环境水样中总磷分析方法及仪器的研究进展

磷是生物不可或缺的营养元素之一,但由于人类活动影响,在地表水和近岸海水中总磷一直是主要污染指标。总磷测定通常分两步进行：一是将水样中各种不同形态的磷消解转化为可被检测的磷酸盐;二是测定消解后样品中的磷酸盐浓度。消解方法有硫酸-硝酸消解法、干法灰化法、微波辅助消解法、过硫酸钾-高温高压消解法、UV光氧化法等。测定方法包括电化学法、化学发光法、磷钼蓝分光光度法、磷钒钼黄分光光度法等。目前应用最为广泛的是过硫酸钾-高温高压消解法和磷钼蓝分光光度法。总磷测定仪器通常基于该消解法和测定法而开发,可分为用于实验室的水样离线分析仪和用于水体现场的在线分析仪两类。该综述总结了近20年来环境水样中上述总磷分析方法及仪器的研究进展,比较了各方法和仪器的特点,并分析了总磷分析方法和分析仪器的发展趋势。     

基于钼酸盐光度法测定总磷的浊度去除方法

采取新的浊度去除方法,改进了测定总磷的钼酸盐光度法。测定过程中,消解液的浊度会对测定结果产生干扰。通过比较机械过滤法和试剂补偿法的浊度校正效果,建立了中速定性滤纸单次机械过滤的浊度去除方法,确定了最佳去除条件:控制待滤液温度不高于30℃,清洗纯水的体积不少于20 m L。选择消解液具有浊度干扰项的6种代表性水样,分别进行平行测定和加标回收试验,方法检出限为0.008 mg/L,测定结果的相对标准偏差为2.8%~7.9%(n=6),加标回收率为92.0%~106%。该方法灵敏度、准确度高,精密度良好,与现行国标法相比,试剂消耗量少,分析效率高,能够满足多种水环境样品中总磷的测定要求。     

微波消解-磷钼蓝分光光度法测定城市污泥中总磷浓度

建立了微波消解-磷钼蓝分光光度法测定城市污泥中总磷的方法。在微波环境中硝酸-过氧化氢能够将城市污泥中无机磷盐和含磷有机物消解为正磷酸盐,在弱酸性条件下,正磷酸盐在铋盐的催化条件下与钼酸铵-抗坏血酸生成磷钼蓝,于分光光度计波长690nm处进行测定总磷浓度。方法的相对标准偏差0.63%～0.95%,加标回收率为101%～102%,能够满足对城市污泥中总磷浓度的测定要求。     

流动注射光度法测定水中总磷方法的改进

对全自动流动注射分析仪的分析流路进行了改进,将先消解后进样的模式改为先进样后消解的模式,提出了一种改进的流动注射光度法测定水中总磷含量的方法。总磷的质量浓度在0.01～2.0mg.L-1范围内与吸光度呈线性关系,检出限(3S/N)为1.4μg.L-1。方法用于水样中总磷的测定,经t-检验测定值与国标法测定值无显著差异。水样的加标回收率在93.0%～105.0%之间。     

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。     

微波消解测定水样中总磷

研究了以H2O2-HNO3为氧化剂，用微波消解测定水样中总磷的分析方法。通过正交试验选择合适的消解条件与氧化剂投入量，选择合适的显色酸度及测定波长，方法对自然水样测定平均相对标准偏差为3．3％，平均回收率为100．3%。     

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     

三价铬对COD测定中Cl~–干扰的抑制

测定含氯量高而化学需氧量较低的水样时,在消解过程中利用含Cr3+的硫酸银–硫酸试剂代替国标法中的硫酸银–硫酸试剂,结果表明,用改进法测定含氯且低COD的水样时,Cl–的干扰小于国标法;测定无氯或含氯且COD大于375 mg/L的水样,两种方法测定结果几乎无差别。测定COD 100 mg/L,Cl–质量浓度为1 000 mg/L的水样,相对偏差由国标法的25.8%下降到8.4%;改进法测定COD 100 mg/L,Cl–质量浓度分别为2 000,3 000,5 000mg/L的水样,相对偏差分别为6.3%,11.4%,15.0%,均优于含氯1 000 mg/L国标法测定结果。改进法在COD测定下限的氧化电位相当于国标法测定的COD上限电位,测定上限的氧化电位比国标法下降了0.008 3 V。该方法用于测定含氯高的低COD水样,可抑制Cl–的干扰,提高测量结果的准确度。     

HACH替代试剂测定低COD浓度水样的实验研究

为节省测试费用,选择HACH的替代试剂对水样进行消解,而后用反应管在HACH分光光度计上比色测定,产生的误差较大.对消解样品改用滴定的分析方法,实验结果与传统回流法一致,两者的相对误差在5%之内,另外用该方法对4组标准水样进行测定,相对偏差均小于10%,准确度也0.04%～3.35%的范围内.该替代方法具有试剂用量少、成本低、操作简便等优点,适合在室内进行批量测试.     

水质监测中总磷无损的近红外光谱分析研究

本文对天然水样的近红外光谱与水样总磷（TP）含量进行了相关性研究,并建立了水质总磷的近红外光谱（NIRS）分析方法。结果表明：NIRS方法建立的定量分析模型所得TP含量与国标法得到结果的相关性达到0.908,并且在显著性水平大于0.05的条件下对NIRS方法与国标法的测定结果进行t检验,二者无显著性差异,说明了NIRS方法定量分析地表水中低含量总磷的可行性。     

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。     

Indirect atomic-absorption spectrophotometric determination of phosphorus after flotation as the ion-pair of molybdophosphate with bis[2-(5-chloro-2-pyridylazo)-5-diethylaminophenolato]cobalt(III)

An atomic-absorption spectrophotometric method has been developed for the indirect determination of phosphorus. The calibration graph is linear over the range 0.025-0.2 mug of phosphorus. The relative standard deviation is 1.3% for 0.2 mug of phosphorus (6 replicates). The method has been applied to the determination of phosphate in natural water samples. The enhancement effect of acetone on the determination is discussed.     

封闭溶样-电感耦合等离子体质谱法测定地质样品中痕量金

建立了聚乙烯塑料瓶封闭水浴加热,王水溶解,以铼作内标,电感耦合等离子体质谱法测定地质样品中痕量金。结果表明,样品中的金可分解完全,节约了成本、减少了环境污染。方法经国家一级标准物质验证,结果与标准值相符。对实际样品测定的方法相对标准偏差(RSD,n=9)为4.1%～6.7%。方法检出限为0.12ng/g,方法简便快速,适用于地质样品的批量分析。     

Simple and rapid determination of phosphorus in meat samples by WD-XRF method

The wavelength dispersive X-ray fluorescence (WD-XRF) method for phosphorus determination in meat samples has been described. The effects of sample pretreatment on the XRF analysis have been discussed. The phosphorus content determined in meat samples ranged from 603 ± 6 to 613 ± 19 mg P/100g dry mass (d.m.), depending on the sample preparation technique. The meat samples spiked with phosphates have been used for the calibration procedure. The accuracy was determined against a number of certified reference materials (SMRD 2000, RF 8414, NIST-1568A, and NIST-1549), and recovery was assayed using the standard addition procedure. The proposed method has been compared with the standard spectrophotometric method (PN-ISO 13730, 1999) of total phosphorus determination. The sample pretreatment procedure has been reduced to minimum the presented results suggest the WD-XRF method can be an alternative to the spectrophotometric analysis.     

Determination of trace phosphorus in high purity tantalum materials by inductively coupled plasma mass spectrometry subsequent to matrix separation with on-line anion exchange/coprecipitation

An on-line matrix separation/inductively coupled plasma mass spectrometry (ICP-MS) method is proposed for the determination of trace amounts of phosphorus in high purity tantalum metal, tantalum (V) oxide, and tantalum pentaethoxide. In the present method, the matrix tantalum in the sample solution was adsorbed on the anion exchange resin, and phosphorus (phosphate ion) was eluted with the carrier solution of HF and HNO3 mixture. Then, the effluent solution was subsequently mixed with bismuth solution and aqueous ammonia solution to coprecipitate phosphate together with bismuth hydroxide. The precipitate formed was collected on the in-line membrane filter to wash out nitric acid with pure water, and then dissolved with hydrochloric acid. The obtained phosphorus sample solution was introduced directly into the nebulizer of ICP-MS for the determination of phosphorus. Phosphorus was determined at the molecular ion signal of 31P16O+ (m/z 47). The detection limit (3sigma) of phosphorus in the present method was 1.3 ng mL(-1) as the sample solution basis, and the relative standard deviation for 30 ng mL(-1) of phosphorus in the standard solution was 4.3% in the replicate measurements (n=11). The present method was applied to the analysis of high purity tantalum materials. The concentrations of phosphorus in tantalum samples were in fairly good agreement with those obtained by glow discharge mass spectrometry (GDMS).     

国标法测定地表水中阴离子表面活性剂方法优化

对GB/T 7494–1987测定地表水中阴离子表面活性剂含量的方法进行优化。对萃取次数、磷酸二氢钠溶液反洗以及pH调节等进行了试验研究,将萃取用的三氯甲烷总量降为25 mL,两次萃取定容后一次反洗。结果表明,萃取两次可以满足分析需求,反洗能够有效去除亚硝酸盐氮等离子干扰,中性地表水样品无需调节pH,非中性样品须调为中性后测定。方法优化后线性良好,线性相关系数大于0.999,检出限为0.012 mg/L。测定结果的相对标准偏差为0.8%~3.3%(n=6),加标回收率为92.0%~110.0%。优化后方法满足地表水分析要求,能有效降低三氯甲烷用量并简化分析步骤。     

Fully automated standard addition method for the quantification of 29 polar pesticide metabolites in different water bodies using LC-MS/MS

A reliable quantification by LC-ESI-MS/MS as the most suitable analytical method for polar substances in the aquatic environment is usually hampered by matrix effects from co-eluting compounds, which are unavoidably present in environmental samples. The standard addition method (SAM) is the most appropriate method to compensate matrix effects. However, when performed manually, this method is too labour- and time-intensive for routine analysis. In the present work, a fully automated SAM using a multi-purpose sample manager “Open Architecture UPLC®-MS/MS” (ultra-performance liquid chromatography tandem mass spectrometry) was developed for the sensitive and reliable determination of 29 polar pesticide metabolites in environmental samples. A four-point SAM was conducted parallel to direct-injection UPLC-ESI-MS/MS determination that was followed by a work flow to calculate the analyte concentrations including monitoring of required quality criteria. Several parameters regarding the SAM, chromatography and mass spectrometry conditions were optimised in order to obtain a fast as well as reliable analytical method. The matrix effects were examined by comparison of the SAM with an external calibration method. The accuracy of the SAM was investigated by recovery tests in samples of different catchment areas. The method detection limit was estimated to be between 1 and 10 ng/L for all metabolites by direct injection of a 10-μL sample. The relative standard deviation values were between 2 and 10 % at the end of calibration range (30 ng/L). About 200 samples from different water bodies were examined with this method in the Rhine and Ruhr region of North Rhine-Westphalia (Germany). Approximately 94 % of the analysed samples contained measurable amounts of metabolites. For most metabolites, low concentrations ≤0.10 μg/L were determined. Only for three metabolites were the concentrations in ground water significantly higher (up to 20 μg/L). In none of the examined drinking water samples were the health-related indication values (between 1 and 3 μg/L) for non-relevant metabolites exceeded.     

Potential of modified reverse flow injection analysis for continuous monitoring and process control

Summary Modified reverse flow injection analysis is introduced as a novel means for monitoring purposes and online process control. The technique is based on the injection of standard solutions into the continuously flowing sample stream. The transient detector response occurring shortly after the injection reflects the deviation between the analyte concentration of the sample stream and the standard injected. Interpolative calibration and the check of nominal values are two interesting execution modes presented. The beneficial features of the novel approach are discussed and exemplarily demonstrated for practical problems. Experimental conditions are given for the photometric determination of chloride in tap water, phosphate in surface water and the potentiometric determination of fluoride. The respective advantages over common monitoring systems are outlined.

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Einsatzmöglichkeiten der modifizierten Umkehrfließinjektions-Analyse zur kontinuierlichen überwachung und Prozeßsteuerung

     

离子色谱法测定海产品中磷酸盐、焦磷酸盐、偏磷酸盐和总磷

建立了离子色谱法测定海产品中磷酸盐、焦磷酸盐、偏磷酸盐和总磷的分析方法。样品经100 mmol/L NaOH溶液浸提,固相萃取柱去除有机物、阳离子、中和OH~后用于海产品中磷酸盐、焦磷酸盐和偏磷酸盐的测定;样品经干灰化法消化,固相萃取柱净化后用于总磷测定。考察了提取溶液的pH、有机物和共存离子对测定结果的影响。该方法的线性范围为0.3～60 mg/L,检出限为2.1～2.3 mg/kg,相对标准偏差为1.6%～2.6%。海鱼和虾仁样品中目标物的加标回收率为81.8%～100.0%。该方法选择性好,灵敏度高,用于实际样品测定结果令人满意。     

熔融制样–X射线荧光光谱法同时测定铀钼矿中主次成分

采用混合熔剂熔融制样,建立了同时测定铀钼矿中U,Mo,SiO_2,Fe_2O_3,Al_2O_3等的X射线荧光光谱法。以Li_2B_4O_7–LiBO_2作为熔融试剂,NH_4NO_3作为样品的氧化剂,样品与熔剂的质量比为1∶10。除使用铀矿石国家标准物质外,主要选取人工混合校准样品及历年实验室比对的铀钼矿校准样品绘制成工作曲线。采用理论系数法校正样品的基体效应,用Br Kα,Zr Kα,U Lα,Ba Lα,Zn Kα谱线扣除相应元素的谱线重叠干扰。该方法各组分测定结果的相对标准偏差均小于2.0%(n=10);用标准物质验证方法的准确度,测定值相对误差在0.00~8.00%之间,与标准值基本吻合。该法应用于生产实验中,可以满足对铀钼矿准确、快速的测量要求。