Routine analysis of ultra pure water by ICP-MS in the low- and sub-ng/L level

The chemical analysis with inductively coupled plasma-mass spectrometry (ICP-MS) can help to examine the purity of ultra pure water (UPW) down to 10 part per trillion (ng/L) and lower. For a proper determination of a high number of samples per week the analysis must be divided into two parts: the routine analysis and the reference water analysis. The routine analysis is done by direct measurement of the ultra pure water samples. Applying a standard addition method under particular clean conditions, the reference water analysis leads to the definition of the accurate zero. A quick evaluation scheme is also presented for the reference water analysis. The method is tested for its fitness for application by examining LOD (for relevant element < 2 ng/L), reproducibility and linearity of calibration. The ICP-MS was optimized according to the methodology of G. Taguchi to improve reproducibility and LOD. Received: 16 June 1999 / Revised: 2 August 1999 / Accepted: 6 August 1999     

Trace analysis of bromate in drinking waters by means of on-line coupling IC-ICP-MS

The on-line-coupling of ion chromatography (IC) and inductively coupled plasma mass spectrometry (ICP-MS) is a powerful tool for the determination of bromate in drinking waters. The use of a high-capacity and high-performance anion-exchanger combined with an NH₄NO₃-based elution system allows the determination of bromate in almost every water sample without any sample pretreatment. The method detection limits in the water samples investigated are 50 to 65 ng/L or 44 to 58 pg bromate, respectively. Considering sensivity as well as imprecision (5% at 500 ng/L bromate) and short analysis times (8 to 15 min per sample including sample uptake), the described IC-ICP-MS coupling is well suited for precise routine analyses of bromate in drinking waters at the sub μg/L level.     

停留-反相流动注射阻抑光度法测定超痕量铋(Ⅲ)

基于在B-R缓冲溶液介质中,Bi(Ⅲ)对H2O2氧化孔雀石绿(MG)褪色反应的显著阻抑作用,建立了一种停留-反相流动注射阻抑光度法测定超痕量Bi(Ⅲ)的新分析方法,该方法的线性范围为0.001～0.54 ng/L,检出限为9.9×10-4ng/L,相关系数为0.9992。对0.001 ng/LBi(Ⅲ)平行测定11次的标准偏差为1.3%,进样频率为20.9次/h。该方法可直接用于人发和水中的超痕量Bi(Ⅲ)的测定,回收率为96.0%～102.0%。     

Determination of Trace Arsenic and Selenium in Water Samples by Inductively-Coupled-Plasma Mass Spectrometry

Utilisation of a miniature anion-exchanger preconcentration column of Dowex 1-X8 to increase the sensitivity for As and Se determinations by inductively-coupled-plasma mass spectrometry (ICP-MS) is described. The ion signal was enhanced were 15 fold for As and 20 fold for Se. The multielement detection limits were 2 ppt (ng/L) and 33 ppt for As and Se, respectively. This flow injection ICP-MS method was applied to the determination of trace levels of arsenic and selenium in riverine reference material SLRS-2 and spring water samples.     

Development and statistical validation of a quantitative method for the determination of steroid hormones in environmental water by column liquid chromatography/tandem mass spectrometry

This paper presents an analytical method applied to the determination of 3 natural steroid hormones, estrone, 17 beta-estradiol, and 16 alpha-hydroxyestrone, and the contraceptive estrogen, 17 alpha-ethynylestradiol, at the sub-ng/L level in water samples [surface water and wastewater treatment plant (WWTP) samples]. The solid-phase extraction conditions were optimized using C18 cartridges. Identification and quantification were performed using a column liquid chromatographic/tandem mass spectrometric system with electrospray ionization in the negative mode. Before analyzing steroids in complex matrixes, statistical tools permitted a fine validation of the analytical method, and performance was evaluated for spring water in terms of recovery, specificity, trueness, repeatability, and intralaboratory reproducibility. The results showed the accuracy of the method, and limits of detection (LOD) ranged between 0.02 and 0.21 ng/L. The determination of steroids in WWTP effluents, which contain high levels of organic matter, required an additional purification step on silica cartridges. The high efficiency of the purification was proved with LOD < 0.3 ng/L from 200 mL sample. Specificity of the entire analytical procedure was shown by repeatable recoveries at low and high levels of the calibration range.     

Rapid liquid chromatography-tandem mass spectrometry method for the determination of a broad mixture of pharmaceuticals in surface water

Herein, a new method for the detection of 13 different pharmaceuticals and one metabolite in surface water at low ng/L levels is described. The method utilizes ultra performance liquid chromatography-tandem mass spectrometry and a solid-phase extraction sample preparation. Mean method detection limits were low (4.10 ng/L) and overall solid-phase extraction recovery and reproducibility was adequate (mean recovery, 77.9%; mean RSD, 7.3%). The method allows for quick run times and minimal solvent use as compared with other previously reported high performance liquid chromatography-based methods. Application of this method for the detection of pharmaceuticals in Tennessee River surface water determined that caffeine, sulfamethoxazole, and carbamazepine were frequently detected (100% of samples). Trimethoprim was moderately detected (30% of samples); acetaminophen, atorvastatin, and lovastatin were infrequently detected (10% of samples); and ciprofloxacin, diltiazem, fluoxetine, levofloxacin, norfluoxetine, ranitidine, and sertraline were not detected. This study reports the first detection of lovastatin in surface water.     

Analysis of estrogenic contaminants in river water using liquid chromatography coupled to ion trap based mass spectrometry

A precise and reliable method, using liquid chromatography combined with ion trap based mass spectrometry, for the determination of three endogenous estrogens, namely, estrone, estradiol, and estriol, and two synthetic estrogens, ethinyl estradiol and diethylstilbestrol, in environmental water samples was developed. Optimization of the parameter settings of the ion source and mass analyzer as well as evaluation of solvent composition were carried out by continuous introduction of standards through a syringe pump. In negative ion mode the electrospray ionization source gave acceptable results. The optimum solvent used consisted of water/acetonitrile, with no volatile bases or buffers added. A simple, off-line, manual solid-phase extraction method was developed for sample preparation of environmental water samples. Recoveries were over 86% for all compounds. The method was validated and found to be linear, selective, and robust. For analysis of a 50-mL sample, the limit of detection (LOD) ranged from 3.2 to 10.6 ng/L for all compounds, and the limit of quantitation (LOQ) from 10.6 to 35.0 ng/L. Within-day (n = 5) and total (n = 5) reproducibility were investigated at three different concentration levels and ranged from 6.2 to 9.5% and 9.4 to 12.1%, respectively. Finally, the method was applied to real-world samples.     

Speciation analysis of mercury in seawater from the lagoon of Venice by on-line pre-concentration HPLC-ICP-MS

A method based on the coupling of HPLC with ICP-MS with an on-line pre-concentration micro-column has been developed for the analysis of inorganic and methyl mercury in the dissolved phase of natural waters. This method allows the rapid pre-concentration and matrix removal of interferences in complex matrices such as seawater with minimal sampling handling. Detection limits of 0.07 ng L(-1) for inorganic mercury and 0.02 ng L(-1) for methyl mercury have been achieved allowing the determination of inorganic mercury and methyl mercury in filtered seawater from the Venice lagoon. Good accuracy and reproducibility was demonstrated by the repeat analysis of the certified reference material BCR-579 coastal seawater. The developed HPLC separation was shown to be also suitable for the determination of methyl mercury in extracts of the particulate phase.     

Up‐and‐down shaker‐assisted ionic liquid‐based dispersive liquid—liquid microextraction of benzophenone‐type ultraviolet filters

Sun protection is an important part of our lives. UV filters are widely used to absorb solar radiation in sunscreens. However, excess UV filters constitute persistent groups of organic micropollutants present in the environment. An environmentally friendly ionic‐liquid‐based up‐and‐down shaker‐assisted dispersive liquid?liquid microextraction device combined with ultra‐performance liquid chromatography coupled with photodiode‐array detection has been developed to preconcentrate three UV filters (benzophenone, 2‐hydroxy‐4‐methoxybenzophenone, 2,2′‐dihydroxy‐4‐methoxybenzophenone) from field water samples. In this method, the optimal conditions for the proposed extraction method were: 40 μL [C₈MIM][PF₆] as extraction solvent and 200 μL methanol as disperser solvent were used to extract the UV filters. After up‐and‐down shaking for 3 min, the aqueous solution was centrifuged at 5000 rpm speed, then using microtube to collect the settled extraction solvent and using ultra‐performance liquid chromatography for further analysis. Quantification results indicated that the linear range was 2–1000 ng/mL. The LOD of this method was in the range 0.2–1.3 ng/mL with r² ≥ 0.9993. The relative recovery in studies of different types of field water samples was in the range 92–120%, and the RSD was 2.3–7.1%. The proposed method was also applied to the analysis of field samples.     

甲基丙烯酸酯毛细管整体柱分离微囊藻毒素的研究

以甲基丙烯酸丁酯为单体,乙二醇二甲基丙烯酸酯为交联剂,在致孔剂存在的条件下原位聚合制备了甲基丙烯酸丁酯毛细管整体柱(150 μm i.d.)。实验中优化了用此整体柱分离3种微囊藻毒素(MC-LR,-YR和-RR)的色谱条件(流动相种类、缓冲溶液浓度、pH、流动相流速),建立了微囊藻毒素的整体柱毛细管液相色谱分离方法,该法可以在9 min之内实现3种微囊藻毒素的基线分离。将该方法应用于实际水样中微囊藻毒素的分析,成功实现了培养水样和巢湖水样中微囊藻毒素的快速分离,两种样品中均检测到MC-LR。结果表明,所制备的甲基丙烯酸酯毛细管整体柱具有良好的重现性、渗透性,在微囊藻毒素的常规检测中具有很好的应用前景。     

Determination of uranium in tap water by ICP-MS

A fast and accurate procedure has been developed for the determination of uranium at microg L(-1) level in tap and mineral water. The method is based on the direct introduction of samples, without any chemical pre-treatment, into an inductively coupled plasma mass spectrometer (ICP-MS). Uranium was determined at the mass number 238 using Rh as internal standard. The method provides a limit of detection of 2 ng L(-1) and a good repeatability with relative standard deviation values (RSD) about 3% for five independent analyses of samples containing 73 microg L(-1) of uranium. Recovery percentage values found for the determination of uranium in spiked natural samples varied between 91% and 106%. Results obtained are comparable with those found by radiochemical methods for natural samples and of the same order for the certified content of a reference material, thus indicating the accuracy of the ICP-MS procedure without the need of using isotope dilution. A series of mineral and tap waters from different parts of Spain and Morocco were analysed.     

柱前衍生化-HPLC法测定恩施3种富硒蔬菜中硒氨基酸

采用HPLC与ICP-MS间隙联用的方法,以柱前衍生化-HPLC法进行定性定量分析,使用ICP-MS鉴定,建立一种富硒蔬菜中硒氨基酸的分离检测方法。结果表明:所测定的硒代氨基酸在其线性范围内呈现良好的线性关系(R2>0.999)。该方法中硒代蛋氨酸和硒代胱氨酸的检出限分别为0.204 mg/L和0.680 mg/L,加标回收率分别为97.4%和94.0%,RSD分别为2.1%和0.69%。检测恩施富硒蔬菜样品,白菜、萝卜叶和苋菜含有硒代蛋氨酸和硒代胱氨酸。此方法可用于富硒蔬菜中硒代氨基酸的含量检测。     

在线固相萃取-超高效液相色谱-三重四极杆质谱法测定水源水和饮用水中107种典型农药及代谢产物

为进行我国水体中农药风险监测,针对水体中农药种类多、浓度低的特点,建立了在线固相萃取-超高效液相色谱-串联质谱法快速筛查和检测水源水及饮用水中107种典型农药及代谢产物(有机磷类、有机氮类、有机杂环类、氨基甲酸酯类、酰胺类、苯甲酰脲类、新烟碱类等)的方法。样品经0.22 μm孔径亲水性聚四氟乙烯滤膜过滤后,通过自动进样器取5 mL样品注入在线固相萃取系统,经X Bridge C₁₈在线固相萃取柱吸附后用纯水淋洗,以乙腈和0.1%甲酸水溶液为流动相对在线固相萃取柱梯度洗脱后再经ACQUITY HSS T₃色谱柱分离,采用电喷雾离子源正离子及负离子模式分析检测,外标法定量。以水源水及饮用水作为基质,对其准确度和精密度进行方法学验证,结果表明:107种农药及代谢产物在不同范围内线性关系良好(r²>0.995),方法检出限(LOD, S/N=3)为0.03~1.5 ng/L,定量限(LOQ, S/N=10)为0.1~5.0 ng/L。将目标分析物在1、20、50 ng/L水平下加标,水源水和饮用水中的加标回收率分别为60.6%~119.8%和61.2%~119.0%,相对标准偏差(RSD, n=6)分别为0.3%~18.6%和0.4%~17.1%。用该方法测定水源水和饮用水中的农药残留,结果显示,酰胺类、三嗪类除草剂、三唑类杀菌剂与烟碱类、氨基甲酸酯类杀虫剂有较高的检出率,其中水源水中检出含量为0.1~97.1 ng/L,饮用水中检出含量为0.1~93.6 ng/L。该方法适用于水源水和饮用水中107种典型农药及代谢产物的痕量分析测定,有效提高了水体中农药类物质的检测效率,实际应用价值较高。     

Flow injection determination of methamidophos using online photo-oxidation and fluorimetric detection

A photochemical method for the determination of methamidophos using a flow injection system is proposed. The method is based on the rapid decomposition of methamidophos in the presence of peroxydisulphate upon irradiation with UV light. The phosphate generated in the photochemical process is made to react with molybdate in dilute nitric acid to form phosphomolybdic acid, which oxidises thiamine to thiochrome. The thiochrome can then be fluorimetrically monitored at 440 nm with excitation at 375 nm. The method shows a linear range between 14 and 1400 ng ml(-1) with a limit of detection of 1.7 ng ml(-1). The repeatability was 0.3% expressed as relative standard deviation (n=10) and the reproducibility, studied on five different days, was +/-3%. The sample throughput was 70 injections per h. The reliability of the method for routine analysis of water and vegetable samples is demonstrated.     

Evaluation of semiquantitative analysis mode in ICP-MS

Semiquantitative analysis mode in inductively coupled plasma mass spectrometry (ICP-MS) has been popularly used for fast screening purposes. Although the benefit of it has been studied by many researchers, its performance of application in real-world routine analyses has not been reported.

In this study, we evaluated the reliability of semiquantitative analysis mode through inter-laboratory comparison using two different ICP-MS systems with one multi-element calibration standard. The suitability of semiquantitative analysis mode in routine analysis laboratory was demonstrated by evaluating its application in different laboratories and in real production laboratory practices. Twenty one elements were measured, namely, Be, B, Al, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, As, Sr, Mo, Ag, Cd, Sn, Sb, Ba, Tl, and Pb in various fresh water reference samples. Good results concerning accuracy (relative percentage error within 10%) and reproducibility (relative standard deviation lower than 5%) were obtained in more than 90% analyzed samples at concentrations equal to or greater than 10 times the detection limit (DL). Semiquantitative analysis mode also enabled the determination of elements that are not present in the calibration standard. The results demonstrated the potential of semiquantitative analysis mode as a reliable approach in routine laboratory determination of simple matrices, where high throughput and cost-effectiveness are desired, as well as in emergency situations where speed of analysis is critical and quite often limited sample information is available.     

Reduction of polyatomic interferences in biological material using dynamic reaction cell ICP-MS

An analytical method is described for the routine quantification of five elements (As, Cr, Fe, Ni, and Se) in plants and animal feedstuffs using dynamic reaction cell inductively coupled plasma mass spectrometry (ICP-DRC-MS) after microwave digestion. Methane (for Cr, Fe, Ni, and Se) and oxygen (for As) were used as reaction gases to reduce polyatomic interferences. Optimization of the gas flow rate and the quadrupole dynamic bandpass tuning parameter (RPq) was carried out for the method. Detection limits (LOD) were in the range of 0.03–0.65 µg L^? 1 and were significantly lower compared to the standard mode without DRC. The trueness of the method was tested using three reference materials from Round robin tests. Results were well in accordance with the certified values. Furthermore, DRC data were examined by analyzing the same samples using sector field ICP-MS (SF-ICP-MS) and an ICP-MS equipped with collision cell technology (ICP-CCT-MS). The data obtained were in the confidence range of the reference material, too. The investigated method was applied for the analysis of grass and corn silage samples.     

Highly Sensitive Differential Pulse Voltammetric Determination of Cd,Zn and Pb Ions in Water Samples Using Stable Carbon‐Based Mercury Thin‐Film Electrode

A new carbon‐based mercury thin‐film electrode consisting of screen‐printed carbon on a low temperature co‐fired ceramic substrate was made. Ex‐situ mercury deposition in a potassium thiocyanate solution was used. This approach an electrode with high long‐term stability (>500 measurement cycles) and reproducibility (≤2 %) for sensitive determination of ultra trace heavy metals, using differential pulse anodic stripping voltammetry. The detection limits were 0.25, 0.08 and 5.5 ng mL^?1 for Cd(II), Pb(II), and Zn(II), respectively. The method was applied to the determination of the analytes in water, wastewater, lake water, and certified reference material samples with satisfactory results.     

Method for the determination of thorium and uranium in urine by ICP-MS

ICP-MS (inductively coupled plasma mass spectrometry) is shown as a very sensitive method for quantitative determination of Th and U concentration and excretion analysis in urine without any sample pretreatment. The current standard method for incorporation monitoring applies alpha-spectrometry, a very tedious and time consuming technique. ICP-MS offers an attractive alternative for monitoring of thorium and uranium body burdens in occupationally exposed subjects and also larger groups of the general population. A limit of determination of 0.5 ng/L in aqueous solutions and 1 ng/L in urine samples for both elements was achieved, with a precision of about ± 10% in the concentration range of appr. 10 ng/L. Due to the lack of a suitable reference material, the accuracy of the method was tested by comparing some of the results with those obtained by -spectrometry, especially for U. There was a sufficient agreement on both results.     

Synthesis of ractopamine molecularly imprinted membrane and its application in the rapid determination of three β‐agonists in porcine urine samples

A novel molecularly imprinted membrane (MIM) with ractopamine (RAC) as the template and the hydrophilic PVDF membrane as the support was synthesized for the selective absorption of RAC and its structure analogues. The absorption behavior and selectivity of the MIM were studied. The experimental results showed that the MIM had the good selectivity to three β‐agonists including RAC, RIT, and formoterol (FOM) than that of nonimprinted membrane. The adsorption capacity for three compounds was above 1.88 μg/cm² of per membrane. Based on the clean‐up and enrichment of porcine urine samples with the MIM, a sensitive determination method of three β‐agonists in porcine urine samples by using MIM followed ultra performance chromatography coupled MS/MS detection was developed. The LOD and LOQ for RAC, RIT, and FOM were below 0.006 and 0.02 ng/mL, respectively. The mean recoveries, repeatability, and reproducibility of three compounds in porcine urine samples varied from 67.9 to 86.3%, from 3.3 to 10.8%, and from 5.3 to 8.5%, respectively. The presented method was applied to test 50 real porcine urine samples. It was demonstrated to be more sensitive and robust for the determination of RAC, RIT, and FOM in porcine urine.     

Determination of bromate in drinking water by ultraperformance liquid chromatography-tandem mass spectrometry

Bromate is a byproduct formed as a result of disinfection of bromide-containing source water with ozone or hypochlorite. The International Agency for Research on Cancer has recognized bromate as a possible human carcinogen, thus it is essential to determine in drinking water. Present work highlights a development of sensitive and fast analytical method for bromate determination in drinking water by using ultraperformance liquid chromatography-tandem mass spectrometry. The quality parameters of the developed method were established, obtaining very low limit of detection (0.01 ng/mL), repeatability and reproducibility have been found to be less than 3% in terms of relative standard deviation when analyzing a bromate standard at 0.05 μg/mL with 0.4 min analysis time. Developed method was applied for the analysis of metropolitan and bottled water from Saudi Arabia; 22 samples have been analyzed. Bromate was detected in the metropolitan water samples (from desalinization source) at concentrations ranging between 3.43 and 75.04 ng/mL and in the bottled water samples at concentrations ranging between 2.07 and 21.90 ng/mL. Moreover, in comparison to established analytical methods such as liquid chromatography-tandem mass spectrometry, the proposed method was found to be very sensitive, selective and rapid for the routine analysis of bromate at low level in drinking water.