Solution cathode glow discharge induced vapor generation of mercury and its application to mercury speciation by high performance liquid chromatography-atomic fluorescence spectrometry

A novel solution cathode glow discharge (SCGD) induced vapor generation was developed as interface to on-line couple high-performance liquid chromatography (HPLC) with atomic fluorescence spectrometry (AFS) for the speciation of inorganic mercury (Hg(2+)), methyl-mercury (MeHg) and ethyl-mercury (EtHg). The decomposition of organic mercury species and the reduction of Hg(2+) could be completed in one step with this proposed SCGD induced vapor generation system. The vapor generation is extremely rapid and therefore is easy to couple with flow injection (FI) and HPLC. Compared with the conventional HPLC-CV-AFS hyphenated systems, the proposed HPLC-SCGD-AFS system is very simple in operation and eliminates auxiliary redox reagents. Parameters influencing mercury determination were optimized, such as concentration of formic acid, discharge current and argon flow rate. The method detection limits for HPLC-SCGD-AFS system were 0.67 μg L(-1) for Hg(2+), 0.55 μg L(-1) for MeHg and 1.19 μg L(-1) for EtHg, respectively. The developed method was validated by determination of certified reference material (GBW 10029, tuna fish) and was further applied for the determination of mercury in biological samples.     

Determination of Organic and Inorganic Mercury Species as Emetine Dithiocarbamate Complexes by High-Performance Liquid Chromatography with Electrogenerated Tris(2,2′-bipyridine)ruthenium(III) Chemiluminescence Detection

A sensitive method for simultaneous determination of organic and inorganic mercury species has been developed and is presented in this study. The method is based on complex formation of mercury species with the emetine dithiocarbamate (emetine-CS₂) ligand, HPLC separation, and tris(2,2′-bipyridine)ruthenium(III) chemiluminescence detection. The complexation reactions of the mercury species and emetine-CS₂ ligand occurred instantaneously upon the addition of emetine-CS₂ solution to the solution containing the mercury species. The complete separation of these complexes was achieved using an ODS column with 20 mM NaH₂PO₄-acetonitrile (52:48, v/v) containing 30 mM NaClO₄ as an ion-pair reagent. The calibration graphs of these complexes were linear in the range from 1–100 µg/L. The detection limits were 0.27 µg/L, 0.33 µg/L, 0.39 µg/L, and 0.17 µg/L for methylmercury, ethylmercury, phenylmercury, and the mercury ion, respectively, at a signal-to-noise ratio of 3. The developed technique was validated by analyzing certified reference materials, CRM7402-a (cod fish, NMIJ) and CE464 (tuna fish, ERM), in combination with sonication-assisted acid leaching and liquid-liquid extraction. The emetine-CS₂ ligand has been used for extraction, separation, and detection of mercury species. The results determined using the proposed method were in good agreement with the values of the certified reference materials. The MeHg⁺ and EtHg⁺ recoveries for the spiked samples were found to be almost 100%.     

Method to reduce the memory effect of mercury in the analysis of fish tissue using inductively coupled plasma mass spectrometry

The routine determination of mercury (Hg) by inductively coupled plasma mass spectrometry (ICP-MS) is affected by a pronounced memory effect in the sample introduction system. This results in long washout times for the analyte, which affects the accuracy and reliability of the analytical procedure. By using a combination of flow injection sample introduction and a sulfur-containing compound in the carrier solution, it was possible to decrease the memory effect of mercury to that for the internal standard (rhodium). The carrier solution contained 2-mercaptoethanol (2-ME) and the developed method was evaluated using three different fish tissue certified reference materials: CRM 464 (BCR, Brussels); DORM-1; and DORM-2 (NRC, Canada). The samples were mineralized using a combination of concentrated nitric acid and hydrogen peroxide and heating in a closed microwave oven. The developed flow injection ICP-MS procedure gave values for total mercury in all three CRM materials in agreement with the certified concentration range. Cold vapour atomic fluorescence spectrometry (CV-AFS) confirmed the results from the developed method. The developed flow injection method had a detection limit (defined as three times the standard deviation of the blank concentration) for mercury of 5.1 μg l⁻¹.     

Speciation of Chromium in Water Samples by Cloud Point Extraction Combined with Low Temperature Electrothermal Vaporization ICP‐OES

Abstract

A new method based on cloud point extraction (CPE) separation and electrothermal vaporization inductively coupled plasma optical emission spectrometry (ETV‐ICP‐OES) detection was proposed for the determination of chromium species. Thenoyltrifluoracetone (TTA) was used as both an extractant for CPE of Cr(III) and a chemical modifier for ETV‐ICP‐OES determination. When the system temperature is higher than the cloud point temperature (CPT) of the selected surfactant, Triton X‐114, the complex of Cr(III) with TTA could enter the surfactant‐rich phase, whereas the Cr(VI) remained in aqueous solutions. Thus, an in situ separation of Cr(III) and Cr(VI) could be realized. The concentrated analyte was introduced into ETV‐ICP‐OES for determination of Cr(III) after proper disposal. Cr(VI) is reduced to Cr(III) prior to determining total Cr, and its assay is based on substracting of Cr(III) from total chromium. The main factors affecting cloud point extraction and the vaporization behavior of the analyte were investigated in detail. Under the optimized conditions, the limit of detection (LOD) for Cr(III) was 0.22 µg/L by preconcentration of a 10 mL sample solution, and the relative standard deviation (RSD) was 3.8% (C_Cr(III)=0.5 µg/mL, n=5). The proposed method was applied to the speciation of chromium in different water samples. In order to verify the accuracy of the method, a certified reference water sample was analyzed, and the results obtained were in good agreement with certified values.     

Analytical Characterization of a Solution Cathode Glow Discharge with an Interference Filter Wheel for Spectral Discrimination

Solution cathode glow discharge–atomic emission spectrometry (SCGD–AES) has attracted increasing attention in recent years in water and environmental analysis. In this article, the traditional spectrometer was replaced by an interference filter wheel for spectral discrimination using SCGD–AES. The aforementioned interference filters selected the spectral lines of Na, K, Ca, Li, Sr, Rb, and Cs. These spectral signals were transferred to weak currents using a photomultiplier tube and amplified by a picoammeter. The solution flow rate, discharge current and slit width were optimized individually. The analytical performance of SCGD coupled with an interference filter wheel was studied for atomic emission (SCGD–IFW–AES). The results show that the limits of detection for Na, K, Ca, Li, Sr, Rb, and Cs were 0.16, 0.36, 107, 0.53, 330, 1.93, and 13.58?µg/L, respectively. The relative standard deviations of the spectral intensities for the seven elements were 0.58, 0.94, 0.69, 0.70, 0.63, 0.67, and 0.65%, which indicated that the system operated stably. Matrix effect experiments were performed to study the effect of different concentrations of Na on the spectral intensities of K and Ca. Based on these measurements, the concentration of K in physiological saline was determined to be 0.534?mg/L by SCGD–IFW–AES.     

Ultrasensitive determination of mercury by solution anode glow discharge atomic emission spectrometry coupled with hydride generation

An innovative method for the ultrasensitive detection of mercury by solution anode glow discharge atomic emission spectroscopy (SAGD-AES) coupled with hydride generation (HG) was first investigated. In this method, the mercury vapor generated by the HG was transmitted to the SAGD through the miniature hollow tungsten tube for excitation and detected by a miniaturized spectrograph. A thorough parametric evaluation of the HG and SAGD system was performed, including the type and concentration of carrier acid, He flow rate, concentrations of NaBH₄, discharge current and discharge gap. Under optimal operating conditions, the detection limit for Hg²⁺ achieved 0.03 μg/L, with a relative standard deviation of 1.1% at the Hg²⁺ concentration of 5 μg/L. Moreover, the correlation coefficient of the calibration curve was 0.9996 in the range between 0.1 and 10 μg/L. The accuracy and practicability of HG-SAGD-AES were verified by measuring GBW09101b (human hair), GBW10029 (fish), soil and rice samples. The results showed good agreement with the certified values and values from direct mercury analyzer (DMA).     

Hg(II)-imprinted thiol-functionalized mesoporous sorbent micro-column preconcentration of trace mercury and determination by inductively coupled plasma optical emission spectrometry

Hg(II)-imprinting thiol-functionalized mesoporous sorbent was prepared by a sol–gel method and characterized by X-ray diffraction (XRD), FT-IR spectroscopy and nitrogen gas adsorption–desorption. The static adsorption capacity of the Hg(II)-imprinted and non-imprinted sorbent was 78.5 and 26.6 mg g⁻¹, respectively. The breakthrough capacity was 4.46 mg g⁻¹, and the relative selectivity coefficient for Hg(II) in the presence of Cd and Pb was 3.3 and 3.9, respectively. A new method using a micro-column packed with Hg(II)-imprinting thiol-functionalized mesoporous sorbent has been developed for preconcentration of trace mercury prior to its determination by inductively coupled plasma optical emission spectrometry (ICP-OES). The effects of pH, sample flow rate and volume, elution solution and interfering ions on the recovery of the analyte have been investigated. The limit of detection was 0.39 ng ml⁻¹ with a concentration factor of 150 times. The developed method has been applied to the determination of trace mercury in some biological and environmental samples with satisfactory results. The accuracy was assessed through recovery experiments and analysis of certified reference material.     

A pre-concentration procedure employing a new imprinted polymer for the determination of copper in water

This work describes the development by response surface methodology (RSM) of a procedure for copper determination by inductively coupled plasma optical emission spectrometry (ICP OES) in water samples after extraction by copper imprinted polymer. Results of the two-level full factorial design (2⁴) based on an analysis of variance demonstrated that only the solution pH; amount of polymer and adsorption time were statistically significant. Optimal conditions for the extraction of copper samples were obtained by using Box-Behnken design. Solution pH; amount of polymer and adsorption time were regarded as factors in the optimisation study. The working conditions were 4.6, 0.03?g and 3.5?h, for solution pH, amount of polymer; and adsorption time, respectively. Under the optimised experimental conditions, the detection limit of the proposed method followed by ICP OES was found to be 0.8?µg?L^?1. The relative standard deviation (RSD) was found to less than 0.81%. The pre-concentration factor was 22.5. The accuracy of the optimised procedure was evaluated by analysis of certified reference material. The method was applied to the determination of copper in water samples.     

Mercury Speciation in Fish by High-Performance Liquid Chromatography (HPLC) and Post-Column Ultraviolet (UV)-Photochemical Vapor Generation (PVG): Comparison of Conventional Line-Source and High-Resolution Continuum Source (HR-CS) Atomic Absorption Spectrometry (AAS)

An ultraviolet-photochemical generator (UV-PVG) capable of post-column on-line transformation of both organic and inorganic mercury species to cold vapor (Hg⁰) with subsequent detection by quartz tube-atomic absorption spectrometry (QT-AAS) was developed. Mercury(II), methylmercury(I), ethylmercury(I), and phenylmercury(I) were successfully detected after separation by reversed-phase high-performance liquid chromatography (RP-HPLC). Two types of AAS detectors were compared. The first was a commonly used line-source instrument while the second was a high-resolution continuum source (HR-CS) AAS. The latter provided better limits of detection: 0.47?µg?L^?1 for Hg(II), 0.84?µg?L^?1 for methylmercury(I), 0.80?µg?L^?1 for ethylmercury(I), and 2.0?µg?L^?1 for phenylmercury(I). The repeatability at 30?μg?L^?1 was 3.6%, 4.1%, 6.2%, and 4.5% for these species (n?=?10). These figures of merit were comparable with those reported for more sensitive atomic fluorescence spectrometry. Nine sample extraction procedures were investigated. Extraction by tetramethylammonium hydroxide and HCl at 75?°C was selected as the only method compatible with the proposed separation and detection steps providing high extraction efficiency and no changes in mercury speciation. The applicability of the proposed high-performance liquid chromatography–ultraviolet-photochemical vapor generation–quartz tube-atomic absorption spectrometry method was demonstrated using fish samples and certified reference materials (CRM) DOLT-4 (dogfish liver) and ERM-CE464 (tuna fish). The results were comparable to those obtained by a reference method based on L-cysteine extraction and high-performance liquid chromatography–inductively coupled plasma-mass spectrometry (HPLC–ICP-MS) determination.     

碱熔-电感耦合等离子体发射光谱法测定锡矿石中锡

本文采用过氧化钠碱熔消解样品,电感耦合等离子体发射光谱( ICP-AES)法,对锡矿石中锡含量进行了测定。当样品称样量为0.2g时加入2g过氧化钠就能使样品消解完全。为避免水解对测定结果的影响,样品处理后应尽快进行测定。本方法测定锡的检出限为38.4mg/ kg,12次平行测定的相对标准偏差小于5%,对标准物质的测定结果也令人满意。     

On-line precipitation–dissolution in knotted reactor for thermospray flame furnace AAS for determination of ultratrace cadmium

A simple, environmentally friendly, cost-effective and sensitive method was developed for the determination of trace cadmium in rice and water by using flow injection (FI) on-line precipitation–dissolution in a knotted reactor (KR) as a preconcentration scheme for thermospray flame furnace atomic absorption spectrometry (TS-FF-AAS). The preconcentration was achieved by online merging the sample solution and the precipitating reagent in a KR and subsequently eluting the resultant precipitate of cadmium hydroxide with 1 mol/L HNO₃. The eluant was then introduced into TS-FF-AAS for the determination. A self-assembled FI system was employed to hyphenate the KR system with TS-FF-AAS. Under optimal chemical and instrumental conditions, a limit of detection of 0.04 μg/L and a sensitivity enrichment factor of 34 for cadmium was obtained with a total initial sample volume of 4 mL. The proposed method was applied to the determination of cadmium in certified reference rice and water samples with analytical results in good agreement with their certified values. Real rice samples and real water samples were also determined by the proposed method, with analytical results confirmed by inductively coupled plasma mass spectroscopy (ICP-MS).     

The use of electrothermal vaporization ICP-OES for the determination of trace elements in human hair using slurry sampling and PTFE as modifier

A procedure for the determination of trace elements in human hair has been proposed by electrothermal vaporization inductively coupled plasma optical emission spectrometry (ETV-ICP-OES) with slurry sampling. Slurry was prepared by immersing human hair with conc. HNO₃ and then adding a polytetrafluoroethylene (PTFE) slurry, which was used as a chemical modifier for the improvement of vaporization characteristic of analyte. The slurry was homogenized with an ultrasonic vibrator before the measurement. The vaporization behaviour of the analytes in slurry and solution and the main influence factors for the determination were studied with the addition of PTFE systematically. Detection limits for this method varied from 0.033?µg?g^?1 (Cu) to 3.21?µg?g^?1 (Zn) with the relative standard deviations (RSDs) of 2.8–7.1%. The proposed method was successfully applied for the determination of trace elements (Cu, Mn, Cr, Fe, Zn, Cd and Pb) in human hair with minimum chemical pretreatment and aqueous calibration. The accuracy was checked by comparing the results of this method with those using pneumatic nebulization (PN) ICP-OES after a conventional acid decomposition of the same sample. In addition, the standard reference material of human hair (GBW 07601) was analysed with good agreement between the results from the proposed method and the certified values.     

Elemental Analysis of Phytotherapeutic Products by Inductively Coupled Plasma–Tandem Mass Spectrometry

A procedure for the determination of As, Cd, Cr, Ni, Pb, and V in phytotherapy medicines by inductively coupled plasma–tandem mass spectrometry is reported. The use of tandem mass spectrometry with oxygen into an octopole reaction system at various gas flow rates and the combination of on-mass and mass-shift modes was evaluated. Cadmium, Cr, Ni, and Pb were determined as free atomic ions while As and V were determined as the oxides AsO⁺ and VO⁺ in the same run. Samples were prepared by microwave-assisted digestion with dilute nitric acid and hydrogen peroxide. Two plant-certified reference materials (apple leaves and tomato leaves) were used to check the accuracy. For tandem mass spectrometry with 0.5?mL min^?1 O₂, recoveries in the 85–113% were typically obtained and no statistical differences were observed at the 95% confidence level (t-test) in comparison with the certified values. Using these conditions, the limits of detection for the method were 0.01, 0.0002, 0.008, 0.008, 0.003, and 0.002?µg g^?1 for As, Cd, Cr, Ni, Pb, and V, respectively. The procedure was used for the analysis of four phytotherapic drugs and the determined concentrations were up to 0.168?µg g^?1 As, 0.03?µg g^?1 Cd, 0.82?µg g^?1 Cr, 1.18?µg g^?1 Ni, 0.52?µg g^?1 Pb, and 2.4?µg g^?1 V with average precision values of 8% as the relative standard deviation. The found concentrations were compared with limits proposed in official guidelines and, in most cases, the values were below the maximum limits allowed.     

微波消解-电感耦合等离子体发射光谱法测定土壤中的硫

利用微波消解仪消解土壤样品,采用电感藕合等离子体发射光谱仪测定土壤中硫的含量。以浓王水为消解试剂,对土壤样品进行微波消解,优化了王水用量,考察了微波消解条件、谱线干扰情况和仪器参数对硫灵敏度的影响。硫的质量浓度在0~40 mg/L范围内与光谱强度具有良好的线性关系,线性相关系数为0.9997,硫的检出限为0.053 mg/L。土壤中硫测定结果的相对标准偏差为1.54%~7.84%(n=7)。对六种土壤国家一级标准物质进行了测定,测定结果与推荐值相符,无显著性差异。该方法简便、准确,分析效率高,能够满足日常批量样品分析的要求。     

Facilitating local analysis in northern regions: microwave plasma-atomic emission spectrometry for mercury determination in wild Atlantic salmon

An analytical procedure was developed to quantify mercury concentration in wild Atlantic salmon (Salmo salar) muscle tissue by cold-vapour microwave plasma-atomic emission spectrometry (CV-MP-AES) with microwave-assisted acid digestion. Muscle samples were collected from the Atlantic salmon Food, Social, and Ceremonial fisheries in Lake Melville, Labrador (Canada). Muscle samples were digested with nitric acid and hydrogen peroxide, mercury was stabilised with thiourea, reduced with NaBH₄, and quantified by CV-MP-AES. Analysis of fish protein certified reference material (CRM, DORM-3) by CV-MP-AES was used to assess the accuracy and precision of the procedure. CRM recovery averaged 88% with a relative standard deviation of less than 8%. The limits of detection were as low as 0.22 µg?L^?1 in solution which translate to 0.02 µg·g^?1. Mercury concentrations in salmon muscle tissue quantified by CV-MP-AES were not significantly different from results obtained by cold vapour-atomic fluorescence spectrometry (CV-AFS) from an accredited laboratory. Our results indicated that the CV-MP-AES procedure is appropriate for the quantification of mercury at background levels (range 0.15–0.29 µg?g^?1 dry weight) in wild fish of Labrador.     

Hollow fiber liquid phase microextraction combined with graphite furnace atomic absorption spectrometry for the determination of methylmercury in human hair and sludge samples

Two methods, based on hollow fiber liquid–liquid–liquid (three phase) microextraction (HF-LLLME) and hollow fiber liquid phase (two phase) microextraction (HF-LPME), have been developed and critically compared for the determination of methylmercury content in human hair and sludge by graphite furnace atomic absorption spectrometry (GFAAS). In HF-LPME, methylmercury was extracted into the organic phase (toluene) prior to its determination by GFAAS, while inorganic mercury remained as a free species in the sample solution. In HF-LLLME, methylmercury was first extracted into the organic phase (toluene) and then into the acceptor phase (4% thiourea in 1 mol L^− 1 HCl) prior to its determination by GFAAS, while inorganic mercury remained in the sample solution. The total mercury was determined by inductively coupled plasma-mass spectrometry (ICP-MS), and the levels of inorganic mercury in both HF-LLLME and HF-LPME were obtained by subtracting methylmercury from total mercury. The factors affecting the microextraction of methylmercury, including organic solvent, extraction time, stirring rate and ionic strength, were investigated and the optimal extraction conditions were established for both HF-LLLPME and HF-LPME. With a consumption of 3.0 mL of the sample solution, the enrichment factors were 204 and 55 for HF-LLLPME and HF-LPME, respectively. The limits of detection (LODs) for methylmercury were 0.1 μg L^− 1 and 0.4 μg L^− 1 (as Hg) with precisions (RSDs (%), c = 5 μg L^− 1 (as Hg), n = 5) of 13% and 11% for HF-LLLPME–GFAAS and HF-LPME–GFAAS, respectively. For ICP-MS determination of total mercury, a limit of detection of 39 ng L^− 1 was obtained. Finally, HF-LLLME–GFAAS was applied to the determination of methylmercury content in human hair and sludge, and the recoveries for the spiked samples were in the range of 99–113%. In order to validate the method, HF-LLLME–GFAAS was also applied to the analysis of a certified reference material of NRCC DORM-2 dogfish muscle, and the determined values were in good agreement with the certified values.     

Determination of Arsenic,Cadmium, Cobalt,Chromium, Nickel,and Lead in Cosmetic Face-Powders: Optimization of Extraction and Validation

An analytical method for the quantification of toxic metals in face-powders is presented and discussed. Acid digestion with HNO₃-H₂O₂ or HNO₃-HCl was performed and compared with total digestion by HF. The digestion with HNO₃-H₂O₂ was the most suitable for these purposes. Analyses were performed by inductively coupled plasma atomic emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS), whose performances were compared by analyzing three different certified reference materials. The analysis of five commercial face-powders revealed the presence of all the considered metals in the range 0.06–8.0 µg/g. To simulate the bioaccessibility of metals in physiological conditions, a digestion with a simulated sweat solution was performed. In this case, the analysis of the same face-powder samples provided results below the limit of quantification, suggesting low bioaccessibility of the considered trace elements.     

Preconcentration of total chromium on Dowex 50W-X8 resin loaded with 2-amino-benzenethiol

Application of Dowex 50W-X8 loaded with 2-amino-benzenethiol for preconcentration of total chromium (Cr(VI) and Cr(III)) in water samples and subsequent determination by inductively coupled plasma-atomic emission spectrometry was studied. The reagent 2-amino-benzenethiol loaded onto the resin effectively reduced Cr(VI) to Cr(III) and total chromium (both Cr(VI) and Cr(III)) formed chelate complex with the reagent in the Cr(III) valence state. Experimental parameters such as preconcentration time, solution flow rates, pH, and concentration of the eluent were optimized. The method has been applied for the determination of total chromium in seawater samples in the range of 0.1–200?µg?L^?1. A detection limit of 0.3?µg?L^?1 was achieved, and the relative standard deviation was about 5%.     

Determination of Essential and Toxic Elements in Tropical Fruit by Microwave-Assisted Digestion and Inductively Coupled Plasma–Mass Spectrometry

The concentrations of eight essential (Co, Cr, Cu, Mn, Ni, Se, V, and Zn) and five toxic elements (Al, As, Cd, Hg, and Pb) were determined in 457 samples of commonly consumed fresh tropical fruit including bananas (Musa acuminata), kiwi (Actinidia deliciosa), mangos (Mangifera indica), and pineapple (Ananas comosus) from supermarkets from Seoul, Busan, Gangneung, Daegu, Daejeon, and Gwangju, South Korea. The samples were digested by microwave-assisted combustion using HNO₃ and H₂O₂ and determined by inductively coupled plasma mass spectrometry. The Hg concentrations were evaluated by furnace-gold amalgamation direct mercury analysis. The techniques were validated by linearity, limits of detection and quantification, precision, recovery, and the analysis of a NIST-1570a spinach leaves certified reference material. The concentrations of essential elements varied considerably among the tropical fruit. Overall, the tropical fruit was higher in Mn (0.027–13.2?µg/g) and Zn (0.514–2.20?µg/g), while lower in Co (0.002–0.005?µg/g) and V (0.001–0.002?µg/g). The concentrations (µg/g) of toxic elements were 0.001 (kiwi) to 0.003 (mango) for As and Cd, 0.0004 (pineapple) to 0.002 (banana) for Hg, and 0.005 (kiwi) to 0.013 (mango) for Pb. The calculated values of estimated dietary intake, target hazard quotients and hazard indices were lower than one and the safety limits established by World Health Organization. The tropical fruits were therefore safe and did not pose any threat to consumers.     

Fast and selective magnetic solid phase extraction of trace Cd, Mn and Pb in environmental and biological samples and their determination by ICP-MS

We have immobilized iminodiacetic acid on mesoporous Fe₃O₄@SiO₂ microspheres and used this material for efficient and cost effective method of magnetic solid phase extraction (SPE) of trace levels of Cd, Mn and Pb. The microspheres were characterized by infrared spectroscopy, scanning electron microscopy and transmission electron microscopy. The loaded microspheres can be easily separated from the aqueous sample solution by applying an external magnetic field. The effects of pH, sample volume, concentration and volume of eluent, and of interfering ions were investigated in detail. The method has detection limit of 0.16, 0.26 and 0.26?ng?L^?1 for the ions of Cd, Mn and Pb, respectively, and the relative standard deviations (RSDs, c?=?1???g?L^?1, n?=?7) are 4.8%, 4.6% and 7.4%. The method was successfully applied to the determination of these metals in biological and environmental samples using ICP-MS. Two certified reference materials were analyzed, and the results coincided well with the certified values.