Elimination of interferences from Cu, Pb, Ag, Au, Pt, Pd and Se in the determination of mercury by CVAAS using sodium tetrahydroborate(III) reduction in copper concentrates

The determination of mercury in the presence of Cu, Pb, Ag, Au, Pt, Pd, Se and As by cold vapor atomic absorption spectrometry was studied. Sodium tetrahydroborate(III) was used as a reducing agent. All the elements examined except arsenic exhibited strong interferences. A solution of 1,10-phenanthroline and thiosemicarbazide in 1.5% HCl solution was used as a masking agent. A highly effective reduction of interference by Cu, Ag, Au, Pt, Pd and Se was achieved. The results obtained were applied to the determination of mercury in a copper concentrate.     

Determination of trace elements in automotive fuels by filter furnace atomic absorption spectrometry

The determination of Cd, Cr, Cu, Pb and Ni was performed in gasoline and diesel fuel samples by electrothermal atomic absorption spectrometry using the Transverse Heated Filter Atomizer (THFA). Thermal conditions were experimentally defined for the investigated elements. The elements were analyzed without addition of chemical modifiers, using organometallic standards for the calibration. Forty-microliter samples were injected into the THFA. Gasoline samples were analyzed directly, while diesel fuel samples were diluted 1:4 with n-heptane. The following characteristic masses were obtained: 0.8 pg Cd, 6.4 pg Cr, 12 pg Cu, 17 pg Pb and 27 pg Ni. The limits of determination for gasoline samples were 0.13 μg/kg Cd, 0.4 μg/kg Cr, 0.9 μg/kg Cu, 1.5 μg/kg Pb and 2.5 μg/kg Ni. The corresponding limit of determination for diesel fuel samples was approximately four times higher for all elements. The element recovery was performed using the addition of organometallic compounds to gasoline and diesel fuel samples and was between 85 and 105% for all elements investigated.     

Determination of trace elements in coal and coal fly ash by joint-use of ICP-AES and atomic absorption spectrometry

Microwave-acid digestion (MW-AD) followed by inductively coupled plasma-atomic emission spectrometry (ICP-AES), graphite furnace atomic absorption spectrometry (GFAAS), and hydride generation atomic absorption spectrometry (HGAAS) were examined for the determination of various elements in coal and coal fly ash (CFA). Eight certified reference materials (four coal samples and four CFA samples) were tested. The 10 elements (As, Be, Cd, Co, Cr, Mn, Ni, Pb, Sb, and Se), which are described in the Clean Air Act Amendments (CAAA), were especially considered. For coal, the HF-free MW-AD followed by ICP-AES was successful in the determination of various elements except for As, Be, Cd, Sb, and Se. These elements (except for Sb) were well-determined by use of GFAAS (Be and Cd) and HGAAS (As and Se). For CFA, the addition of HF in the digestion acid mixture was needed for the determination of elements, except for As, Sb, and Se, for which the HF-free MW-AD was applicable. The use of GFAAS (Be and Cd) or HGAAS (Sb and Se) resulted in the successful determination of the elements for which ICP-AES did not work well. The protocol for the determination of the 10 elements in coal and CFA by MW-AD followed by the joint-use of ICP-AES, GFAAS, and HGAAS was established.     

The determination of trace metals in mineral waters : Part I. Atomic Absorption Spectrometric Determination of Cd,Co, Cr,Cu, Ni and Pb by Electrothermal Atomization After Concentration by Co-precipitation

Procedures based on flameless atomic absorption spectrometry are described for the determination of Cd, Co, Cr, Cu, Ni and Pb in mineral waters. Because of matrix effects and the inadequate detection limits for direct determinations, the metals are separated from the macrocomponents by precipitation of their tetramethylenedithiocarbamates with iron(III) as collector, or by co-precipitation on Fe(OH)₃. The detection limits are 0.005, 0.3, 0.08. 0.10, 2 and 0.10 μg l^- for Cd, Co, Cr, Cu, Ni and Pb, respectively, and are satisfactory for the determination of these elements in mineral waters. The precision is 2–7%.     

The decomposition of oils and fats in a stream of oxygen for the determination of trace elements

For the determination of Al, Cr, Mn, Fe, Cu, Zn, Se, Cd, Hg and Pb at μg g^-1 and ng g^-1 levels in oils and fats by electrothermal atomic absorption spectrometry (a.a.s.), the sample is burnt in a stream of pure oxygen in a special combustion apparatus (Trace-O-Mat). Volatile elements are condensed on a cold finger cooled with liquid nitrogen. After combustion the trace elements are dissolved off the cooled areas and from the sample holder by refluxing with 2 ml of high-purity nitric acid (65%). Recoveries were tested on reference materials by electrothermal a.a.s. and were found to be ? 95%.     

Determination of heavy metals and their speciation in waters and bottom sediments of water reservoirs using inductively coupled plasma atomic emission spectrometry and electrothermal atomic absorption spectrometry

The use of inductively coupled plasma atomic emission spectrometry in combination with electrothermal atomic absorption spectrometry and autoclave sample preparation essentially improved performance characteristics of the determination of heavy metals and simplified analytical procedures for determining their speciation. Inductively coupled plasma atomic emission spectrometry can give information about the concentrations of a wide range of elements in water and bottom deposits at a level of MPC and, thus, is useful for revealing sources of pollution of water reservoirs. More sensitive electrothermal atomic absorption spectrometry was used for determining background concentrations of Pb, Cd, Co, Ni, Cu, Cr, Mo, and As and assessing the speciation of Pb, Cd, Co, Cu, and Zn in waters and bottom sediments. Based on the results of analyses of surface, bottom, and void waters; bottom sediments and their step-by-step extracts; and KMC and DEAE cellulose adsorbents containing charge-separated heavy metals, the ecological status of Kuibyshev, Ivan’kovo, and Rybinsk water reservoirs was assessed.     

热解齐化-原子吸收光谱法测定红土镍矿中汞含量

经过条件试验,建立了热解齐化-原子吸收光谱法直接测定红土镍矿中汞含量的方法。样品中汞含量在57～1752μg／kg,重复测定的相对标准偏差（RSD）在1．6％～5．3％（n=11）,回收率在92．79％～94．77％,与冷原子吸收光谱法的方法间相对偏差为5．18％～11．93％。方法准确、快速、样品用量少、无试剂污染,适合于批量样品的测试,有应用和推广价值。     

Comparative study of heavy metal and trace element accumulation in edible tissues of farmed and wild rainbow trout (Oncorhynchus mykiss) using ICP-OES technique

The objective of this research was to determine the differences between farmed and wild rainbow trout in terms of heavy metal and trace element accumulation in edible tissues. The samples were analyzed for As, Ba, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Se, Sr and Zn by inductively coupled plasma-optical emission spectrometry (ICP-OES); and for Hg by cold vapor atomic absorption spectrometry (CVAAS). The results were expressed as μg/g of dry weight. With the exception of Ba and Sr, liver had significantly higher heavy metal and trace element concentrations compared to the muscle in farmed or wild fish. Higher levels of Ba, Cr, Fe, Mn and Zn, as well as lower levels of Cu and Sr were found in tissues of wild rainbow trout compared to its farmed relative. Levels of Cd in 41.6% of farmed fish samples and 45.8% of wild fish samples exceeded the European Commission regulation. Regarding the Pb, concentrations in 50% of farmed fish samples and 62.5% of wild ones were above the European Commission limit. However, levels of Hg and As in all of the examined samples were lower than the legislated limits. The differences in heavy metal and trace element accumulation observed between farmed and wild fish were probably related to the differences in their environmental conditions and dietary element concentrations.     

New sorbents and indicator powders for preconcentration and determination of trace metals in liquid samples

Two approaches to immobilize complex-forming analytical reagents (PAN, PAR, Xylenol orange, Brombenzothiazo, Crystal violet, Cadion, and Sulfochlorophenolazorhodanine) for the preparation of new sorbents and indicator powders are suggested: on-line coating of reversed-phase silica gel by reagents or doping of porous sol-gel silica with reagents. The retention of Ag, Cd, Cu(II), Co(II), Fe(III), Mn(II), Ni, Pb, and Zn on the sorbents developed was investigated. Quantitative sorption and desorption conditions were optimized. Procedures for the determination of Cd, Cu(II), Fe(III), Pb, and Zn with flame atomic absorption, spectrophotometric, and diffusion scattering spectrometric detection were elaborated. Detection limits for Cd, Cu(II), Fe(III), Pb, and Zn were 3 μg/L, 6 μg/L, 5 μg/L, 40 μg/L, and 1 μg/L, respectively. The procedures were used for the analysis of various real samples, e.g., natural and waste waters, and food.     

火焰原子吸收法测定树头发的微量元素

使用灰化法处理样品,火焰原子吸收光谱法测定了药用真菌树头发中的Zn、Se、Fe、Cu、Ag、Cd的含量。结果表明,除Cd未检出外,树头发中的微量元素含量Zn、Se、Fe、Cu、Ag分别为12．835、2．376、35．256、1．029、0．078μg／g,各元素含量由高到低顺序为：Fe、Zn、Se、Cu、Ag,加标回收率为96．3％-106．7％。     

藏药材铁棒锤的微量元素含量分析

目的研究藏药材铁棒锤的微量元素含量。方法使用电感耦合等离子体质谱仪(ICPMS)测定藏药材铁棒锤药材中As、Hg、Pb、Cd含量,使用原子吸收光谱仪(火焰法、石墨炉法)测定药材中Zn、Mn、Cr、Fe、Ca、K、Cu元素的含量并进行分析。结果铁棒锤中有害元素As、Hg、Pb、Cd含量较低,Cu、Fe等有益元素含量较高。结论藏药材铁棒锤有丰富的微量元素,具有较高的开发利用价值。     

Spectrophotometric determination of lithium with Quinizarin in drugs and serum

An endemic peripheral vascular disorder resulting in gangrene of the lower extremities, especially of the feet, is called 'Blackfoot disease (BFD)'. Clinically, the symptoms and signs of Blackfoot disease are similar to those of Buerger's disease. In this study, the objective is to examine the amount of arsenic, mercury, zinc, lead, and selenium in urine samples from BFD patients. After pre-treatment with acids, the samples were digested by means of a microwave oven. The determination of arsenic mercury, zinc, lead and selenium were by hydride atomic absorption spectrometry (HAAS), cold vapor atomic absorption spectrometry (CVAAS), flame atomic absorption spectrometry (FAAS), graphite furnace absorption spectrometry (GFAAS), respectively. The results indicated that urinary arsenic, mercury and lead of the BFD patients were significantly higher than those of the normal controls, while urinary zinc and selenium were significantly lower than those of the normal controls. The possibility that these elements are involved in the etiology of diseases is discussed.     

A sequential injection cold-vapor atomic absorption method for the determination of total mercury

A sequential injection (SI) method for the determination of mercury via cold vapor atomic absorption spectrophotometry is presented. The method differs from flow injection (FI) cold vapor methods for the determination of mercury because of the simplicity of the system required for the method: one pump, one valve, a gas-liquid separator, and an atomic absorption spectrophotometer equipped with a quartz cell. Under optimal conditions, the method has the following figures of merit: a linear ¶calibration range of 1.0 to 20 μg L^–1; a detection limit of 0.46 μg L^–1; and a precision of 0.90% RSD (8 μg L^–1). The procedure allows for a sampling rate of one injection per 80 s (excluding sample pretreatment). Results from the determination of mercury in water and fish specimens are also presented. The figures of merit of the method are compared to two other SI methods for the determination of mercury.     

Determination of trace metals in natural waters at nanogram per liter levesls by electrothermal atomic absorption spectrometry after extraction with sodium diethyldithiocarbamate

The determination of trace metals (Cd, Co, Cu, Fe, Ni and Pb) at concentrations found in fresh and sea waters is described. The metals are extracted as diethyldithiocarbamates from 500-ml samples into carbon tetrachloride, the extracts are evaporated to dryness and the residues are mineralized with 0.1 ml of concentrated nitric acid. This solution is used for graphite-furnace atomic absorption spectrometry after appropriate dilution. The detection limits are 10 pg Cd, 150 pg Co, 125 pg Cu, 100 pg Fe, 250 pg Ni and 100 pg Pb. The extraction/mineralization method is almost free from interferences, e.g., from trace elements at 500-fold and Na, K, Ca and Mg at million-fold amounts. The procedure is successfully applied to the determination of the above metals in deionized water, and river and sea waters.     

An Instrumental Correction for the Determination of Mercury in Biological and Sediment Samples Using Cold Vapor Atomic Absorption Spectrophotometry

Low recovery rate and inconsistent measurements were found in the determination of mercury by method of cold vapor atomic absorption spectrophotometry using the hydride formation system (Hitachi HFS-2, Hitachi Ltd., Tokyo). To overcome this problem of insufficient reaction time we developed a simple T-joint device attaching to the commercial HFS-2 system for the determination of mercury in various biological tissues and sediment samples. The T-joint device was designed to combine sample and reductant injection which increased the reaction time of the sample allowing a complete formation of mercury vapor and speeding up the analysis process in comparison to the traditional cold vapor atomic absorption spectrometric method. Recoveries of mercury were in the range 95% - 100%. The corrected procedure gave precise and accurate readings with several certified reference materials: NIES No. 2 from the Japan Environment Agency; IAEA-356 from the International Atomic Energy Association, and DOLT-2, DORM-2, TORT-2, PACS-1 and MESS-2 from the National Research Council of Canada. Simple acid digestion methods were developed based on the sample Hg level and the nature of the sample. The sample detection limits were 0.0125 μg g⁻¹ fresh weight and 0.0625 μg g⁻¹ dry weight for biological samples, and as low as 0.0125 μg g⁻¹ dry weight for sediment samples. These analytical protocols we established met the general requirements in environmental research and monitoring of mercury pollution.     

青海枸杞子中微量元素含量的测定

测定了青海枸杞子中锌、铜、锰、铅、砷、铁、硒等微量元素的含量。结果表明,青海枸杞子中含锌18.65μg/g,铜15.62μg/g,锰6.24μg/g,铅1.03μg/g,砷0.24μg/g,铁19.68μg/g,硒2.15μg/g,人体必需微量元素含量丰富,是枸杞具有极为重要的保健、防病、治病功能的重要原因之一。     

Determination of cadmium and lead at low levels by using preconcentration at fullerene coupled to thermospray flame furnace atomic absorption spectrometry

A new and sensitive method for Cd and Pb determinations, based on the coupling of thermospray flame furnace atomic absorption spectrometry and a preconcentrator system, was developed. The procedure comprised the chelating of Cd and Pb with ammonium pyrrolidinedithiocarbamate with posterior adsorption of the chelates on a mixture (40 mg) of C₆₀ and C₇₀ at a flow rate of 2.0 ml min⁻¹. These chelates were eluted from the adsorbent by passing a continuous flow of ethanol (80% v/v) at 0.9 ml min⁻¹ to a nickel tube placed in an air/acetylene flame. After sample introduction into the tube by using a ceramic capillary (0.5 mm i.d.), the analytical signals were registered as peak height. Under these conditions, improvement factors in detectability of 675 and 200 were obtained for Cd and Pb, respectively, when compared to conventional flame atomic absorption spectrometry. Spiked samples (mineral and tap waters) and drinking water containing natural concentrations of Cd were employed for evaluating accuracy by comparing the results obtained from the proposed methodology with those using electrothermal atomic absorption spectrometry. In addition, certified reference materials (rye grass, CRM 281 and pig kidney, CRM 186) were also adopted for the accuracy tests. Due to the good linearity ranges for Cd (0.5–5.0 μg l⁻¹) and Pb (10–250 μg l⁻¹), samples with different concentrations could be analyzed. Detection limits of 0.1 and 2.4 μg l⁻¹ were obtained for Cd and Pb, respectively, and RSD values <4.5% were observed (n=10). Finally, a sample throughput of 24 determinations per hour was possible.     

Graphite furnace analysis—getting easier and achieving more?

The impact of microwave digestion, hot injection of solutions and chemical modification on the analysis of biological samples by electrothermal atomic absorption spectrometry (AAS) has been assessed. The stabilizing effects of palladium and ruthenium modifiers were compared. Although ruthenium has a higher atom appearance temperature, palladium was the more useful modifier when samples other than water were analysed. When 2 μg of palladium (as PdCl₂) was preconditioned in hydrogen at 500°C, volatile elements were retained at char temperatures up to 1000–1100°C. This allowed similar atomizer programmes to be used for Cd, Cu, Fe, Mn and Pb and accurate determination of these analytes in solutions of reference materials was achieved aqueous standards. Rapid drying of the solutions by hot injection at 120°C reduced the programme time to just over 1 min. A combination of microwave digestion, hot injection of 40% (w/v) HNO₃ solutions and Pd modification produced a rapid and sensitive method for determination of Cd and Pb at sub-μg g^?1 levels in vegetable and protein foodstuffs. Palladium modification also proved useful in simultaneous multi-element determination by continuum source AAS. The picogram detection limits obtained for Cr, Mn and Pb were similar to line source AAS values recorded with the same compromise programme. Accurate determination of Cd, Cr, Cu, Mn, Mo and Pb in NIST SRM 1566 Oyster Tissue indicated the potential of continuum source AAS for multi-element determinations. The advantages of palladium modifications were also illustrated for furnace atomic non-thermal excitation spectrometry (FANES) with a hollow-cathode discharge. The maximum char temperatures of Ag, Ga, Hg, Pb, Sb and Se were increased by 300–600°C in the presence of 1 μg of Pd, although the detection limits were a factor of two poorer.     

Amalgamation performances of gold-coated quartz wool,alumina, silica,sand and carbon fiber for the determination of inorganic mercury in waters by cold vapor atomic absorption spectrometry

Different gold-coated sorbents for amalgamation were applied for the determination of inorganic mercury in waters using a home-made cold vapor generation unit coupled to atomic absorption spectrometry. Among the gold-coated materials investigated (quartz wool, alumina, silica, sand and carbon fiber) quartz wool was found to give the most efficient results in terms of sorption and release. Analytical performance of the system without and with amalgamation was investigated and it was found that when amalgamation was applied, the linearity and slope of the calibration plots were independent on the sample volume for 1.0, 5.0 and 10.0 mL. Method validation was realized through the analysis of a sample of spring water spiked with 1.0 μg/L inorganic mercury and the spike recoveries were found to be 95 ± 1, 91 ± 3, and 99 ± 5% for 1.0, 5.0, and 10.0 mL, respectively. The results demonstrated that the methodology can be applied to these types of samples directly or after amalgamation, depending on the mercury concentration.     

Determination of trace Pb(Ⅱ), Cd(Ⅱ) and Zn(Ⅱ) using differential pulse stripping voltammetry without Hg modification

In this work,we reported a simultaneous determination approach for Pb(II),Cd(II)and Zn(II)atμg L 1concentration levels using differential pulse stripping voltammetry on a bismuth film electrode(BiFE).The BiFE could be prepared in situ when the sample solution contained a suitable amount of Bi(NO)3,and its analytical performance was evaluated for the simultaneous determination of Pb(II),Cd(II)and Zn(II)in solutions.The determination limits were found to be 0.19μg L 1for Zn(II),and0.28μg L 1for Pb(II)and Cd(II),with a preconcentration time of 300 s.The BiFE approach was successfully applied to determine Pb(II),Cd(II)and Zn(II)in tea leaf and infusion samples,and the results were in agreement with those obtained using an atomic absorption spectrometry approach.Without Hg usage,the in situ preparation for BiFE supplied a green and acceptability sensitive method for the determination of the heavy metal ions.