Investigation of four digestion procedures for multi-element determination of toxic and nutrient elements in legumes by inductively coupled plasma-optical emission spectrometry

A simple and reliable multi-element procedure for determination of essential (Cr, Cu, Fe, Mg, Mn, Zn) and toxic (Al, Cd, Pb) elements in legumes by inductively coupled plasma-optical emission spectrometry (ICP-OES) was developed. In this contribution, four different digestion procedures were thoroughly investigated and accurately evaluated with respect to their affect on the analysis of legumes. These included wet digestion with HNO₃/H₂SO₄ and HNO₃/H₂SO₄/H₂O₂, and dry ashing with Mg(NO₃)₂ and Mg(NO₃)₂/HNO₃. Two calibrations (aqueous standard and standard addition) procedures were studied, and proved that standard addition was preferable for all analytes. ICP-OES operating parameters, such as radio-frequency (RF) incident power, sample uptake flow rate and nebulizer argon gas flow rate were optimized. The precision as repeatability, expressed as relative standard deviation (R.S.D.) for aqueous standard containing 250 μg l⁻¹ of each analyte was in the range1.5-8.0%. The accuracy, expressed as relative error was generally varied in the range of 0.5-10% for all analytes, while the quantification limits were lower than 2.5 μg g⁻¹. Although, acceptable results were obtained from all developed procedures, wet digestion method with HNO₃/H₂SO₄/H₂O₂ is recommended for better recovery. The good agreement between measured and certified concentrations with respect to IAEA-331 and IAEA-359 (CRM's supplied by IAEA, International Atomic Energy Agency) indicates that the developed analytical method is well suited for determination of toxic and nutrient elements in legumes and possibly similar matrices.     

Analytical procedures for the determination of selected major (Al, Ca, Fe, K, Mg, Na, and Ti) and trace (Li, Mn, Sr, and Zn) elements in peat and plant samples using inductively coupled plasma-optical emission spectrometry

A simple, robust and reliable analytical procedure for the determination of Al, Ca, Fe, K, Li, Mg, Mn, Na, Sr, Ti, and Zn in peat and plant materials by inductively coupled plasma-optical emission spectrometry (ICP-OES) was developed. A microwave heated high pressure autoclave was used to digest powdered sample aliquots (approximately 200 mg) with different acid mixtures including nitric acid (HNO₃), tetrafluoroboric acid (HBF₄) and hydrogen peroxide (H₂O₂). The optimized acid mixture for digestion of plant and peat samples consisted of 3 mL HNO₃ and 0.1 mL HBF₄, in addition to H₂O₂ which was sub-boiled into the PTFE digestion tubes during heating of the autoclave. Using HNO₃ alone, recoveries of Al and Ti were too low by 40 and 160%, respectively, because HNO₃ could not fully liberate the analytes of interest from the silicate fraction of the plant and peat matrix. However, for all other elements (such as Mn, Sr, and Zn), the use of HBF₄ was less critical. The accuracy of the analytical procedure developed was evaluated with peat and plant reference materials of different origin and composition. The ICP-OES instrument was optimized using solutions of plant reference materials considering RF power, nebulizer pressure, auxiliary gas flow and rinse time. Scandium was used as an online internal standard (IS) as it provided accurate results and showed less than 3% drift in sensitivity over time which was lower compared to other potential IS such as Rh (20%) and In (6%). The combination of most sensitive and less sensitive wavelengths allowed to obtain low detection limits and highest possible dynamic range. The achieved procedure detection limits ranged from 0.05 μg g⁻¹ (Li) to 15 μg g⁻¹ (Ca) and allowed a precise quantification of all elements. Comparative X-ray fluorescence spectrometric measurements of solid peat and plant samples generally agreed well with results obtained by digestion/ICP-OES. To overcome interferences caused by Na, K, and Li, a solution of 10 μg g⁻¹ CsCl₂ was successfully used as an ionization buffer. The good agreement between the found and certified concentrations in plant and peat reference materials indicates that the developed analytical procedure is well suited for further studies on the fate of major elements in plant and peat matrices.     

ICP-AES法测定红土镍矿中镍、钙、钛、锰、铜、钴、铬、锌与磷的含量

建立了ICP-AES法测定红土镍矿中Ni;Ca;Ti;Mn;Cu;Co;Cr;Zn和P含量的方法。样品用HCl、HNO3溶解,加入HF和HClO4,加热至HClO4烟冒尽,用HCl溶解盐类,过滤,采用ICP-AES法同时测定滤液中Ni、Ca、Mn、Cu、Co、Zn、P;残渣经灼烧、挥硅、K2S2O7熔融、HCl浸取,所得溶液与滤液合并,测定溶液中Cr和Ti含量。方法检出限:P为0.022μg/mL,其它元素在0.0032～0.0085μg/mL之间,方法的精密度(n=7)在1.4%～2.9%之间。分析结果与分光光度法、XRF法和AAS法分析结果的相对误差:Ni、Cu、Co、Cr小于5%,Ti和Mn小于10%,Zn小于15%,Ca和P小于19%。     

Determination of Zn, B, Fe, Mg, Ca, Na and Si in anisette samples by inductively coupled plasma atomic emission spectrometry

A comparative study of several digestion methods of anisette samples has been carried out. Two dry ashing (DA) treatments as well as four wet ashing (WA) procedures using different mixtures of acids were applied for the sample mineralisation before analysis. Once the anisette samples were mineralised, the contents of Zn, B, Fe, Mg, Ca, Na and Si were determined by inductively coupled plasma-atomic emission spectrometry (ICP-AES). Each method has been studied statistically and also attending to their feasibility. After performing the optimisation of the different treatments tested, it was concluded that one wet ashing method employing a HNO₃:H₂O₂ (10:1) mixture was the most suitable. This method was applied to the analysis of anisette samples. Na, Ca, Mg and Si were present in concentrations up to 215 mg l⁻¹ for Na, 11.6 for Mg, 6.2 for Ca and 5.1 for Si. Fe and B concentrations were not higher than 0.12 mg l⁻¹ and lower for Zn.     

The determination of uranium in rocks by inductively coupled plasma-optical emission spectrometry

A method for the determination of uranium in rock samples by emission spectrometry is presented. The rock is dissolved and the uranium content determined by nebulizing the solution into an inductively coupled-plasma optical excitation source. Various spectral lines were investigated. The uranium emission at 378.28 nm -was chosen because of its relative freedom from matrix element spectral interferences. For this emission, a practical detection limit of 0.1 p.p.m. in solution was achieved by optimizing source parameters (power, flow-rate, observation height). Results are compared with those obtained by a number of other techniques.     

ICP-AES法测定铜磁铁矿中铜、锰、铝、钙、镁、钛和磷量

通过样品处理、干扰试验、方法检出限、准确性和精密度试验,确定了最佳实验条件,建立了电感耦合等离子体-原子发射光谱法测定铜磁铁矿中铜、锰、铝、钙、镁、钛和磷含量的方法。试料经盐酸、硝酸、氢氟酸、高氯酸分解,用盐酸溶解盐类,过滤,采用电感耦合等离子体发射光谱法同时测定滤液中铜、锰、铝、钙、镁、钛和磷量。方法检出限：锰、钛和磷小于0.00085%,其它元素小于0.0054%,分析结果与分光光度法、XRF法和AAS法分析结果一致,8个实验室对5个水平样品进行协同试验给出了方法的精密度。     

Simultaneous determination of Fe, P, Ca, Mg, Zn, and Cu in whole blood by two-jet plasma atomic emission spectrometry

Availability of many biological samples in ample quantity for biomedical investigations sometimes is very restricted. Therefore, there is the need for the simple techniques allowing the analysis of small amount samples. In the present work the two-jet plasma atomic emission spectrometry techniques for the determination of Fe, P, Ca, Mg, Zn, and Cu in whole blood are proposed. The first technique is developed for direct analysis of freeze-dried blood. The sample preparation consisted in a dilution of blood powder (particle size 20 μm or less) with a spectroscopic buffer (graphite powder containing 15 wt.% NaCl). For the analysis of liquid whole blood, previous carbonization (not ashing) of blood evaporated on graphite powder was applied. Calibration samples based on graphite powder containing 15 wt.% NaCl were used. The validation of the techniques was confirmed by the use of different sample preparation procedures (wet acid digestion and dry carbonization), the analysis of IAEA A-13 reference material (freeze-dried bovine whole blood), and the comparison of the results obtained by the proposed technique with the results of the stripping voltammetry technique. Just 20-50 μL of whole blood is quite enough for all determinations. The proposed techniques were successfully applied for the simultaneous determination of Fe, P, Ca, Mg, Zn, and Cu in whole blood of living experimental rats and mice and human blood.     

A method for Ca, Fe, Ga, Na, Si and Zn determination in alumina by inductively coupled plasma optical emission spectrometry after aluminum precipitation

In this present work a method for the determination of Ca, Fe, Ga, Na, Si and Zn in alumina (Al₂O₃) by inductively coupled plasma optical emission spectrometry (ICP OES) with axial viewing is presented. Preliminary studies revealed intense aluminum spectral interference over the majority of elements and reaction between aluminum and quartz to form aluminosilicate, reducing drastically the lifetime of the torch. To overcome these problems alumina samples (250 mg) were dissolved with 5 mL HCl + 1.5 mL H₂SO₄ + 1.5 mL H₂O in a microwave oven. After complete dissolution the volume was completed to 20 mL and aluminum was precipitated as Al(OH)₃ with NH₃ (by bubbling NH₃ into the solution up to a pH ~ 8, for 10 min). The use of internal standards (Fe/Be, Ga/Dy, Zn/In and Na/Sc) was essential to obtain precise and accurate results. The reliability of the proposed method was checked by analysis of alumina certified reference material (Alumina Reduction Grade-699, NIST). The found concentrations (0.037% w w⁻¹ CaO, 0.013% w w⁻¹ Fe₂O₃, 0.012% w w⁻¹ Ga₂O₃, 0.49% w w⁻¹ Na₂O, 0.014% w w⁻¹ SiO₂ and 0.013% w w⁻¹ ZnO) presented no statistical differences compared to the certified values at a 95% confidence level.     

电感耦合等离子体发射光谱法同时测定奶粉中钙铜铁钾镁锰钠锌和磷

通过优化试验确定仪器的最佳工作参数,微波加热硝酸消解样品,采用电感耦合等离子体发射光谱法同时测定奶粉中钙、铜、铁、钾、镁、锰、钠、锌和磷9种元素的含量。分析了4种奶粉样品,所得结果与国标方法的结果一致。方法回收率在96.5%-111%之间。     

Chemical vapour generation of transition metal volatile species for analytical purposes: determination of Zn by inductively coupled plasma-optical emission spectrometry

Volatile species of Zn were generated by merging acidified aqueous samples and sodium tetrahydroborate(III) solution in a continuous flow system. The gaseous analyte was subsequently introduced via a stream of Ar carrier into the inlet tube of the plasma torch. Inductively coupled plasma optical emission spectrometry (ICP-OES) was used for detection. The operating conditions (chemical and physical parameters) and the concentrations of different inorganic (hydrochloric, nitric) and organic acids (acetic, citric, oxalic, tartaric) were evaluated for the efficient generation of Zn vapour. A detection limit (3sigma(blank)) of 4.6 ng mL(-1) was achieved. The precision (RSD) of the determination was 6.9% at a level of 250 ng mL(-1) and 4.7% for 1000 ng mL(-1) (n = 10). The efficiency of the generation process was estimated to be close to 50% in HCl. The possible interferent effect of transition metals (Cd, Co, Cu, Cr, Fe, Mn, Ni), hydride forming elements (As, Ge, Pb, Sb, Se) and Hg on Zn signal was examined. The method was validated by the determination of Zn in a certified reference material (CRM), NIST 1643d trace elements in water.     

Application of ultrasound-assisted acid leaching procedures for major and trace elements determination in edible seaweed by inductively coupled plasma-optical emission spectrometry

A new method using diluted reagents (nitric and hydrochloric acids and oxygen peroxide) and ultrasound energy to assist metals acid leaching with from edible seaweed was optimized. The method uses a first sonication at high temperature with hydrochloric acid as a previous stage to an ultrasound-assisted acid leaching with 7 ml of an acid solution containing nitric acid, hydrochloric acid and hydrogen peroxide at concentrations of 3.7, 3.0 and 3.0 M, respectively. Optimum conditions for the first sonication step were ultrasound energy at 17 kHz, sonication temperature at 65 °C, an acid volume of 2 ml, an hydrochloric acid concentration of 6.0 M and a sonication time of 10 min. It has been found that the first sonication stage at high temperature with hydrochloric acid is necessary to obtain quantitative recoveries for As, Ba, Fe and V. Otherwise quantitative recoveries were reached for the other elements investigated (Ca, K, Na, Mg, Cd, Cr, Cu, Mn, Ni, Pb and Zn). The repeatability of the ultrasound-assisted acid leaching method was around 10% for all elements. Adequate limit of detection and limit of quantification were reached by using inductively coupled plasma-optical emission spectrometry (ICP-OES) for measurements. The method resulted accurate after analysing several seaweed certified reference materials (IAEA-140/TM, NIES-03 and NIES-09). The method was finally applied to the multi-element determination in edible seaweed samples.     

Determination of Al, Ba, Ca, Cu, Fe, K, Mg, Mn, Na, Sr and Zn in red wine samples by inductively coupled plasma optical emission spectroscopy: Evaluation of preliminary sample treatments

A comparative study of sample treatment for removing the organic matter (mainly alcohol) to analyse red wine samples for metal content (Al, Ba, Ca, Cu, Fe, K, Mg, Mn, Na, Sr and Zn) from ICP-OES has been carried out. Thus, three procedures have been assayed before metal analysis: Dry ashing (DA), wet ashing (WA) and the removal of alcohol by evaporation (AR). The obtained results showed that the three methods lead to unbiased recoveries close to 100%. However, the uncertainty of AR method was about twice of the remainder ones. From practical considerations, the DA procedure was considered more suitable for determining metal elements in wine samples by ICP-OES.     

等离子体发射光谱法测定矿山水样中硫酸盐的研究

水质中硫酸盐的测定方法很多,但对于成分复杂且盐分很高的矿山水样,传统方法操作繁琐且不环保,本文建立了等离子体发射光谱法测定矿山水样中硫酸盐的方法,样品采用硝酸和盐酸进行加热消解后既可去除硫化物,降低水质的黏度,又可实现多元素同时测定。该方法检出限为0.03mg/L,相对标准偏差为0.1～0.4%(n=6),方法具有方便,快捷,检出限低,精密度、准确度高且线性范围广的优点。     

Multi-element determination in raft mussels by fast microwave-assisted acid leaching and inductively coupled plasma-optical emission spectrometry

Studies on the application of a short microwave irradiation cycle and the use of diluted acids to extract trace elements from raft mussel samples were developed. Multi-element determinations (Al, Ba, Cd, Cr, Cu, Fe, Mn, Pb, Sn, V and Zn) were carried out by inductively coupled plasma-optical emission spectrometry (ICP-OES). Parameters such as acid/oxidizing reagents (diluted nitric acid, hydrochloric acid and hydrogen peroxide) concentrations, acid/oxidizing solution volume, temperature, ramp time and hold time for the microwave heating were simultaneously studied by using an experimental design approach. The optimum conditions have showed the sample pre-treatment of 10 mussel samples to less than 3.0 min when a microwave power of 600 W and a controlled temperature of 65 °C were used. This time (hold time plus ramp time) is quite shorter than those reported for conventional microwave-assisted acid digestion procedures. Since temperature inside the reactor is not high, the venting time can be shorted to 15 min. In addition, the concentration of acid/oxidizing reagents needed to complete the acid leaching (2.5 M, 3.0 M and 0.5 % (m/v) for nitric acid, hydrochloric acid and hydrogen peroxide, respectively) is lower than the required concentration for a conventional microwave-assisted acid digestion (concentrated acids). The proposed method has showed a good repeatability of the overall method, and relative standard deviations between 11 and 2% were reached for 12 replicate microwave-assisted acid leaching and ICP-OES measurements. The method was finally validated by analyzing TORT-1 and GBW-08571 certified reference materials and it was successfully applied to fast multi-element determinations in several raft mussel samples.     

三种癌的铬、锰、锌、铜、铁、镁、钙含量

为进一步阐明癌组织与宏量、徽量元素的关系．用原子吸收光谱法测定胃癌、大肠癌、乳腺癌组织及其癌旁组织和同体正常组织中铬、锰、锌、铁、镁、铜和钙的含量．试找这些元素在癌、癌旁及其同体正常组织中的分布规律．测定结果；在胃癌组织中锌的含量比癌旁组织、同体正常组织少。铜的含量比正常组织多。其余五种元素的含量在这三个组织之间比较无明显差异；在大肠癌组织中锰、镁的音量比癌旁组织多．其他五种元素的含量在这三个组织之间比较，无明显差异；在乳腺癌组织中铬，锰和铁的含量比正常组织多。锌、镁、钙的含量比同体正常组织和癌旁组织多，铜的含量在这三个组织中比较无明显差异，总之，胃癌、大肠癌及乳腺癌组织及其癌旁组织和同体正常组织中。上述七种元素的音量是不同的。特别是在乳腺癌组织中除铜以外的六种元素的含量都比正常组织多．值得进一步研究．     

Ligandless-ultrasound-assisted emulsification microextraction followed by inductively coupled plasma-optical emission spectrometry for simultaneous determination of heavy metals in water samples

In this study, a simple and efficient method of ligandless-ultrasound-assisted emulsification microextraction (LL-USAEME) followed by inductively coupled plasma-optical emission spectrometry (ICP-OES) has been developed for simultaneous extraction, preconcentration and determination of manganese, cadmium, cobalt and nickel in water samples. In the proposed approach, tetrachloroethylene was selected as extraction solvent. The effect of important experimental factors such as volume of extraction solvent, pH, sonication time, salt concentration, and temperature was investigated by using a fractional factorial design (2^5?1) to identify important factors and their interactions. In the next step, a Box-Behnken design (BBD) was applied for optimisation of significant factors. The obtained optimal conditions were: 30?µL for extraction solvent, 12 for pH, 5?min for sonication time, and 5% w/v for salt concentration. The limits of detections (LODs) for Cd(II), Co(II), Mn(II) and Ni(II) were 0.20, 0.13, 0.21 and 0.28?µg?L^?1, respectively. Relative standard deviations (RSD, C?=?200.0?µg?L^?1, n?=?9) were between 3.4–7.5% and the calibration graphs were linear in the range of 0.25 to 1000.0?µg?L^?1 for Mn, 0.5–1000.0?µg?L^?1 for Co and Ni and 1.0–250.0?µg?L^?1 for Cd. The determination coefficients (R ²) of the calibration curves for the analytes were in the range of 0.993 to 0.999. The proposed method was validated by using two certified reference materials, and also the method was applied successfully for the determination of heavy metals in different real water samples.     

Extraction inductively coupled plasma-optical emission spectrometry (ICP-OES) determination of traces of phosphorus in tungsten

A method for the separation and preconcentration of traces of phosphorus from tungsten was developed. Solid phase extraction of the phosphovanadomolybdate complex performed on a micro-column was applied. Phosphorus was determined by optical emission spectroscopy (OES) with inductively coupled plasma (ICP) excitation. A limit of detection of 0.4 g/g P with respect to the solid phase is obtained. By directly coupling the extraction/elution step to the ICP instrument a detection limit of 0.06 g/g P in W was achieved. Besides, the complexity of spectral evaluation in ICP-OES determinations of traces in spectralline-rich matrices is discussed.Presented in part at the 1989 European Winter Conference on Plasma Spectrochemistry, Reutte, Austria     

Application of multivariate curve resolution-alternating least squares for the determination of boron isotope ratios by inductively coupled plasma-optical emission spectrometry

Multivariate curve resolution-alternating least squares (MCR-ALS) was applied to atomic emission data obtained from inductively coupled plasma-optical emission spectrometry analysis of boron for the quantification of ¹⁰B/¹¹B ratios. The determination of isotopic composition of boron is based on the isotopic shift of ¹⁰B and ¹¹B in the emission line of 208.957 nm. After recording of the emission spectra in the range of 208.940–208.970 nm, evaluation of isotopic composition of boron containing samples was performed with MCR-ALS algorithm. MCR-ALS was able to resolve the emission spectra of ¹⁰B and ¹¹B mixtures. The performance of the proposed methods was tested by determination of ¹⁰B/¹¹B ratios in synthetic mixtures and also water samples.     

Design of a compact, aluminum, tungsten-coil electrothermal vaporization device for inductively coupled plasma-optical emission spectrometry

A new compact, aluminum electrothermal vaporization cell was constructed for inductively coupled plasma-optical emission spectrometry analysis. This cell is compact enough to fit within the space occupied by the spray chamber and fits directly to the quartz torch without extraneous tubing through the use of a simple Compression fitting. Sample volumes as low as 10 μL were analyzed with an automated control program for efficient vaporization. Twelve elements were analyzed utilizing a time resolved acquisition method so that real-time data could be generated over a period of 10 s with an average improvement factor of 14 for elements over a wavelength range of 193–445 nm.