Graphite Furnace Atomic Research Articles

Analyzing American Brand and Chinese Counterfeit Eyeshadows for Heavy Metals

Counterfeit cosmetics are a large problem in the world today because they are cheap and easy to purchase. However, many are unaware of the counterfeit cosmetics’ ingredients as they are not mandated to comply with the American Food and Drug administration requirements. Counterfeit cosmetics may have ill-effects on a person’s body that are irreversible. This study aimed to compare three brands of American eyeshadows with their Chinese counterfeits and determine their lead, iron, copper, and arsenic concentrations. In total, there were three samples tested from each brand, making an overall total of eighteen samples. The samples were acid digested and analyzed through an Atomic Absorption Spectrometer (AAS) and Graphite Furnace Atomizer (GFA). Preliminary results showed varying amounts of iron, copper, lead, and arsenic found in some of the samples from both the American brands and their Chinese counterparts. These heavy metals can be absorbed through the skin causing effects such as nausea, anemia, nerve damage and other life-threatening events. Consumers should be more aware of these counterfeit products and the heavy metal presence that may be accidentally or intentially added in these products and what they can do to a person’s body.

Determination of lithium in dried blood spots and dried plasma spots by graphite furnace atomic absorption spectrometry: Method development, validation and clinical application

Therapeutic drug monitoring (TDM) has become a standard of care for the mood stabilizer lithium (Li+). Dried Blood Spots (DBS) and Dried Plasma Spots (DPS) are promising alternative sampling strategies for TDM, which allows simple and cost-effective logistics in many settings, particularly in Developing Countries. DBS and DPS are of particular interest to Li + TDM for allowing the estimation of Li + erythrocyte levels. Thus, the aim of this study was to develop and validate an assay for the determination of Li+ in DBS and DPS by Graphite Furnace Atomic Absorption Spectrometry (GFAAS), and to evaluate its application in a clinical setting. Li+ was extracted from one 8 mm DBS disc punch with nitric acid 4.5% and from one 6 mm DPS disc punch with diluent solution (HNO3 1% + Triton 0.1%) and injected into GFAAS. The method was applied to Li + TDM in 43 patients with mood disorder. The assays were linear from 0.10 to 3.0 mEq L−1 (r > 0.99), precise, with CV 3.6–7.2% for DBS and 4.6–9.3% for DPS samples, and accurate, with accuracy values of 97–109% and 98–106% for DBS and DPS samples, respectively. Li+ was stable in dried samples during twenty days at up to 42 °C. The DBS assay accuracy and recovery were not influenced by blood hematocrit. The patients presented Li + serum concentrations of 0.18–1.1 mEq L−1 and 0.17 to 0.92 mEq L−1 in DBS and 0.15 to 0.99 mEq L−1 in DPS samples. DPS had comparable Li + concentrations to the ones found in fresh serum samples. With DBS samples it was possible to estimate the Li + erythrocyte to plasma concentration ratio (LiR). The findings of this study support the clinical application of DBS and DPS samples for the TDM of Li+.

Preparation of an L-Cysteine Functionalized Magnetic Nanosorbent for the Sensitive Quantification of Heavy Metal Ions in Food by Graphite Furnace Atomic Absorption Spectrometry

A typical l-cysteine functionalized magnetic mesoporous nanosorbent (Cys–Si–MNPs) was successfully synthesized and characterized by transmission electron microscopy, the nitrogen adsorption–desorption isotherm and X-ray photoelectron spectroscopy. The results showed that Fe3O4 magnetic core was shelled by mesoporous silica, and the capacity of thiol group with strong affinity to various heavy metal ions was as high as 238 mg g−1. Using the obtained l-cysteine functionalized magnetic nanoparticles as the adsorbent, a graphite furnace atomic absorption spectrometry (GFAAS) method was developed for the determination of Pb2+, Cd2+, Cu2+, Cr3+, and V5+ in food. The experimental parameters affecting the separation performance including the pH of the sample solution, adsorbent mass, contact time, and co-existing ions were investigated systematically. Using the optimized conditions, the detection limits were as low as from 0.006 to 0.36 μg L−1. The precision of the method was evaluated by the relative standard deviation (n = 11) at limit of quantification (LOQ) of each target ion and was less than 6.0%. The proposed method was further successfully applied for the determination of the target ions in certified reference materials including GBW10043 rice, GBW 10023 laver, and GBW 10050 shrimp. The obtained recoveries were in the range from 89% to 102% with relative standard deviations (n = 3) lower than 8%.

Extraction of Cu, Fe, Mn, and Ni from Margarine Samples Using Extraction Induced by Emulsion Breaking Procedure Prior to Graphite Furnace Atomic Absorption Spectrometry and Comparison of Results to Provisional Tolerable Daily Intake Values.

The emulsion induced by emulsion breaking (EIEB) procedure was previously reported for the extraction of copper, iron, manganese, and nickel from liquid oil samples such as vegetable oil. To optimize the EIEB procedure for determination of copper, iron, manganese, and nickel in solid oil (margarine) samples by Graphite Furnace Atomic Absorption Spectrometry (GFAAS). The extraction procedure uses a surfactant in nitric acid to form an emulsion followed by heating to break the emulsion. Optimization included variation of the test portion size, the type and concentration of the surfactant, the concentration of nitric acid in the aqueous solution, the emulsion agitation time, heating temperature, and the time required to break the emulsion. Mean element concentrations of 11 margarine samples were in the following ranges: Cu 0.031-0.131 µg/g, Fe 5.7-24.9 µg/g, Mn 0.542-1.11 µg/g, and Ni 0.108-0.134 µg/g. Under the optimized extraction conditions, the detection limits (µg/kg) were 4.8, 13, 1.5, and 23 for Cu, Fe, Mn, and Ni, respectively. The accuracy of the extraction procedure was determined by comparison to commonly used microwave digestion procedure. The EIEB results were not statistically different from the microwave digestion results when analyzed by GFAAS as determined by the statistical tests. The EIEB procedure was shown to be equivalent to the commonly used microwave digestion procedure for extraction of analytes from margarine samples. The optimized EIEB extraction procedure is simple, rapid, low cost, and environmentally friendly. It has improved detection limits and allows calibration with aqueous standards.

Semi-continuous Monitoring of Cr(VI) and Cr(III) during a Soil Extraction Process by Means of an Ion Transfer Device and Graphite Furnace Atomic Absorption Spectroscopy.

Electrodialytic separation of Cr(VI) and Cr(III) followed by graphite furnace atomic absorption spectrometry for monitoring of soil extraction was studied. The sensitivity was improved by in-line purification of the solutions and bi-polar pulse cleaning. The detection limit for both Cr(VI) and Cr(III) was 0.01 μg L-1. The system was successfully used to monitor the concentration change during soil extraction with dual solution line filtration. The results demonstrate the difference in concentration changes with the different sources of Cr(VI).

URINARY LEAD CONCENTRATION IN CHRONIC KIDNEY DISEASE PATIENTS AT NEPHROLOGY CLINIC IN SABAH

Presently, scientific knowledge on the association between urinary lead concentration and renal profile is limited, especially on the characteristic of urinary lead that could aggravate existing kidney disease. This study aims to determine the concentration of urinary lead with serum creatinine and blood urea nitrogen in chronic kidney disease patients and to identify the influences of confounding factors and the blood pressure on the chronic kidney disease patients. Graphite Furnace Atomic Absorption Spectrometer was used to determine the urinary lead concentration. The differences and correlation of urinary lead with serum creatinine, blood urea nitrogen and diastolic blood pressure between the chronic kidney disease patients and control groups were assessed using Mann Whitney U and Spearman correlation tests. Our findings indicated a significantly higher urinary lead concentration in the chronic kidney disease group compared to the control group (p-=0.002). Nevertheless, there is a weak relationship between urinary lead with serum creatinine, blood urea nitrogen and diastolic blood pressure in the chronic kidney disease group (r values: -0.123, 0.101, and 0.127). In addition, sociodemographic factors did not influence the concentration of urinary lead (p>0.05). The urinary lead concentration in the chronic kidney disease group is not substantial, thus the evidence of urinary lead accumulation in chronic kidney disease group who have yet to start renal replacement therapy is inconclusive.

Assessment of exposure to nickel intake with selected cereal grains and cereal-based products.

Cereal grains and their products are among the basic components of the diet all over the world. Their consumption varies depending on the dietary habits in each country. Apart from ingredients valuable from a health point of view, these products can also be a source of contaminants. The European Food Safety Authority (EFSA) included these foodstuffs in the group of main contributors to the dietary exposure to nickel by different groups of the population. The aim of the studies was to determine the nickel content in cereal grains and selected cereal products commercially available in Poland and to assess the exposure of consumers to nickel intake with these foodstuffs. A total of 56 samples of cereal grain and cereal products from trade were tested. Nickel content was determined after microwave mineralization of the samples by atomic absorption spectrometry with a graphite furnace atomization (GFAAS). The estimated exposure for the different groups of the population was assessed and compared with the Tolerable Daily Intake (TDI) value established by the European Food Safety Authority based on an updated risk assessment at 13 μg/kg body weight (b.w.) per day. The mean (MB) and 95th percentile (MB) nickel content in investigated samples of cereal grains and their products were 0.66 mg/kg and 1.93 mg/kg. The mean content of Ni in the analyzed samples of grains was 1.16 mg/kg. Obtained results in this group of products ranged from 0.10 mg/kg for rye to 4.80 mg/kg for millet. In the group of grain products, the mean (MB) concentration of nickel was 0.61 mg/kg (95th percentile (MB) 1.84 mg/kg). The highest nickel level was determined in the samples of bran, groats, and flakes compared to other grain-based products. The highest content of Ni in the group of cereal products was found in the samples of roasted buckwheat 1.81 mg/kg and oat flakes 2.53 mg/kg. Significantly lower nickel content was observed in barley groats as well as for pasta and flour. The estimated average exposure of adults and children to nickel intake with grains and grain-based products ranged from 1.1% to 13.4% of TDI and it does not pose a health risk for consumers. Based on the obtained results, it was found that the nickel content in the tested samples of cereals and their products does not pose a health risk, even though the contamination of individual samples was significant.

Evaluation of two sample preparation methods for the determination of cadmium, nickel and lead in natural foods by Graphite Furnace Atomic Absorption Spectrophotometry

Environmental pollution allows heavy metals to interact with ecosystems, bioaccumulating and passing through the food chain. Animals and human scan consume contaminated species and reach toxic and harmful concentrations in their organisms. While there are international regulatory frameworks for heavy metal contents, these are not always known or suitable for local conditions. This situation calls for the development of locally-applicable analytical methods for the determination of heavy metal concentrations in common vegetal and animal food products. Two established methods (AOAC999.11, based on sample drying and calcination, and IPNAC-06-00, based on microwave-assisted acid digestion) were comparatively tested at the CESAQ-PUCE laboratory in Quito, Ecuador, to determine their suitability. Sample matrices used were non industrial, non-organic tomato, lettuce, and beef commonly found in local markets. Heavy metals tested were cadmium, nickel, and lead. Test guidelines and comparative parameters were based on AOAC(2002) and included quantification limits, repeatability variation coefficients, intermediate precision percentages, accuracy and calculated expanded uncertainties. Unlike method AOAC999.11, method IPNAC 06-00 performance for all parameters was with in the range of recommended expected values as per AOAC, and was therefore deemed more suitable to be applied under the local CESAQ-PUCE laboratory conditions. The validation of method IPNAC-06-00 demonstrated its local applicability. In addition, IPNAC 06-00 can beused by similar laboratories to assess contaminants concentrations and improve the base line information concerning human exposure to toxic metals.

Simultaneous Determination of Chromium and Iron in Powdered Milk Using High-Resolution Continuum Source Graphite Furnace Atomic Absorption Spectrometry

This work proposes the simultaneous determination of chromium and iron in powdered milk samples using high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GF AAS) and sample digestion in microwave oven using nitric acid and hydrogen peroxide. The method was established using the primary line (357.869 nm) for chromium and the adjacent secondary line (358.120 nm) for iron while employing aluminum as the chemical modifier. The absorbance signals were measured by peak area using three pixels for both elements. Chromium and iron can be determined in powdered milk samples by the external calibration technique with limits of quantification of 28 ng g−1 for chromium and 19 μg g−1 for iron. The precision was evaluated by using a milk sample with chromium and iron concentrations of 0.76 μg g−1 and 151.3 μg g−1, respectively. The results expressed as relative standard deviation (n = 10) were 2.6% for iron and 3.9% for chromium. The method accuracy was confirmed by the analysis of a milk sample by a comparison of results obtained by the proposed method and those found by employing inductively coupled plasma mass spectrometry (ICP-MS). Five samples were analyzed, and the analyte concentrations found varied from 408 to 805 ng g−1 for chromium. Among the five samples, three had an iron concentration lower than 19 μg g−1 and in the other two samples, the iron concentrations varied from 151 to 199 μg g−1.

Oxide formation as probe to investigate the competition between water and alcohol molecules for OH species adsorbed on platinum

The creation of defects on the surface of Pt(111) and Pt(100) and the dissolution of Pt were used as probes to investigate the oxidation of the surface in the absence and in the presence of methanol, ethanol, glycerol and ethylene glycol. Electrochemical and Graphite Furnace Atomic Absorption Spectrometry showed that in the presence of ethanol, glycerol and ethylene glycol, in the same potential window, the formation of defects is decreased in comparison to the oxidation of platinum in the absence of these alcohols. Since both the oxidation of the alcohols and the oxidation of the surface depend on PtOH formation, the competition for this species can displace the potential at which the oxidation of the surface oxidation to PtO is favored in the presence of ethanol, glycerol and ethylene glycol. On the other hand, the presence of methanol does not influence the oxidation and subsequent disordering of the surface, possibly because this reaction takes place in parallel with platinum oxidation to PtO.

Determination of heavy metals (lead, cadmium, arsenic, and mercury) in authorized and unauthorized cosmetics

Aim: The present study evaluates lead, cadmium, arsenic, and mercury contamination in lipsticks, mascara, eye shadow, and eyebrow pencils, and compares the amounts of these toxic elements in both legal and contraband products.Background: The presence of heavy metals in cosmetics is of major concern, and requires constant monitoring to ensure the safety of consumers. Cosmetics contaminated with heavy metals can lead them to accumulate in the skin, while the further migration of these toxic elements to blood vessels can cause subsequent difficulties.Material and methods: The graphite Furnace Atomic Absorption Spectrometry (GFAAS) and Direct Mercury Analyzer (DMA) techniques were used.Results: The data indicate that the lead content in the products did not exceed the acceptable limit of the Federal Office of Consumer Protection and Food Safety of Germany (BVL), and that the cadmium values in all products were significantly lower than the limit set by the BVL. The arsenic contents of lipsticks, eye shadows, and eyebrow pencils was significantly higher than the BVL standard, while the mercury content was far below the BVL standards, so there seems to be no concern associated with this toxic element. Legal cosmetics showed better results, except for mascara, which had higher amounts of arsenic than contraband. The higher contents of arsenic in contraband eye shadows and eyebrow pencils is an issue that should be taken into considerations by the relevant authorities.Conclusion: The authors suggest further analysis of the toxic elements in cosmetics and better monitoring of both imported and contraband cosmetics. Moreover, consumers’ knowledge of the potential risks of the frequent application of cosmetic products should be improved.

Assessment of Pollution Status of Soils and Vegetables Irrigated by Awash River and its Selected Tributaries

This assessment was done to determine the concentrations of Cadmium (Cd), Chromium (Cr), Copper (Cu), Lead (Pb) and Manganese (Mn) in soil and vegetable (Spinach) samples collected in some farmlands irrigated with Awash River. Graphite Furnace Atomic Absorption Spectrometer was used for analyzing heavy metal concentrations. The test results showed that in the soil samples, from five heavy (Cd, Cr, Cu, Mn, and Pb) metals Cr and Mn were detected in all the soil samples collected from farmlands in the Lower, Middle, and Upper Awash River Basin.

Effective and High-Throughput Analytical Methodology for the Determination of Lead and Cadmium in Water Samples by Disposable Pipette Extraction Coupled with High-Resolution Continuum Source Graphite Furnace Atomic Absorption Spectrometry (HR-CS GF AAS)

A new procedure for the preconcentration of trace amounts of free Pb and Cd by disposable pipette extraction (DPX) is proposed herein. Recycled cork is used as a biosorbent and the procedure is completely free of organic solvents. The cork was reduced to a powder and characterized by scanning electron microscopy. Several parameters that influence the preconcentration of Pb and Cd with DPX-cork, such as the sample pH, number of extraction cycles, biosorbent mass, and percentage of acid in the desorption step, were studied. The tolerance of DPX-cork with respect to 10 potential interfering ions was also evaluated. Coupled with the high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GF AAS) technique, the sample preparation method allowed the analytical limits required for quality control (according to the permitted limits established by legislation) to be obtained. The limits of detection for the extraction of a 3.5-mL water sample were 200 ng L−1 for Pb and 100 ng L−1 for Cd. The relative standard deviations were around 7.5% for Pb and 8.0% for Cd. The optimized method was successfully applied to the determination of Cd and Pb in two certified reference materials (water and wastewater) and five water samples (collected from a mangrove, a creek, and the sea).

Aluminium release by coated and uncoated fluid-warming devices.

The use of fluid-warming systems is recommended for infusion rates >500ml.h-1 to avoid peri-operative hypothermia. Some fluid-warming devices use disposable aluminium-heated plates for heat transfer, but there is no protective coating to separate the fluid from the heated aluminium surface. It is unknown if this could promote release of aluminium into infusion fluids. We investigated a coated (Fluido compact) and an uncoated (enFlow) fluid-warming device using normal saline or balanced electrolyte solution as infusion fluids, pumped through the heated disposables at flow rates of 2, 4 and 8ml.min-1 for 60min each. Aluminium concentrations in the fluid samples were analysed using graphite furnace atomic absorption spectrometry. With saline the coated and uncoated devices yielded aluminium concentrations below the level of quantification (<128μg.l-1 ). Similarly, balanced electrolyte solution in the coated device yielded aluminium concentrations <128μg.l-1 . However, balanced electrolyte solution in the uncoated device yielded aluminium concentrations of up to 6794 (3465-8002 [1868-7421]) μg.l-1 . Repeating this last study at a flow rate of 2ml.min-1 resulted in quite high aluminium concentrations when the uncoated device was not heated (~1000μg.l-1 ) and higher concentrations after the device was heated. We conclude that using uncoated aluminium plates in fluid-warming systems can lead to a risk of administering potentially harmful concentrations of aluminium when balanced crystalloid solutions are used. The mechanism is unclear, but heat is in part involved. Coating for aluminium within medical devices in direct contact with infusion fluids should be recommended.

Simultaneous multi-element determination in electrothermal atomic-absorption spectrometry with electrothermal atomization

A discussion of the prospects for creating a multi-element atomic absorption (AA) spectrometer leads to the conclusion regarding the expediency of using spectral devices of relatively low resolution. Previous studies showed that the spectrometer with instrumental bandwidth 0.12 nm equipped with a CCD detector could provide the absorption measurements within a wavelength range of 200 – 400 nm using low-noise radiation sources, e.g., deuterium or low current xenon lamps. The rate of data acquisition was sufficient for vapour spectra monitoring during the pulse atomisation in graphite furnace atomizer. The loss in sensitivity due to low resolution is compensated by the possibility of direct determination of several elements in a single liquid or powder sample. Feasibility of multi-element simultaneous AA spectrometry depends on the efficiency of atomization technique and technology of data processing. The concurrent problems are discussed by the example of new calculation algorithm and its application to the analysis of multi-element nitrate and halogen containing reference materials. It is shown that linearization of the calibration curves for about 10 – 15 elements, which are not subject to chemical impacts, can be carried out automatically in a concentration range up to 4 – 5 orders of magnitude with 5 – 10 % deviation from the linearity at the ends of the interval. For the elements forming stable molecular compounds further improvement of the atomization technique is required.

Exposure assessment of the population in Poland to the toxic effects of nickel from vegetable and their products

According to the European Food Safety Authority (EFSA), vegetable and vegetable products can significantly contribute to dietary nickel intake. Consumption of vegetable across European Union can vary significantly and depends on consumption habits in individual Member States. Toxicity of Ni is dependent on the chemical form, the route of exposure and solubility of nickel compounds. Determination of nickel content in commercially available vegetables and vegetable products and assessment of consumer exposure to Ni intake with these groups of foodstuffs. 66 samples of vegetables and their products were analysed for nickel content. Nickel was determined after microwave mineralization of samples by atomic absorption spectrometry with a graphite furnace atomization (GFAAS). Nitric acid and perhydrol were used for the mineralization of the samples. The estimated exposure for adults and children was compared with the tolerable daily intake (TDI -Tolerable Daily Intake) set by the European Food Safety Authority at 2.8 μg /kg body weight (b.w.) per day. Mean (MB-middle bound) Ni content from all investigated vegetable samples was 0.09 mg/kg (95th percentile MB 0.23 mg/kg). In vegetable products, mean Ni concentration was 0.191 mg/kg (95th percentile: 0.67 mg/kg). The highest nickel level was determined in the sample of roman lettuce (0.32 mg/kg), whereas lowest contamination was observed in the sample of onion (0.04 mg/kg). Contamination of investigated fruiting and leaf vegetable with nickel was slightly higher than root and bulb vegetables. The estimated average adults exposure to nickel from vegetable taking into account maximum absorption was 4.8% of TDI and 16.8% of TDI and does not pose a health risk. Exposure to nickel from vegetable products was 1.9% and 6.8% TDI, respectively. Obtained results demonstrate that dietary nickel intake from vegetables and their products do not constitute a significant health threat to consumers in Poland.

Comparative Quantification Study of Arsenic in the Groundwater and Biological Samples of Simri Village of Buxar District, Bihar, India.

Background:In the entire world, about 200 million populations are exposed to arsenic poisoning in groundwater. In Bihar, India about 50 million people are drinking arsenic contaminated water. This has caused various health related problems in the population like skin diseases, anemia, bronchitis, gastrointestinal problems, hormonal imbalance and cancer.Materials and Methods:In the present study, a total of 323 water samples were analyzed for the arsenic levels from the entire Simri village of Buxar district of Bihar and a total of 170 blood samples from the same household's subjects were collected for blood arsenic estimation through Graphite Furnace Atomic Absorption Spectrophotometer (Pinnacle 900T, Perkin Elmer, Singapore). Apart from this the correlation coefficient study between blood arsenic levels, age of the subjects, groundwater arsenic levels and depth of the handpumps were carried out.Statistical Analysis:Data were analyzed with statistical software (GraphPad Prism 5) and while scattered graphs were plotted through statistical software SPSS- 16.0.Results and Conclusion:The maximum arsenic concentration in the groundwater sample found during the study was 1929μg/L and in blood sample was 664.7μg/L. The study denotes high arsenic concentration in the drinking water of the village Simri with the highest concentration ever reported in this part of India. Furthermore, the blood samples have also been observed with high arsenic concentration in the village population which is also the highest reporting ever done in this area. The ill health of the village population also correlates our study.

Accumulation processes of trace metals into Arctic sea ice: distribution of Fe, Mn and Cd associated with ice structure

Biogeochemical cycling of trace metals in sea ice is important to the productivity of the Arctic Ocean. Unfortunately, the processes by which trace metals accumulate into sea ice are poorly understood. To gain a clearer understanding of the mechanisms behind trace metal accumulation, dissolved (D, <0.2 μm), and labile particulate (LP = Total Dissolvable – Dissolved) iron (Fe), manganese (Mn), and cadmium (Cd) concentrations were compared to the structure observed in sea ice. Samples were pre-concentrated via solid-phase extraction on NOBIAS Chelate PA-1 resin and analyzed on a Graphite Furnace Atomic Absorption Spectrometer. Using photographic analysis for the percentage of pore microstructure and δ18O analysis, sea ice structure was determined to be snow ice, granular ice (frazil ice), mixed ice (granular and columnar ice) and columnar ice. Salinity and nutrients were low, indicating brine drainage and multi-year ice. High trace metal concentrations in snow ice indicated meteoric snow was a source of trace metals to sea ice. High concentrations of LPFe in granular ice indicated entrainment of suspended particulate trace metals by frazil ice during the formation of the granular ice structure. Whereas the high concentrations of DFe and DMn in granular ice may have been due to reduction from LPFe and LPMn after particle entrainment, indicating chemical transformation processes. Low dissolved and labile particulate trace metal concentrations in mixed and columnar ice indicated a release due to brine drainage. Our study clearly indicates that the differences observed in trace metals among sea ice structures, showed that sea ice formation, chemical reduction and brine release were the processes driving trace metal accumulation and release in the Arctic sea ice.

Graphite Furnace Atomic Absorption Spectrometric Evaluation of Iron Excretion in Mouse Urine Caused by Whole-Body Gamma Irradiation.

A procedure for the determination of iron in mice urine using graphite furnace atomic absorption spectrometry was developed. The mice urinary samples contain many organic compounds in the matrix, whose concentrations are approximately 20%, and the value is 30-fold higher compared to those found in human urine. Moreover, only 0.2mL or less of urine was obtained as a sample volume per urination event. It was difficult to decompose the organic materials in the samples by wet digestion using mineral acids and oxidising agents, because of the tiny volumes. In this experiment, raw urinary samples were placed directly into the graphite tube furnace for analysis. The organic contents were simply ashed during the preheating stages. To facilitate ashing in the furnace, air was invaded from the surroundings by interrupting the stream of argon gas. Atomic absorption was measured at 248.3270nm (wavelength for atomic absorption), with the background monitored at 247.0658nm (wavelength for background correction). The optimised instrument operating conditions precluded the use of chemical modification technique. The analytical procedures used are quite simple, i.e. an aliquot of raw urine sample was injected directly into the graphite tube furnace and was followed by a suitable heating programme with no chemical modifier. Therefore, this method is useful for scientists who are not familiar with delicate chemical experiments. The proposed analytical method was applied as a kind of biomarker by determining iron concentrations in urinary samples of mice, which were irradiated with 4Gy of gamma irradiation to their whole body. The time dependence of the iron concentration was determined, and the iron concentrations increased within 1day of irradiation exposure, then decreased to ordinal values after several days.

Determination of Cadmium Concentration in Milled and Brown Rice Grains Using Graphite Furnace Atomic Absorption Spectrometry.

Heavy metal pollution is a growing public health concern since it poses a food risk to public health via metal transfer. Cadmium is of particular concern because it is a potential carcinogen if exceed tolerable limits in the grain. Hence, it is important to monitor the cadmium content of rice before it reaches the market to ensure public healthy safety, especially in areas known to have high cadmium levels in soil. In this chapter, the method used to determine the concentration of cadmium in milled and brown rice grain samples is described. This method involves sample digestion with concentrated nitric acid and hydrogen peroxide and analysis of cadmium by Graphite Furnace Atomic Absorption Spectrometry (GF-AAS). Because cadmium concentrations are low in rice grains, quantification of cadmium content requires the use of a more sensitive instrument, such as GF-AAS.