Variations in trace element concentrations in breast milk with stages of lactation

The influence of stages of lactation on the mineral and trace elementconcentrations of breast milk collected from 20 healthy lactating women ina Nigeria population was investigated using instrumental neutron activationanalysis (INAA) and proton induced X-ray emission (PIXE) analysis. The breastmilk samples were divided into colostrum (day 1–5), transitional (day6–13) and mature milk (day 14–28). The result of the study showthat colostrum milk has a significantly higher mean concentration of Ca, Cl,Cu, Fe, Mg, Na and Zn than the transitional and mature milk. Furthermore,the mean concentrations of Fe, Mg, Na and Zn in transitional milk were foundto be significantly higher when compared with the mature milk. It was alsoobserved from the semi-log plot of the concentration of the elements againstdays of lactation that the concentration of all the elements decreased significantlythroughout the lactation period studied with Cu, Fe and Zn concentration showingthe greatest decline, particularly in the early stages of lactation.     

Assessment of the chemical characteristics and sources of airborne particulate matter in Santiago, Chile

Neutron activation analysis (NAA), X-ray fluorescence (XRF), proton induced X-ray emission (PIXE), atomic absorption spectrometry (AAS) and ion chromatography (IC) were used for the chemical characterization of airborne particulate matter in Santiago, Chile. The PM10 mass and elemental concentration were higher in the winter than in the summer collection period. Analytical quality assessment for NAA, XRF, PIXE, AAS and IC was performed on some samples. Correlations were found between the elements Pb–Br, Si–Ca–Fe, As–Cu–S and also between the fine mass and black carbon concentrations, which could be associated with some relevant sources.     

PIXE application for multi-element analysis of marine micro-algae and measurement of the concentration factor of zinc

Marine micro-algae (Nannochloropsis sp., Phaeodactylum sp., etc.) wereobtained from the Pacific Ocean off Iwate Prefecture, Japan, and culturedpurely in nutritive seawater, PES and artificial seawater, ASP7 as a culturesolution. The algae in 5 ml of the culture solution was collected on a polycarbonatefilm (pore size : 1.0 µm) by suction filtration. The algae on the filmwas subjected to PIXE analysis. A 2.9 MeV proton beam bombarded it at 50 nAfor 15 minutes. Induced X-ray was measured by Si(Li) detector. Concentrationsof Na, Mg, Al, Si, P, S, Cl, K, Ca, Cr, Mn, Fe, Cu, Zn and Sr were determinedsimultaneously. PIXE can used for multi-element analysis of a sample below1 mg, so the culture size for algae was 10–250 ml and every apparatuswas small and of low cost. Nannochloropsis sp. was given a different culturesolution (PES) including Zn²⁺ from 0.050 to 1.0 mg/l and incubatedat 22 °C, 2000 lux for 10 hours. Zn in Nannochloropsis sp. increased inproportion to the Zn²⁺ concentration in the culture solution. Theconcentration factor was given as 1600 500 (dry weight base). It was shownthat PIXE was a powerful tool for multi-element analysis of micro organismsand the measurement of bioaccumulation.     

Level of some minor and trace elements in Bangladeshi meat products

An investigation on the level of some minor and trace elements in some varieties of meat (beef, mutton and chicken) consumed in Bangladesh is reported. In this study, protoninduced X-ray emission (PIXE) and radioisotope-induced X-ray fluorescence (XRF) techniques were used for analytical measurements. In PIXE measurements, the samples were exposed to the proton beam in air as 1 mm thick pellets and irradiated with 2.0 MeV protons having the beam intensity of 30 nA for characteristic X-ray excitation, whereas in XRF, the samples were excited for 5000 seconds with a 10 mCi¹⁰⁹Cd annular X-ray source. The elemental concentrations of Ca, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Rb and Sr were determined in the samples by comparison with X-ray yield curves constructed from IAEA and NBS standard reference materials. The significance of the results is dicussed in relation to human health and diseases.This research received financial support from the International Atomic Energy Agency, Vienna, under the research contract RC-4265/RB.     

单波长激发-能量色散X射线荧光光谱法检测蔬菜中多种重金属元素

为实现蔬菜中多种元素的快速检测,利用单波长激发-能量色散X射线荧光光谱仪（MW-EDXRF）,建立了蔬菜中As、Pb、Cd、Cr、Ni、Cu、Zn、Rb、Mn等元素的快速检测方法。对XRF的激发时间、载样量、样品压片等条件进行了优化,结果显示当累积激发时间达到600 s、载样量为2 g、样品压片15 Mpa保持60 s时,可以实现XRF最优检测性能。在最优条件下,As、Pb、Cd、Cr、Ni、Cu、Zn、Rb、Mn的检出限（LOD）分别为0.07 mg/kg、0.07 mg/kg、0.07 mg/kg、0.32 mg/kg、0.32mg/kg、1.2 mg/kg、0.4 mg/kg、0.08 mg/kg、0.3 mg/kg;对菠菜、葱、胡萝卜、豆角、番茄、姜、空心菜、莲藕、芹菜、蒜等蔬菜样品测定11次的相对标准偏差（RSD）在3%~10%,表明方法具有良好的精密度;测定5种蔬菜基体标准物质的回收率在93%~119%,与微波消解电感耦合等离子体质谱法（ICP-MS）测定结果对比的线性回归系数（R2）>0.99（Cu的R2=0.9838）,表明方法具有良好的检测准确度。同时,该仪器仅有不到10 kg,不需要样品消解处理,检测时间在10 min左右,非常适合蔬菜多种重金属的现场快速筛查。     

X-Ray Fluorescence and the In Vivo Evaluation of Fe, Cu and Zn in Skin

We are seeking to extend the capabilities of an in vivo XRF system which was originally designed for the exclusive detection of Fe in skin. Our interest concerns development of a more versatile in vivo XRF diagnostic facility for measurement of Fe and Zn. Elevations of these two elements have been noted to occur in a number of skin disorders and ailments. The XRF system comprises a high-output tungsten anode X-ray tube, the collimated exit beam of which is made to impinge on an appropriate choice of filter. The present study makes use of a beam hardening filter in place of our previous use of a K-edge filter. Operating at 15 kVp, 23 mA, and using a Mo beam hardening filter of 0.2 mm thickness, we have obtained a quasi-monoenergetic output of approximately 13 keV and full-width at tenth maximum (FWTM) of 1.4 keV. Preliminary measurements on simulated skin indicate that we are able to detect Fe, Zn and Cu, at levels of the order of 20-, 10- and 5 g (g skin tissue)^–1, respectively, using monitoring periods of the order of 2000 seconds, and skin entrance doses of less than 16 mSv.     

Determination of lead, cadmium, zinc, copper, and iron in foods by atomic absorption spectrometry after microwave digestion: NMKL Collaborative Study

A method for determination of lead, cadmium, zinc, copper, and iron by atomic absorption spectrometry (AAS) after microwave digestion was subjected to a collaborative study in which 16 laboratories participated [including users of inductively coupled plasma (ICP) and ICP-mass spectrometry (MS)]. The types of samples included in the study were minced fish, wheat bran, milk powder, bovine and pig liver, mushroom, 2 simulated diets, and bovine muscle; the last 4 were certified reference materials. These were analyzed as single (4 samples), double blind (1 sample), or split level (2 samples) samples. Before the collaborative study, a pretrial was conducted in which 4 ready-made solutions and one fish tissue sample were analyzed for Pb and Cu. The reproducibility relative standard deviation (RSDR) values, for results above the detection limit, ranged from 59% at 0.155 mg/kg to 16% at 1.62 mg/kg for Pb, from 28% at 0.0124 mg/kg to 11% at 0.482 mg/kg for Cd, from 9.3% at 35.3 mg/kg to 1.7% at 147 mg/kg for Zn, from 39% at 0.241 mg/kg to 3.0% at 63.4 mg/kg for Cu, and from 17% at 7.4 mg/kg to 5.9% at 303 mg/kg for Fe. The RSDR values agreed well with the norms described by the International Union of Pure and Applied Chemistry. As a complement to the AAS determinations, a number of laboratories analyzed the samples either by ICP or by ICP-MS. The results of these analyses agreed well with the AAS results. On the basis of the results of the collaborative study, the method was adopted Official First Action by AOAC INTERNATIONAL.     

Interlaboratory simultaneous multielement analysis of aerosol samples from Šumava mountains

The samples of the solid aerosol were taken in umava mountains (SFR/FRG frontier) to be analyzed by PIXE or XRF methods in the frame work of air pollution import investigation. To evaluate differences in the results and to minimize discontinuities in the time series, some analyses of the same samples were done by both methods. The peak areas of Al, Si, S, K, Ca, Ti, Cr, Mn, Fe, Cu and Zn were compared to establish the degree of correlation for separate elements. On the basis of the comparison, the multiplicative factors were determined to estimate the XRF peak areas from the PIXE ones. Relative element concentrations and other data were derived from both determined and estimated peak areas and taken into account in the preliminary stage of research.     

Sedimentation pattern and sediments bioavailability in a wastewater discharging area by sequential metal analysis

Atomic absorption spectrometry was applied to investigate sedimentation pattern and sediments bioavailable phase (BAP) at 41 sites of a wastewater discharging area. The position of sampling sites was confirmed by the aid of a global positioning system (GPS). Contaminants discharged from a large wastewater plant are dispersed to the inner bay and the coastal line rather than the outer bay and the center waterway. The fractional composition of sediment Zn in the discharging area accounted for the presence of exchangeable 239 mg/kg (35.1%)>reducible 163 mg/kg (24.0%)>carbonate 149 mg/kg (22.0%)>residual 98 mg/kg (14.4%)>organic 31 mg/kg (4.6%) in sediment layers of 0–2 cm. However, the order was changed in layers of 15–20 cm as residual>reducible>organic>carbonate>exchangeable. The most abundant fraction of sediment Cu and Fe was organic Cu and residual Fe, respectively. The content of BAP in sediments are quite different with respect to metal species and sediment layer analyzed. It is obvious that sequential metal analysis is a useful tool in understanding dispersion of sediments and sedimentation patterns.     

Daily dietary intake of trace elements of radiological and nutritional importance by the adult Indian population

The concentrations of eleven trace elements: Ca, Co, Cr, Cs, Fe, I,K, Se, Sr, Th and Zn were determined in total diet samples and also in individualfood materials which constitute the typical Indian diet. Instrumental neutronactivation analysis (INAA) and radiochemical neutron activation analysis (RNAA)were employed for the analysis. Whereas the elements Fe, Co, Cr, Se and Znare important from the view point of their role in nutrition, the elementsCs, K, Sr and Th are of importance in radiation protection, and Ca and I havedual importance: both in nutrition as well as in radiation protection. Basedon the analysis of twenty total diet samples, prepared as per the data onthe dietary intake pattern of four provinces of India and the data on intakepattern of an average adult Indian, the geometric mean (GM) intake of variouselements was estimated to be 0.33 g (0.2–0.67) for Ca, 16.5 µg(8.3–31.1) for Co, 52.3 µg (35.1–131) for Cr, 4.7 µg(2.79–11.8) for Cs, 94.6 µg (60.6–201) for I, 1.90 g (1.25–3.54)for K, 1.13 mg (0.78–2.97) for Sr, 0.76 µg (0.45–1.66) forTh, 15.9 mg (10.2–34.3) for Fe, 56.3 µg (27.6–105.3) forSe and 8.6 mg (5.1–16.7) for Zn. Some of the important individual foodmaterials, such as cereals, pulses, milk, vegetables etc., were also analysedfor these elements to observe the contributions of the individual food materialsto their daily dietary intake. The results of the analysis showed that inthe case of Cs, K, Sr, Th, Fe, Zn and Co, almost 50% of the daily dietaryintake of the above stated elements is contributed by cereals and pulses.In the case of Ca however, significant amount is contributed by milk and incase of I, iodised salt could make significant contribution. The data collectedso far, for Se and Cr, was not sufficient to draw any definite conclusion.     

Study of the Nutritional Status of Maternal Breast Milk in Preterm Infants in Nigeria

Instrumental neutron activation analysis (INAA) and proton induced X-ray emission (PIXE) analysis were used to determine the concentration of 13 elements in the breast milk collected within the first week of lactation and after morning feed from 16 pre-term mothers and 20 term mothers. The results of the study show that pre-term milk has a significantly higher concentration of Cl, Cu, Fe, K, Mg, Mn, Na and Zn while term mothers have a significantly higher concentration of P and Br. No significant differences were, however, found in the mean concentration of Al, Ca, I and Rb. Furthermore, the mean concentration for most of the elements found in the breast milk fall within the range of the concentrations obtained for the commercial infant milk formulae.     

Column Solid-Phase Extraction with 2-Acetylmercaptophenyldiazoaminoazobenzene (AMPDAA) Impregnated Amberlite XAD-4 and Determination of Trace Heavy Metals in Natural Waters by Flame Atomic Absorption Spectrometry

A column solid-phase extraction (SPE) preconcentration method was developed for the determination of Cd, Co, Cu, Ni and Zn ions in natural water samples by flame atomic absorption spectrometry. The procedure is based on the retention of analytes in the form of 2-acetylmercaptophenyldiazoaminoazobenzene (AMPDAA) complexes on a short column of AMPDAA-XAD-4 resin from buffered sample solution and subsequent elution with hydrochloric acid plus sodium chloride. Important SPE parameters were optimized using model solutions. The loading half-time, t_1/2, for Cd, Co, Cu and Zn was found to be less than 5min, and for Ni the value was 12min. The detection limit for Cd, Co, Cu, Ni and Zn was 0.028, 0.064, 0.042, 0.023 and 0.16µgL^–1, respectively, and the quantification limit was 0.043, 0.11, 0.099, 0.044 and 0.29µgL^–1, respectively. The AMPDAA-XAD-4 resin has good selectivity for Cd, Co, Cu, Ni and Zn over several electrolytes, especially over earth alkaline metals with tolerance limits of 0.05molL^–1. The method was validated by analysing a standard reference material (GBW 08301), and it was found that the results agree with those quoted by the manufactures. The developed method was applied to the determination of trace metal ions in tap water and river water samples with satisfactory results.     

Determination of Essential and Toxic Elements in Vegetables from South Korea

This study reports the determination of trace essential (Co, Cr, Cu, Se, and Zn) and toxic (Al, As, Cd, Hg, and Pb) elements in greenhouse tomatoes, peppers, and cucumbers from supermarkets of Seoul, Busan, Gangneung, Daegu, Daejeon, and Gwangju, South Korea using inductively coupled plasma mass spectrometry, inductively coupled plasma optical emission spectroscopy, and direct mercury analysis. The methods were validated by linearity, limits of detection and quantification, precision, accuracy, and recovery measurements that provided satisfactory results in all cases. Among the essential trace elements, Zn was found to have the highest concentrations (0.84–2.5?mg/kg) followed by Cu (0.21–0.62?mg/kg) and Cr (0.01–0.06?mg/kg). The mean concentrations (mg/kg) of the toxic elements were in the order Al?>?Pb?>?As?>?Cd?>?Hg for tomatoes and cucumbers and Al?>?Pb?>?Cd?>?As?>?Hg for peppers; all were below the permissible limits set by World Health Organization for human consumption. The estimated dietary intake, target hazard quotients (THQs), and hazard indices of the samples were within safe levels. The combined THQ values for the toxic elements in the vegetables were from 0.002 to 0.012 with significant contribution from arsenic, aluminum, cadmium, and mercury. The results of this study show that trace and toxic elements in the analyzed vegetables do not impose any serious health harmful effects for the population upon consumption.     

Evaluation of portable XRF instrumentation for assessing potential environmental exposure to toxic elements

Portable instruments based on X-Ray Fluorescence Spectrometry (XRF) have the potential to assist in field-based studies, provided that the data produced are reliable. In this study, we evaluate the performance of two different types of XRF instrument (XOS prototype and Thermo Niton XL3t). These two XRF analysers were evaluated in a laboratory setting, and data were reported for 17 elements (As, Ba, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, Sn, Sr, Ti, V, and Zn). Samples analysed (n = 38) included ethnic herbal medicine products (HMPs), ethnic spices (ES), and cosmetic products (CPs). Comparison analyses were carried out using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). In general, results reported for Cd, Cu, and Pb by the XOS prototype analyser, using the non-metal mode, were negatively biased (5–95%) as compared to ICP-OES. In contrast, results reported for Pb, As, Cd, Cu and Zn by the Niton, using the soil mode, were positively biased, in some instances (Cd) by up to four orders of magnitude. While the sensitivity of both instruments was insufficient for reliably ‘quantifying’ toxic elements below 15 mg/kg, XRF was still capable of positively ‘detecting’ many elements at the low single-digit mg/kg levels. For semi-quantification estimates of contaminants at higher levels, and with limited sample preparation, both XRF instruments were deemed fit for the purpose. This study demonstrates that modern XRF instrumentation is valuable for characterising the elemental content of food, cosmetic, and medicinal products. The technology is particularly useful for rapidly screening large numbers of products (100’s per day) in the field, and quickly identifying those that may contain potentially hazardous levels of toxic elements. Toxic elements can be confirmed by examining the raw spectrum, and the limitations of factory-based calibration are generally manageable for field-based studies.     

Homo and heteronuclear complexes of dioxime ligands

The mononuclear fragments [Cu(HDopn)(OH)2]+ and [Cu(HPopn)(OH)2]+, [H2Dopn=3,3-(trimethylene- dinitrilo)-dibutan-2–one dioximate and H2Popn, = 3, 3-(phenylenedinitrilo)-dibutan-2–one dioximate] were used to prepare four binuclear complexes [(OH2)Cu (Dopn)Cu(ditn)]2+, [(OH2)Cu(Dopn)Ni(ditn)(H2O)]2+ (ditn=diethylenetriamine) and [(OH2)Cu(Popn)Cu(L) (H2O)]2+ (L=2,2-bipyridine or 1,10–phenanthroline). Two trinuclear complexes, [{Cu(Popn)(OH2)}2M (H2O)n]2+ (when M=CuII, n=1; M=ZnII, n= 2), have been synthesised and characterised by elemental analyses, f.a.b. mass, i.r., electronic, e.s.r. spectroscopy and variable temperature (5–300K) magnetic susceptibility measurements. A strong antiferromagnetic interaction (J=–545cm–1 to –700cm–1) has been found for the binuclear copper(II) complexes. The X-band e.s.r. spectra of these complexes at 300K and for trinuclear complexes at 120K indicate square-pyramidal geometry for the copper centres with a (dx2–y2)1 ground state. The binuclear complex of copper(II)–nickel(II) centres with antiferromagnetic interaction (J=–107 cm–1) is described, and moderately strong zero-field splitting within the quartet state leads to Kramers doublet, as indicated by X-band e.s.r. spectra of this complex. The trinuclear copper(II) complex with an antiferromagnetic interaction (J= –350cm–1) is also described. The heterometallic trinuclear copper(II)–zinc(II)–copper(II) system shows a very weak interaction (J–1cm–1).     

Preconcentration and XRF-determination of heavy metals in hair from Sudanese populations

Energy-dispersive X-ray fluorescence analysis was applied for the analysis of hair. The hair samples were digested in a mixture of nitric and perchloric acid and the heavy metals were precipitated with ammonium pyrrolidine dithiocarbamate. The accuracy, precision and recovery of the method for the elements Fe, Ni, Cu, Zn and Pb were evaluated through the analysis of a standard hair sample. The procedure was applied to the analysis of hair from an occupationally exposed group of Sudanese workers and a control group. The hair of the exposed group showed a range of 80–550 ppm Fe, 6–12 ppm Cu, 57–190 ppm Zn and 70–3700 ppm Pb, while that of the control group had a range of 60–310 ppm Fe, 7–22 ppm Cu, 89–170 ppm Zn and 3–17 ppm Pb.     

A Test Method for Determining Total Metals with an Indicator Paper and Its Performance Characteristics

A test procedure is proposed for determining total metals (Cd, Co, Cu, Fe, Hg, Ni, and Zn) using irregular 1-(2-carboxyphenyl)-5-(4-methyl-6-methoxypyrimidine-2-yl)formazan-6-cellulose as an indicator paper. Regions of unreliable color reactions were determined for each of the metals and total metals present in equal concentrations. Statistical processing showed that the Weibull distribution function best describes the experimental results in the unreliable reaction regions. Unreliable reaction was observed in the range (3.6–4.4) × 10^–3 mg/L for the test procedure with preconcentration and in the range 1.7–3.4 mg/L for the procedure without preconcentration; the detection limits are 4.4 × 10^–3 and 3.4 mg/L, respectively. A synergetic effect of the component mixture was observed in determining total metals. The visual, reflectometric, and atomic absorption determination of total Co, Cu, Fe, Ni, and Zn in natural and tap water was studied; it was shown that the results of test determination agree well with the data of other methods.     

Validation of the Tessier scheme for speciation of metals in soil using the Bland and Altman test

The Tessier extraction method was used for speciation of Cu, Pb, Zn, As, Fe and Mn in a large concentration range in contaminated soil with various mineralogical compositions. The results were compared by X-ray fluorescence spectrometry (XRF) as a reference method using the Bland and Altman test. A sum of five fractions (exchangeable, bound to carbonates, Fe-Mn oxides, organic matter and residual forms) was compared with the total content determined on solid matrix by the reference method. A good agreement between the methods in the whole concentration range was found for Cu, Zn, As, and Fe. For Mn and Pb, XRF was found suitable to verify the sequential extraction only for concentrations above 250 mg kg⁻¹. This was a consequence of a poorer reproducibility of Pb extraction using the Tessier scheme due to a great difference in the mineralogical composition and the diversity of the Pb species identified in soil. The poorer result of Mn was attributed to the spectral interference of Fe in XRF. Presented at the 34th International Conference of the Slovak Society of Chemical Engineering, Tatranské Matliare, 21–25 May 2007.     

Determination of Selenium(IV) by Stripping Voltammetry at a Mercury-Film Electrode

A procedure was proposed for the determination of selenium(IV) by stripping voltammetry on a mercury-film electrode at an electrolysis potential of +0.4 V versus the saturated silver–silver chloride reference electrode in a 1 M H₂SO₄ solution. The current of the cathodic peak is a linear function of the selenium(IV) concentration in the range from 5 × 10^–3 to 3 × 10^–1 mg/L (6.3 × 10^–8 to 3.8 × 10^–6 M) at a time of electrolysis of 30 s (t _el). The detection limit for selenium is 1 × 10^–4 mg/L (1.3 × 10^–9 M) at t _el = 300 s. It was shown that selenium(IV) can be determined in the presence of 10 mg/L Zn(II), 1 mg/L Cd(II), 0.5 mg/L Pb(II), and 0.2 mg/L Cu(II). A procedure for the determination of selenium in natural, mineral, and potable water was proposed.     

Lead determinations in human bone by particle induced X-ray emission (PIXE) and graphite furnace atomic absorption spectrometry (GFAAS)

Chronic lead (Pb) intoxication has been linked to Alzheimer's disease (AD). Lead, like many heavy elements, tends to accumulate in bone. PIXE is a powerful analytical tool which permits the determination of Pb at the g/g level without requiring sample digestion. GFAAS is one of the most sensitive methods for the determination of Pb and is capable of determining ng/g levels in solution. For bone analyses by GFAAS, sample dissolution and a matrix modifier are required. Rib bone samples were analyzed for Pb by PIXE and GFAAS. IAEA Animal Bone (H-5) was used as a secondary standard for Pb with both methods to ensure accuracy. The range of Pb concentrations in human rib bone was 1.4–11.5 g/g for the trabecular surface by PIXE, 1.3–45 g/g for the cortical surface by PIXE, and 1.54–11.75 g/g for whole bone by GFAAS. No significant difference (p>0.05) was found for AD versus control for either surface or for whole bone.