸收分光光度法测定水中痕量可溶性钛和总钛。测量可溶性钛的样品通过0.45μm水系微孔滤膜过滤后直接测定,测量总钛的样品根据不同类型采用硝酸、过氧化氢、硫酸的不同组合进行消解。通过试验确定了最佳石墨炉程序升温工作条件和热解涂层石墨管的应用。干扰试验表明水中常见共存离子不干扰钛的测定。本方法经6家实验室验证,在0~250μg/L范围内线性良好,方法检出限可溶性钛为4.0μg/L,总钛为7.0μg/L。测定结果的相对标准偏差不大于12%(n=6),加标回收率为90.0%~107%,该方法对钛标准物质测定结果的相对误差为–3.4%~2.4%。该方法准确、可靠,检出限低,干扰少,易于推广应用。     

电感耦合等离子体质谱法测定食品中的锡

建立电感耦合等离子体质谱法测定食品中锡的方法。样品用浓硝酸冷消化后经微波消解,以纯水稀释定容消解液,选择分析目标物~(120)Sn、内标~(115)In上机测定。锡含量在0~50μg/L范围内与谱线强度线性良好,相关系数为0.999 8,检出限为0.018 mg/kg。对高、中、低3个浓度级别的样品溶液进行测定,测定结果的相对标准偏差分别为1.71%,2.42%,2.74%(n=6),样品加标回收率在98.5%~100.4%之间,该方法对实际样品的测定结果与国标法测定结果的相对偏差小于3.0%。该方法快速,干扰少,适合于食品中锡的测定。     

全自动凯氏定氮仪测定化肥中的含氮量

建立全自动凯氏定氮仪检测化肥中氮含量的分析方法。称取总氮量在0.03~0.3 g范围的样品,经消解仪消解及全自动凯氏定氮仪碱化蒸馏,以硼酸为接收液,用0.15~0.20 mol/L的盐酸标准溶液进行自动滴定。该方法加标回收率为99.0%~101.5%,测定结果的相对标准偏差小于1.0%(n=6)。与国标GB/T 8527–2010法测定结果无显著性差异,全自动凯式定氮仪法的准确度、精密度均优于国标方法,而且所用试剂少、分析时间短,满足实验室快速检测大批量化肥中含氮量的需要。     

国家监测网方法测定地表水中总磷与国标法差异及改进

比较了国家地表水环境质量监测网总磷测定方法与国标法的差异。浊度补偿与过滤两种去除浊度方法测定结果的绝对偏差为-0.02~0.07 mg/L,其中含细颗粒物较多的样品绝对偏差较大,为0.04~0.07 mg/L,因此采用过滤法时,需对含较多细颗粒物的水样进行浊度补偿。对国家地表水环境质量监测网方法进行了改进,将原来的过滤后定容改为定容摇匀后过滤。方法改进前后,样品测定值的相对偏差不大于3.4%,绝对偏差为-0.01~0.02 mg/L。改进后的方法与原方法测定结果没有显著差异,但改进后方法浊度贡献减少,试剂用量减半,而且可操作性强,更加简便和环境友好。     

电感耦合等离子体原子发射光谱法测定氟铍酸铵中的杂质元素

采用电感耦合等离子体原子发射光谱法测定氟铍酸铵中的8种主要杂质元素。以超声辅助溶解样品,然后用电感耦合等离子体原子发射光谱法测定氟铍酸铵中的钠、镁、铝、铬、铁、镍、铜、磷等8种杂质元素,8种元素线性相关系数均大于0.999,测定结果的相对标准偏差为0.65%~1.55%(n=6),检出限在0.2~19.1μg/L之间,定量范围满足氟铍酸铵中8种杂质元素的限量要求。磷的加标回收率为76.7%,其余7种杂质元素的加标回收率在80.9%~95.1%之间,测量准确度满足分析要求。将电感耦合等离子体原子发射光谱法和电感耦合等离子体质谱法进行了比较,两种方法测定结果基本一致。     

抑制电导检测离子色谱法测定双季戊四醇中总磷含量

建立了抑制电导检测离子色谱法测定工业原料双季戊四醇中总磷含量的方法.采用优化后的色谱条件对样品进行测试,该方法检测重现性好、灵敏度高、操作简便,适用于大气、水体、土壤中等总磷含量的测定.H2PO4-离子的浓度在0.01～0.5 mg/L之间与色谱峰面积呈现良好的线性关系,相关系数大于0.999.方法的检出限为3.280μg/L,样品加标测定结果的相对标准偏差小于3％(n=6),两水平平均加标回收率分别为88.2％,91.8％.     

聚硅硫酸铁絮凝剂去除市政污水磷的研究

将自制复合絮凝剂聚硅硫酸铁(PFSS i)用于市政污水除磷,考察了影响PFSS i除磷效果的一些因素,确定了PFSS i复合絮凝剂除磷的优化配比和用量。在优化条件下,对模拟污水中磷的去除率为96.7%,浊度去除率为92%;对实际污水中磷的去除率为82.3%,浊度去除率为96.5%。结果表明该复合絮凝剂有良好的除磷、除浊性能。     

Ultra-trace level determinations of benzidine and dichlorobenzidine residues in surface water by liquid chromatography-electrospray ionization tandem mass spectrometry

A liquid chromatography-electrospray ionization tandem mass spectrometric method (LC-ESI-MS/MS) has been developed for the determination of benzidine (BZ) and 3, 3′-dichlorobenzidine (DCBZ) from surface water. Parent ion of DCBZ gave strong signal with ESI by dissolving with 15?mM ammonium formate, which is also used as mobile phase. Deuterated BZ (d8-BZ) was chosen as the internal standard (IS). BZ and DCBZ were extracted by solid-phase extraction on Oasis hydrophilic-lipophilic balance (HLB) from water at pH 8.0. The coefficients of variation of BZ and DCBZ were less than 13.1% and the detection limits were 0.004?ng?L^?1 for BZ and 0.7?ng?L^?1 for DCBZ using 0.5?L surface water. The detection limit shows fair lower value than the water quality criteria for BZ and DCBZ established by the US EPA. When the proposed method was used to analyze the target compounds in sixteen surface water samples, BZ was detected in a concentration range of 0.15–2.33?ng?L^?1 in four of sixteen surface water samples     

Reverse flow injection analysis of nanomolar soluble reactive phosphorus in seawater with a long path length liquid waveguide capillary cell and spectrophotometric detection

A novel reverse flow injection analysis method coupled with a liquid waveguide capillary cell (LWCC) and spectrophotometric detection for the determination of nanomolar soluble reactive phosphorus in seawater was established. Reagent was injected into the sample stream and detected in a 2-m path length LWCC with detection wavelength set at 710 nm. Experimental parameters, including the reagent concentration, the injection volume, the flow rate and the length of the mixing coil, were optimized based on univariate experimental design. The interference of silicate and arsenate were also investigated. Under optimized conditions, the linearity and the detection limit of the proposed method were found to be 0-165.0 nM and 0.5 nM, which was estimated to be three times the standard deviation of the measurement blanks (n = 9). The relative standard deviations for the determination of 24.7 and 82.5 nM samples were 1.54% and 1.86% (n = 9), respectively. Three seawater samples were analyzed with recoveries ranging from 87.8% to 101.8%. Using the Student's t-test at the 95% confidence level, the results of the proposed method and a segmented flow analyzer reference method for determination of the two samples showed no significant difference. The proposed method had the advantages of being less reagent consuming, more sensitive and with higher throughput (15 h⁻¹).     

水中总磷和总氮含量的离子色谱测定法

采用紫外光-臭氧氧化结合离子色谱法对氧化消解后的水样同时进行总磷和总氮的测定。配制Na2CO3/NaHCO3淋洗液,采用1 mL定量环,大体积直接进样。在优化工作条件下,总磷在0.05～5.00 mg/L,总氮在0.10～10.0 mg/L范围内线性良好,线性相关系数分别为0.9999和0.9998,总磷和总氮检出限为分别3.60和4.57μg/L;总磷和总氮的检测相对标准偏差(RSD)分别低于4.9%和4.1%,总磷加标回收率为95.0%～105.0%,总氮加标回收率为93.0%～103.0%。自然环境水样检测与真实值相对偏差小于4.2%。本方法选择性好,灵敏度高,精密度和准确度高,用于实际水样中总磷和总氮含量测定的结果与国标法(GB11894-89,GB11893-89)基本一致     

Determination of uranium, iron, copper, and nickel in rock and water samples by MEKC

A micellar electrokinetic capillary chromatographic (MEKC) procedure has been developed for the separation and determination of dioxouranium (VI), iron(III), copper(II), and nickel(II) using bis(salicylaldehyde)propylenediimine (H2SA2Pn) as chelating reagent with a total run time of <3 min. Sodium dodecyl sulphate (SDS) was used as micellar medium at pH 8.1 with sodium tetraborate buffer (0.1 M). Uncoated fused silica capillary with effective length 38.8 cmx75 microm id was used with an applied voltage of 30 kV and photo-diode array detection at 228 nm. Linear calibrations were established within 0.045-1000 microg/mL of each element with detection limit within 15-122 ng/mL. The method was applied to the analysis of spring water and rock samples. The presence of uranium in rock and spring water samples was established within 1.58-1739.3 microg/g and 0.047-0.712 microg/mL with relative standard deviation within 0.9-2.1% and 1.3-2.6% respectively. Uranium ore and water samples were also assayed by the standard addition technique. Recovery of uranium was >98% with RSD up to 2.7%. Copper, nickel, and iron in their combined matrix were concurrently determined within RSD 0.6-3.6% (n=5) and the results obtained were compared with those of flame AAS.     

紫外光与臭氧结合消解-离子色谱法测定水质总磷

采用紫外光与臭氧结合消解水样,用离子色谱法测定水质总磷含量,色谱峰高与磷酸盐质量浓度在0-20mg／L范围内线性关系良好,检出限和测定下限分别0．008mg／L和0．03mg／L。此方法无需添加化学试剂,避免了标准分析方法中各种因素的影响,操作简单快速、省时,测定水质总磷的相对标准偏差为0．07％（n=5o对实际样品进行分析,总磷的加标回收率为94．5％～105．5％,表明该方法测定结果可靠,具有一定的应用价值。     

水中总磷测定各影响因素的探讨及方法优化

总磷是水体质量评价的一项重要指标,其在样品采集保存和实验室测定过程中容易受到各类干扰,历来是水质监测工作中的难点。结合实际工作中的经验,分析并探讨了水中总磷测定过程中的各类干扰因素的影响,提出了对检测各步骤进行严格控制的必要性,并对现有测定方法进行了相应优化。本文选取四类水样对优化方法进行效果验证,其方法精密度达到1.6%~3.7%,回收率达到90%~107%,检出限优于国家标准。结果表明优化方法可更准确高效地测定各类水体中的总磷,建议有利于提高水中总磷测定的效率及安全性。