Determination of nickel in biological samples by inductively coupled plasma spectrometry after extraction with 1,5-bis(di-2-pyridylmethylene)thiocarbonohydrazide

Summary An ICP-AES method for the determination of nickel subtraces after extraction of the metal into methyl isobutyl ketone(MIBK) containing 1,5-bis-(di-2-pyridylmethylene)thiocarbonohydrazide is suggested. The complex formed is quite soluble in MIBK, so that the determination of concentrations down to 15 times lower than those by the direct non-extractive method is possible. In addition, the extraction step enhances the selectivity. The described method was applied to the determination of nickel in various biological materials, such as red cabbage, algae, liver, kidney, brain and urine.     

Determination of trace heavy metals in biological samples by inductively-coupled plasma atomic emission spectrometry after extraction with 1,5-bis-(di-2-pyridylmethylene)thiocarbonohydrazide

A sensitive inductively-coupled plasma atomic emission spectrometric sequential method for the determination of trace heavy metals (cadmium, cobalt, copper and nickel) in biological samples after extraction of the metals into isobutyl methyl ketone (IBMK) containing 1,5-bis-(di-2-pyridylmethylene)thiocarbonohydrazide (DPTH) is described. A systematic study was made to determine the optimum conditions for extraction of the metals into IBMK. The complexes formed are quite soluble in IBMK, so much so that this allows the use of aqueous-to-organic phase volume ratios of up to 40 and hence the determination of concentrations down to 40 times lower than those afforded by the direct non-extractive method. The method has been used for the determination of these elements in various biological materials with good results.     

Determination of cadmium in biological samples by inductively coupled plasma atomic emission spectrometry after extraction with 1,5-bis[phenyl-(2-pyridyl)methylene]-thiocarbonohydrazide

A systematic study was made of the optimum conditions for cadmium determination in biological samples by ICP-AES after extraction of the metal into methyl isobutyl ketone containing 1,5-bis[phenyl-(2-pyridyl)methylene]-thiocarbonohydrazide. The maximum volume ratio of aqueous to organic phase was 30 1 for a single-stage extraction of 99–100% of the metal ion. The detection limit was 0.3 ng/ml cadmium, and the calibration was linear from 0.4 to at least 150 ng/ml. No interferences from the elements commonly found in biological materials were observed. A precision of 2.5% (P = 0.05) at the 2 ng/ml level of the metal was achieved. The accuracy of the method was demonstrated by analysis of three standard reference materials, giving concentrations of 1.90 ± 0.43, 27.1 ± 1.4 and 2.63 ± 0.38 /g of cadmium, compared with the certified values of 2.20 ± 0.10, 26.3 ± 2.1, and 2.71 ± 0.15 g/g, respectively.     

Determination of rare earth elements in geological samples by inductively coupled plasma atomic emission spectrometry with flow injection liquid-liquid extraction.

A direct sampling with organic solvent extracts for simultaneous multi-element determination implemented with inductively coupled plasma atomic emission spectrometry (ICP-AES) associated with a flow injection liquid-liquid extraction (FI-LLE) sample preconcentration method was studied. The "robustness" of the plasma discharge with tributyl phosphate (TBP) loading was diagnosed by using the Mg II 279.55 nm and Mg I 285.21 nm lines intensity ratio. A FI-LLE preconcentration system for rare earth elements (REEs)-nitrate-TBP was established by using a laboratory-designed phase separator. For these elements, an average sensitivity enhancement factor of 64 was obtained with respect to ICP-AES sampling with aqueous solutions. The precision of the method was characterized by a relative standard deviation (%RSD) of 1.8 - 5.2%. A throughput of 27 samples per hour can be achieved with an organic solvent consumption of less than 200 microl per determination. Good results were obtained for the analysis of standard reference materials.     

Determination of the ZnGeP2 composition by inductively coupled plasma atomic emission spectrometry

A procedure employing inductively coupled plasma atomic emission spectroscopy has been developed for the precise determination of the composition of Zn_{1 + x}Ge_{1 + x}P_{2 + x} alloys after their autoclave digestion. An optimal composition of the acid mixture has been chosen and the conditions preventing element losses in the digestion process have been found. To minimize the error of the developed procedure, the optimal concentration of Zn, Ge, and P in the analytes was found by calculating the results of analysis as atomic ratios Zn : Ge and P : Ge. The accuracy of the developed procedure was confirmed by the standard addition method and the comparison of the results with the results of an independent method. The relative standard deviation of the determination of atomic ratios was 0. 7–2.0%.     

Determination of total dissolved phosphorus in water samples by axial inductively coupled plasma atomic emission spectrometry

A procedure was developed to determine total dissolved phosphorus in groundwater-like samples using axial ICP-AES. Severe and peculiar matrix effects (strongly positive at lower and leveling off at higher matrix concentrations) in the presence of Na and Ca were observed. To reduce these matrix effects, a double approach was utilized consisting of a so-called minimum matrix in combination with an internal standard (Ga in this case). The ‘minimum matrix’ (small amounts of K, Mg and Na) was only added to the standard solution(s) used for the calibration. The detection limit for the whole procedure was 12 μg/L using the P213 nm line. Residual matrix effects were less than 3% (P213 nm line). Received: 21 February 1997 / Revised: 5 June 1997 / Accepted: 6 June 1997     

Determination of total dissolved phosphorus in water samples by axial inductively coupled plasma atomic emission spectrometry

A procedure was developed to determine total dissolved phosphorus in groundwater-like samples using axial ICP-AES. Severe and peculiar matrix effects (strongly positive at lower and leveling off at higher matrix concentrations) in the presence of Na and Ca were observed. To reduce these matrix effects, a double approach was utilized consisting of a so-called minimum matrix in combination with an internal standard (Ga in this case). The ‘minimum matrix’ (small amounts of K, Mg and Na) was only added to the standard solution(s) used for the calibration. The detection limit for the whole procedure was 12 μg/L using the P213 nm line. Residual matrix effects were less than 3% (P213 nm line). Received: 21 February 1997 / Revised: 5 June 1997 / Accepted: 6 June 1997     

Determination of phosphorus in fertilizers by inductively coupled plasma atomic emission spectrometry

An inductively coupled plasma atomic emission spectrometry (ICP-AES) method was developed for the determination of phosphorus in fertilizers. Total phosphorus, direct extraction available phosphorus (EDTA), and water-soluble phosphorus, reported as phosphorus pentoxide (P205), in 15 Magruder check fertilizers were measured by ICP-AES, and the results were compared with those obtained by the AOAC official method. Five analytical wavelengths of phosphorus, 177.499, 178.287, 213.618, 214.914, and 253.565 nm, were tested for the determination of phosphorus in fertilizers, and their detection limits were obtained. Acid effects of perchloric acid and possible matrix effects of aluminum, calcium, magnesium, potassium, and sodium were negligible for phosphorus determination. Wavelength 213.618 nm was the best analytical wavelength for phosphorus determination by all 3 sample preparation methods for the selected Magruder fertilizers. The results demonstrated that the accuracy and precision of the ICP-AES method were comparable with those of the official methods.     

Determination of cadmium by an improved double chamber electrothermal vaporization inductively coupled plasma atomic emission spectrometry

An improved double chamber electrothermal vaporization (ETV) system was designed. A new inner chamber and its bottom plate made of quartz glass were attached with carrier support gas inlet port for the determination of cadmium by inductively coupled plasma atomic emission spectrometry (ICP-AES). The use of the inner chamber in combination with the plate played important roles to transport the metal vapor efficiently into argon ICP. Ten-μl sample aliquots were dried at 100 °C and subsequently heated at 1000 °C on the tungsten boat furnace. The evolved vapor was swept into the ICP source through PTFE tubing and the inner chamber by a 0.8 l/min H₂ (7%)-Ar carrier gas. The performance parameters of ETV-ICP-AES such as temperature program and gas flow rate were evaluated using cadmium standard solution. Under the optimized experimental conditions, the best attainable detection limit at Cd II 214.438 nm line was 0.2 ng/ml with linear dynamic ranges of 50 to 10,000 ng/ml for cadmium. The instrumental precision expressed as the relative standard deviation (RSD) from ten replicate measurements of 10,000 ng/ml for cadmium by ETV-ICP-AES was 0.85%. The present method has been successfully applied to the determination of cadmium in zinc-base materials.     

Determination of trace amounts of molybdenum in water samples by inductively coupled plasma atomic emission spectrometry after cobalt-dithiocarbamate coprecipitation

Summary A method for the determination of trace amounts of molybdenum in fresh water and seawater samples by sequential ICP-AES with microsampling technique after cobalt-dithiocarbamate coprecipitation was developed. The precipitate was dissolved in 100 l of diluted nitric acid (1:2), and the solution obtained was then introduced into an ICP via a concentric nebulizer. By use of 1.7 ml sample, a preconcentration factor of 17 was achieved. Different factors including integration time, sample volume, pumping rate as well as coprecipitation conditions such as pH of the solution, amounts of reagents, standing time for the precipitate and matrix effects were examined and optimized in detail. Under selected conditions the detection limit of the method for Mo is 0.52 g/l using 1.7 ml sample. The procedure was applied to the analysis of water samples (artificial water and open ocean seawater reference material) with quantitative recovery. The analytical results were in good agreement with the certified value. The method is sensitive, simple, accurate and effective, also in the presence of interfering salts and can be applied to small sample volumes.On leave from the Department of Chemistry, Wuhan University, Wuhan, 430072 China     

Determination of myo-inositol hexakisphosphate (phytate) in urine by inductively coupled plasma atomic emission spectrometry

Myo-inositol hexakisphosphate (phytate) is a substance present in urine with an important role in preventing calcium renal calculi development. In spite of this, the use of urinary phytate levels on stone-formers’ evaluation and treatment is still notably restricted as a consequence of the enormous difficulty to analyze this substance in urine. In this paper, a simple procedure for routinary urinary phytate determination based on phosphorus determination through inductively coupled plasma atomic emission spectrometry is described.The method only requires a previous separation of phytate from other components by column anion exchange chromatography. The working linear range used was 0-2 mg l⁻¹ phosphorus (0-7 mg l⁻¹ phytate). The limit of detection was 64 μg l⁻¹ of phytate and the limit of quantification was 213 μg l⁻¹. The relative standard deviation (R.S.D.) for 1.35 mg l⁻¹ phytate was 2.4%. Different urine samples were analyzed using an alternative analytical methodology based on gas chromatography (GC)/mass detection used for inositol determination (phytate was previously hydrolyzed), resulting both methods comparable using as criterion to assess statistical significance P<0.05.     

Determination of nickel in biological materials after microwave dissolution using inductively coupled plasma atomic emission spectrometry with prior extraction into butan-1-ol.

A sensitive procedure has been developed for the determination of ultratrace amounts of nickel in biological materials by inductively coupled plasma atomic emission spectrometry after extraction of the nickel ion into butan-1-ol by using 1,5-bis(di-2-pyridylmethylene)thiocarbonohydrazide as the extracting reagent. Fast, efficient and complete sample digestion is achieved by an HNO3-HCl poly(tetrafluoroethylene) bomb dissolution technique using microwave heating. Results obtained for eleven certified reference materials agreed with the certified values.     

Determination of lithium in biological samples by inductively coupled plasma mass spectrometry

Lithium was determined in human serum by inductively coupled plasma mass spectrometry. Sample preparation was kept to the minimum: serum samples were diluted and beryllium was added as internal standard. Special attention was given to the choice of the internal standard and to the occurrence of memory effects. To test the accuracy of the method several biological reference materials were analysed, namely a “Second-Generation” Biological Reference Material (Freeze-Dried Human Serum) (University of Ghent), Human Serum SRM 909, Whole Egg Powder SRM 1845 and Mixed Human Diet SRM 1548 (National Institute of Standards and Technology). The results were compared with those obtained by other techniques. For the “second-generation” reference freeze-dried human serum a mean lithium concentration of 15.10 ng g^?1 with a standard deviation of 0.54 ng g^?1 dry weight was found. Analyses on serum samples from healthy individuals yielded lithium concentrations ranging from 0.22 to 0.97 μg l^?1.     

固相萃取-电感耦合等离子体原子发射光谱（ICP-AES）法测定地下水中三种重金属

为拓宽固相萃取技术在生态环境监测领域应用范围,建立了树脂固相萃取前处理ICP-AES法测定地下水中铅、铬、镉含量的方法。经前处理条件优化,硝酸洗脱液浓度5%、缓冲溶液pH 7、洗脱速率10 mL/min及进样体积为500mL条件下,铅、铬、镉等三种重金属回收率均可以达到95%以上。该方法中各目标元素在0.02~20 μg/L范围内线性关系良好,相关系数均大于0.999;铅、铬、镉方法测定下限分别0.56μg/L,0.04μg/L,0.24μg/L满足评价要求;方法精密度RSD值在0.44%~5.49%;加标回收率范围分别在98.55%~101.84%、98.5%~104%、95.5%~105%。经监测井实样测试,铅、铬、镉结果处于《地下水质量标准》（GB/T14848-2017）I类限值范围内。该方法干扰小,易操作,为相关国家标准修订提供参考。     

Determination of aluminum and silicon in biological materials by inductively coupled plasma atomic emission spectrometry with electrothermal vaporization

An atomic emission spectrometric method is described for the determination of trace elements in microvolume samples especially of biological materials. Based upon the arrangement of a commercial electrothermal vaporizer and a 40-MHz inductively coupled plasma, the direct determination of aluminum and silicon in human body fluids such as urine and serum and aluminum in hemodialysis solution is performed. The instrumental system involves vaporizing the sample from a modified graphite electrode followed by atomization and excitation of the vapors in the ICP discharge. Compromise experimental conditions are reported and calibration functions compared. Limits of detection in 5-μl samples were 8 pg Al and 2.5 ng Si, and after preconcentration of Al with a poly(acrylamidoxime) resin, the detection limit was 1 pg Al. Recovery of 5 μg $\text{Si}\text{ml}$ and 10 ng $\text{Al}\text{ml}$ from aqueous and synthetic standards was 80–85% and 96–103%, respectively.     

电感耦合等离子体原子发射光谱法测定钛合金中锆

建立电感耦合等离子体原子发射光谱法(ICP-AES)测定钛合金中锆元素的含量。采用盐酸-氢氟酸-硝酸溶解钛合金样品,选择357.247 nm为锆的分析谱线,通过基体匹配法消除基体钛的干扰,以电感耦合等离子体原子发射光谱法测定钛合金中锆的含量。锆的质量分数在0%~0.4%范围内与光谱强度呈良好的线性关系,相关系数大于0.999,定量下限为0.21%。测定结果的相对标准偏差小于2%(n=11),样品加标回收率为99.0%~102.7%。该方法快速、准确,能够满足实际生产中钛合金样品的测定要求。     

电感耦合等离子体原子发射光谱法测定高温合金中低含量钇

建立电感耦合等离子体原子发射光谱法测定高温合金中低含量钇的方法。采用盐酸、硝酸、氢氟酸溶解样品,在优化的仪器条件下,采用基体匹配法配制系列标准工作溶液,选择分析线为360.073 nm。钇的含量在0.0005%~0.050%范围内与光谱强度具有良好的线性关系,相关系数为0.99999,检出限为0.000003%。该方法测定结果的相对标准偏差不大于6.0%(n=8),加标回收率为90.0%~104.0%。该方法简便、快速、准确,可用于高温合金中低含量钇的测定。     

电感耦合等离子体原子发射光谱（ICP-AES）法测定铁矿石中钒

建立了电感耦合等离子体原子发射光谱(ICP-AES)法测定铁矿石中钒含量的分析方法。采用盐酸、硝酸、氢氟酸、高氯酸分解试样,不溶物残渣碱熔融回收,稀盐酸溶解盐类的方式对样品进行分解。对仪器的主要工作参数和分析谱线进行了选择,讨论了基体和共存元素的干扰,以及溶解酸和熔剂等条件实验,确立了最佳分析条件。按实验方法对铁矿石标准样品和试样中钒量进行测定,测定值与标准值或其它方法的认定值基本一致,相对标准偏差RSD<6.5%。     

Determination of uranium in organic solutions by inductively coupled plasma atomic emission spectrometry

The determination of uranium in organic solutions by inductively coupled plasma atomic emission spectrometry is reported. The conditions for achieving plasma stability were determined as well as the optimum conditions (RF power, observation height and argon flow) of a spectrometer for analysis of U(II) 367.007 nm in three organic solvents, xylene, kerosine and benzene. The effects of RF power and observation height on signal-to-back-ground ratio and the detection limits are considered. Spectral interferences due to CN band are discussed.A part of this work was presented at the Second Karlsruhe International Conference on Analytical Chemistry in Nuclear Technology Karlsruhe, FRG, June 5–9, 1989.