Electrothermal Atomic Absorption Spectrophotometry Research Articles

Antibacterial Activity of Biodegradable Films Incorporated with Biologically-Synthesized Silver Nanoparticles and the Evaluation of Their Migration to Chicken Meat.

The food industry has been exploring the association of polymers with nanoparticles in packaging production, and active products are essential to increase the shelf life of food and avoid contamination. Our study developed starch-poly (adipate co-terephthalate butyl) films with silver nanoparticles produced with Fusarium oxysporum components (bio-AgNPs), intending to control foodborne pathogens. The bio-AgNPs showed activity against different Salmonella serotypes, including multidrug-resistant Salmonella Saint Paul and Salmonella Enteritidis, with minimum bactericidal concentrations ranging from 4.24 to 16.98 µg/mL. Biodegradable films with bio-AgNPs inhibited the growth of up to 106Salmonella isolates. Silver migration from the films to chicken was analyzed using electrothermal atomic absorption spectrophotometry, and the results showed migration values (12.94 mg/kg and 3.79 mg/kg) above the limits allowed by the European Food Safety Authority (EFSA) (0.05 mg/kg). Thus, it is necessary to improve the technique to avoid the migration of silver to chicken meat, since these concentrations can be harmful.

Post-mortem liver and bone marrow iron quantification in haemodialysis patients: A prospective cohort study.

SummaryBackgroundMagnetic resonance liver scans indicate that iron overload is common in haemodialysis (HD) patients. However, histological evidence is scarce.MethodsLiver biopsy and bone marrow aspirate were obtained in the first 24h post mortem from 21 adult HD patients. Biochemical liver iron content (LIC) was quantified by electrothermal atomization atomic absorption spectrophotometry. Tissue iron deposition was graded in the liver and bone marrow using Scheuer and Gale's criteria, respectively.FindingsMedian LIC was 42.5 (22.9-69.7) μmol/g and the majority (n=11; 57%) had mild to moderate liver iron overload (LIC >36 μmol/g). Scheuer grade was 2 (1-3) and 13 (62%) of liver biopsies had increased (> 1) iron deposition. In the bone marrow, median Gale's grade was 3 (3-4) and 9 (45%) patients had increased (>3) iron content.Contrary to old autopsy studies, done in the pre-erythropoiesis-stimulating agents (ESAs) era, both liver and bone marrow were iron replete and showed a positive correlation (r=0.71, p<0.001).Ferritin proved to have a good diagnostic accuracy for liver iron overload (0.87 95% CI 0.71-1.00) with an optimal cut-off value of 422 ng/ml. Haemoglobin was negatively associated with both LIC (r= -0.46, p=0.04) and iron content in the bone marrow (p=0.04). Patients with increased LIC had higher resistance to ESAs (p=0.02), yet no association with previous IV iron therapy.InterpretationIn the majority of HD patients there was iron accumulation in both the liver and bone marrow that associated with anaemia severity and resistance to ESAs, suggesting a blocking mechanism of iron's utilization.FundingNone.

Aluminum in Neurological and Neurodegenerative Disease.

With continuing cooperation from 18 domestic and international brain banks over the last 36years, we have analyzed the aluminum content of the temporal lobe neocortex of 511 high-quality human female brain samples from 16 diverse neurological and neurodegenerative disorders, including 2 groups of age-matched controls. Temporal lobes (Brodmann areas A20-A22) were selected for analysis because of their availability and their central role in massive information-processing operations including efferent-signal integration, cognition, and memory formation. We used the analytical technique of (i) Zeeman-type electrothermal atomic absorption spectrophotometry (ETAAS) combined with (ii) preliminary analysis from the advanced photon source (APS) hard X-ray beam (7 GeV) fluorescence raster-scanning (XRFR) spectroscopy device (undulator beam line 2-ID-E) at the Argonne National Laboratory, US Department of Energy, University of Chicago IL, USA. Neurological diseases examined were Alzheimer's disease (AD; N = 186), ataxia Friedreich's type (AFT; N = 6), amyotrophic lateral sclerosis (ALS; N = 16), autism spectrum disorder (ASD; N = 26), dialysis dementia syndrome (DDS; N = 27), Down's syndrome (DS; trisomy, 21; N = 24), Huntington's chorea (HC; N = 15), multiple infarct dementia (MID; N = 19), multiple sclerosis (MS; N = 23), Parkinson's disease (PD; N = 27), and prion disease (PrD; N = 11) that included bovine spongiform encephalopathy (BSE; "mad cow disease"), Creutzfeldt-Jakob disease (CJD) and Gerstmann-Straussler-Sheinker syndrome (GSS), progressive multifocal leukoencephalopathy (PML; N = 11), progressive supranuclear palsy (PSP; N = 24), schizophrenia (SCZ; N = 21), a young control group (YCG; N = 22; mean age, 10.2 ± 6.1year), and an aged control group (ACG; N = 53; mean age, 71.4 ± 9.3year). Using ETAAS, all measurements were performed in triplicate on each tissue sample. Among these 17 common neurological conditions, we found a statistically significant trend for aluminum to be increased only in AD, DS, and DDS compared to age- and gender-matched brains from the same anatomical region. This is the largest study of aluminum concentration in the brains of human neurological and neurodegenerative disease ever undertaken. The results continue to suggest that aluminum's association with AD, DDS, and DS brain tissues may contribute to the neuropathology of those neurological diseases but appear not to be a significant factor in other common disorders of the human brain and/or CNS.

Trace determination of Ag(I) after reduction to Ag nanoparticles and sol–gel entrapment by alginic acid hydrogel

The main goal of this work is development of an effective analytical method for trace determination of Ag(I). The novelty of the Ag(I) preconcentration–determination method is mainly referred to the material and the enrichment–detection process (alginic acid gel phase was employed in a pH-switched sol–gel entrapment/Ag fluorescence detection). Ag(I) was reduced to Ag nanoparticles (AgNPs) and then was enriched by the alginic acid hydrogel phase. Then, the formed gel phase (containing AgNPs) was dissolved in alkali solution prior to Ag detection. The enrichment method was highly compatible with spectrofluorimetry, electrothermal atomic absorption spectrometry (ETAAS) and spectrophotometry. Optimization of the reduction-enrichment procedure was performed employing spectrofluorimetry. The linear working range (LWR) and limit of detection (LOD) for Ag(I) determination were found as 0.1–25 and 0.017 µmol L− 1, respectively. The effects of various anions, cations and organic chemicals on Ag(I) determination were spectrofluorimetrically studied. The applied enrichment-ETAAS Ag(I) determination method showed the LWR and LOD as 0.2–6.9 and 0.05 nmol L− 1, respectively. Also, an enrichment factor equal to 30.3 was obtained for the preconcentration method. The method was successfully applied to determine Ag in different water samples, jewels, antimicrobial suspensions and waste X-ray films. X-ray diffraction, transmission electron microscopy, field emission-scanning electron microscopy and EDX-mapping were also employed to characterize the entrapped AgNPs in the alginic acid gel phase. The complimentary experiments showed the alginic acid gel was also applicable for quantitative recovery of silver from the waste radiographic films.

A new gold standard approach to characterize the transport of Si across cell membranes in animals.

Silicon (Si) is increasingly recognized as an essential trace element in animals, especially since the identification of mammalian Si transport systems and Si responsive genes not long ago. During many years, however, efforts to gain substantial insight into the biological role of this element in animals have achieved partial success due in part to the unavailability of validated protocols to study Si movement across biological membranes. To circumvent such limitations, we have developed a general transport assay in which cellular Si content was determined by automated electrothermal atomic absorption spectrophotometry. We have found this assay to provide great analytic sensitivity with Si detection thresholds of less than 1 µM, that is, below or very close to the concentration range of animal cells. We have also found this assay to provide valid and cost-effective determinations in Si transport studies while requiring workable quantities of samples. The protocol described here should thus become gold standard toward accelerated progress in the field of Si transport.

Aluminum in neurological disease - a 36 year multicenter study.

Aluminum is a ubiquitous neurotoxin highly enriched in our biosphere, and has been implicated in the etiology and pathology of multiple neurological diseases that involve inflammatory neural degeneration, behavioral impairment and cognitive decline. Over the last 36 years our group has analyzed the aluminum content of the temporal lobe neocortex of 511 high quality coded human brain samples from 18 diverse neurological and neurodegenerative disorders, including 2 groups of age-matched controls. Brodmann anatomical areas including the inferior, medial and superior temporal gyrus (A20-A22) were selected for analysis: (i) because of their essential functions in massive neural information processing operations including cognition and memory formation; and (ii) because subareas of these anatomical regions are unique to humans and are amongst the earliest areas affected by progressive neurodegenerative disorders such as Alzheimer’s disease (AD). Coded brain tissue samples were analyzed using the analytical technique of: (i) Zeeman-type electrothermal atomic absorption spectrophotometry (ETAAS) combined with (ii) an experimental multi-elemental analysis using the advanced photon source (APS) ultra-bright storage ring-generated hard X-ray beam (7 GeV) and fluorescence raster scanning (XRFR) spectroscopy device at the Argonne National Laboratory, US Department of Energy, University of Chicago IL, USA. These data represent the largest study of aluminum concentration in the brains of human neurological and neurodegenerative disease ever undertaken. Neurological diseases examined were AD (N=186), ataxia Friedreich’s type (AFT; N=6), amyotrophic lateral sclerosis (ALS; N=16), autism spectrum disorder (ASD; N=26), dialysis dementia syndrome (DDS; N=27), Down’s syndrome (DS; trisomy21; N=24), Huntington’s chorea (HC; N=15), multiple infarct dementia (MID; N=19), multiple sclerosis (MS; N=23), Parkinson’s disease (PD; N=27), prion disease (PrD; N=11) including bovine spongiform encephalopathy (BSE; ‘mad cow disease’), Creutzfeldt-Jakob disease (CJD) and Gerstmann-Straussler-Sheinker syndrome (GSS), progressive multifocal leukoencephalopathy (PML; N=11), progressive supranuclear palsy (PSP; N=24), schizophrenia (SCZ; N=21), a young control group (YCG; N=22) and an aged control group (ACG; N=53). Amongst these 18 common neurological conditions and controls we report a statistically significant trend for aluminum to be increased only in AD, DS and DDS compared to age- and gender-matched brains from the same anatomical region. The results continue to suggest that aluminum’s association with AD, DDS and DS brain tissues may contribute to the neuropathology of these neurological diseases but appear not to be a significant factor in other common disorders of the human central nervous system (CNS).

Multiple response optimization of sequential speciation of chromium in water samples by in situ solvent formation dispersive liquid–liquid microextraction prior to electrothermal atomic absorption spectrometry determination

A sensitive and selective in situ solvent formation dispersive liquid–liquid microextraction (in situ DLLME) method followed by electrothermal atomic absorption spectrophotometry for sequential extraction and determination of trace level of chromium (Cr) species was developed. The preconcentration and extraction of Cr species were carried out using ammonium pyrrolidine dithiocarbamate as a chelating agent, and a water-immiscible ionic liquid based on in situ solvent formation as an extraction solvent. Various operating variables such as sample pH, the KPF6 amount and the ionic liquid volume on the extraction efficiency responses (EE%) of Cr(III) and Cr(VI) ions were investigated. Response surface methodology using central composite design was employed for modeling of the responses. Multi-response optimization with desirability function (DF) approach has been used to maximize EE% one Cr species in the presence of another species. After this step, DF was employed to optimize the variables to define the best extraction conditions for Cr speciation. Under the optimal extraction conditions, the calibration curves were linear in the concentration ranges of 20–200 ng L−1 for Cr(III) and 70–250 ng L−1 for Cr(VI) with the limit of detections of 3.7 ng L−1 for Cr(III) and 2.13 ng L−1 for Cr(VI). The relative standard deviations of five microextractions of 100 ng L−1 Cr(III) and Cr(VI) were 9.07 % and 2.39 %, respectively. Finally, the developed method was applied to the determination of Cr(III) and Cr(VI) ions in real water samples.

Combining multivariate analysis and human risk indices for assessing heavy metal contents in muscle tissues of commercially fish from Southern Red Sea, Saudi Arabia.

Jizan fishers are the major fish source for more than 1.5 million populations in the southern region in Saudi Arabia. Despite the overgrowing of various man-made activities in Jizan City, no recent study on environmental monitoring was reported. In the current study, heavy metals were quantified in muscle tissues of 12 fish species, as the most edible, from Jizan fisheries. Electrothermal atomic absorption spectrophotometry was used for quantification after microwave wet digestion. Acceptable recovery values (83.46-97.48%) for spiked fish samples with standard solutions were obtained. The following wide ranges of heavy metal concentrations (μg/g, wet weight) in studied fish species were recorded: V (0.004-0.561), Cr (0.013-0.477), Mn (0.073-0.128), As (0.002-0.935), Se (0.083-3.058), Sn (2.835-5.540), and Pb (0.150-0.386). Comparing with international permissible limits, lower levels were recorded in the current study. For total metal accumulation, the relationship between species was examined by cluster analysis, which showed that Epinephelinae was the farthest species from others. The principal component analysis shows one component indicating normal distribution of heavy metals in fish species. Different metal pollution indices (1.35-0.30), which shows the distribution of the total heavy metal concentrations in each species, were recorded. The hazard indices for muscle consumption were less than 1.0 for all studied metals at both ingestion rates except Sn which showed a marginal value of 28.9.

Optimisation of Direct Copper Determination in Human Breast Milk Without Digestion by Zeeman Graphite Furnace Atomic Absorption Spectrophotometry with Two Chemical Modifiers.

Milk is an important food in the human diet, and copper (Cu) in human milk is indispensable to children's normal growth and development. It is consequently important that Cu deficiency, occurring in malnourished women or in malabsorption following bariatric surgery, be prevented. The objective of this work is to provide hospital-based paediatricians with a tool enabling rapid measurement of Cu in human breast milk through a technique that biology laboratories can easily apply. Using electrothermal atomic absorption spectrophotometry with Zeeman correction, we have optimized this method with two chemical modifiers and without digestion for analytical procedure. Detection limits and quantification limits for Cu in human milk were found to be 0.077 and 0.26 μmol/L, respectively. Within-run (n = 30) and between-run (n = 15) variations in a pool of human milk samples were 1.50 and 3.62%, respectively. Average recoveries ranged from 98.67 to 100.61%. The reliability of this method was also confirmed by analysing certified reference material (10%). In breast milk samples collected from 100 lactating mothers, Cu mean (±1 SD) was 7.09 ± 1.60 μmol/L. In conclusion, with minimal preparation and quick determination, the method proposed is suitable for measurement of Cu in human breast milk.

Correlation of aluminum and manganese concentration in scalp hair samples of patients having neurological disorders.

Neurodegenerative diseases are thought to be multifactorial, while metals (aluminum and manganese) can be involved as cofactors in abnormalities or suspected of being risk factors for this disorder. The aim of our study was to assess the aluminum (Al) and manganese (Mn) concentrations in scalp hair samples of 397 patients having different types of neurological disorder diseases. For comparative purpose, scalp hair samples of 201 control subjects does not have any neuro-disorders of same age group (30-60 years) and were selected as referents. The Al and Mn in scalp hair samples were assessed by the electrothermal atomic absorption spectrophotometry after microwave-assisted acid digestion. The validity of methodology was checked by the certified human hair reference material (NCS ZC81002). The results of this study showed that the mean values of Al and Mn were significantly higher in scalp hair samples of all types of neurological disorder patients as compared to controls (p = 0.01-0.001). The high levels of Al and Mn may play a role in the development of neurological disorders. However, further work is suggested to examine the precise correlation between trace elemental level and the degree of disorders in neurological patients.

Evaluation of chromium and manganese in biological samples (scalp hair, blood and urine) of tuberculosis and diarrhea male human immunodeficiency virus patients.

The consequence of trace elements deficiency has been associated with an increased risk of human immunodeficiency virus type 1 (HIV-1) disease progression and mortality. This study examined the association between high concentrations of chromium (Cr) and manganese (Mn) in scalp hair, blood, and urine and opportunistic infections in hospitalized patients with the acquired immune deficiency syndrome (AIDS). The study was performed on 62 male HIV+ patients (HIV-1) from different cities of Pakistan. The patients were divided in two groups according to secondary infections (tuberculosis, diarrhea, or high fever). The biological samples (scalp hair, blood and urine) were collected from AIDS patients, and for comparative study 120 healthy subjects (males) of same age group (31 - 45 years), socio-economic status, localities, and dietary habits were also included. The elements in the biological samples were analyzed by electrothermal atomic absorption spectrophotometry after microwave-assisted acid digestion. The validity and accuracy of the methodology was checked by using certified reference materials (CRMs) and with the values obtained by conventional wet acid digestion method on the same CRMs. The results indicated significantly lower concentrations of Cr and Mn in the biological samples (scalp hair, blood, and urine) of male HIV-1 patients, compared with control subjects. It was observed that the lower levels of these trace elements may be predictors for secondary infections in HIV-1 patients. There was a significant decrease in mean values of Cr and Mn in whole blood and scalp hair, whilst higher concentrations were observed in urine samples of the three groups of AIDS patients as compared to a controlled healthy male group (p < 0.001). Low Cr and Mn levels may be due to increased Cr and Mn losses. These data present guidance to clinicians and other professional investigating deficiencies of Cr and Mn in biological samples of AIDS patients.

The effect of manganese supplementation on its concentrations in blood, hair, and organs of goat kids

The aim of this study was to evaluate the effect of supplementation with an organic form of manganese on its concentration in blood, hair, and organs of goat kids. A total of 27 kids were divided into control and experimental groups on the day of their birth (Day 1). The kids were on mother’s milk only diet until the day of weaning (Day 70). After weaning the kids received pellets at doses 0.3 kg/head/day for next 70 days. The control group received pellets (manganese content 36.7 mg/kg) and the experimental group received pellets with extra manganese addition in the form of manganese proteinate at the amount of 220 mg/kg. Blood samples were taken on days 1, 70, 105, and 140; hair samples on days 1, 70, and 140. At the end of experiment, 7 kids from each group were slaughtered and samples of heart, liver, spleen, pancreas, kidney, muscle, and brain were taken. Manganese concentration was determined from fresh tissues after microwave digestion by electrothermal atomic absorption spectrophotometry. Kids of the experimental group had a significantly higher manganese concentration in the liver (4.90 vs. 3.06 mg/kg), heart (0.47 vs 0.28 mg/kg), kidney (1.29 vs. 0.87 mg/kg), brain (0.33 vs 0.26 mg/kg), and hair (4.25 vs. 3.14 mg/kg) compared to the control group. The manganese concentration in blood was not affected by supplementation. Results of this study indicate that using the mentioned organs and hair for evaluation of the manganese status in an organism is more suitable than the determination of manganese concentration in blood.

Aluminium overload after 5 years in skin biopsy following post-vaccination with subcutaneous pseudolymphoma

Aluminium hydroxide is used as an effective adjuvant in a wide range of vaccines for enhancing immune response to the antigen. The pathogenic role of aluminium hydroxide is now recognized by the presence of chronic fatigue syndrome, macrophagic myofasciitis and subcutaneous pseudolymphoma, linked to intramuscular injection of aluminium hydroxide-containing vaccines. The aim of this study is to verify if the subcutaneous pseudolymphoma observed in this patient in the site of vaccine injection is linked to an aluminium overload. Many years after vaccination, a subcutaneous nodule was discovered in a 45-year-old woman with subcutaneous pseudolymphoma. In skin biopsy at the injection site for vaccines, aluminium (Al) deposits are assessed by Morin stain and quantification of Al is performed by Zeeman Electrothermal Atomic Absorption Spectrophotometry. Morin stain shows Al deposits in the macrophages, and Al assays (in μg/g, dry weight) were 768.10±18 for the patient compared with the two control patients, 5.61±0.59 and 9.13±0.057. Given the pathology of this patient and the high Al concentration in skin biopsy, the authors wish to draw attention when using the Al salts known to be particularly effective as adjuvants in single or repeated vaccinations. The possible release of Al may induce other pathologies ascribed to the well-known toxicity of this metal.

In vitro study of percutaneous absorption of aluminum from antiperspirants through human skin in the Franz™ diffusion cell

Aluminum salts such as aluminum chlorohydrate (ACH) are known for use as an active antiperspirant agent that blocks the secretion of sweat. A local case report of hyperaluminemia in a woman using an aluminum-containing antiperspirant for 4years raises the problem of transdermal absorption of aluminum (Al). Only a very limited number of studies have shown that the skin is an effective barrier to transdermal uptake of Al. In accordance with our analytical procedure, the aim of this study with an in vitro Franz™ diffusion cell was to measure aluminum uptake from three cosmetic formulations of antiperspirant: the base for an “aerosol” (38.5% of ACH), a “roll-on” emulsion (14.5% ACH), and a “stick” (21.2%), by samples of intact and stripped human skin (5 donors). The Al assays were performed by Zeeman Electrothermal Atomic Absorption Spectrophotometry (ZEAAS). Following contacts lasting 6, 12 and 24h, the Al assays showed only insignificant transdermal absorption of Al (≤0.07% of the quantity of Al deposited) and particularly low cutaneous quantities that varied according to the formulations (1.8μg/cm² for “aerosol base” and “stick” — 0.5μg/cm² for the “roll-on”). On stripped skin, for which only the “stick” formulation was tested, the measured uptake was significantly higher (11.50μg/cm² versus 1.81μg/cm² for normal skin). These results offer reassurance as regards to the use of antiperspirants for topical application of ACH-containing cosmetic formulations on healthy skin over a limited time span (24h). On the other hand, high transdermal Al uptake on stripped skin should compel antiperspirant manufacturers to proceed with the utmost caution.

In situ formed 1-hexyl-3-methylimidazolium hexafluorophosphate for dispersive liquid-liquid microextraction of Pd(II) prior to electrothermal AAS and spectrophotometry

1-Hexyl-3-methylimidazolium hexafluorophosphate was prepared in situ and used as extractant in dispersive liquid-liquid microextraction. Ultra-trace amounts of Pd(II) could be accurately determined by electrothermal atomic absorption spectrometry (ETAAS) and spectrophotometry after extraction by the formed micro-droplets of the ionic liquid phase. 1-(2-Pyridylazo)-2-naphthol was used to produce a hydrophobic palladium complex prior to extraction. The effects of concentrations of reagents, reaction and extraction times, and the other parameters were investigated and optimized. Beer's law was obeyed in the ranges of 0.015-0.900 and 1.50-63.0 ng mL^{-1} Pd(II) by ETAAS and spectrophotometry, respectively. Under the optimized conditions, the limit of detection (LOD) by ETAAS was 3 ng L^{-1} with an enrichment factor of 460. The RSD percent was in the range of 1.3%-4.8% for various standard concentrations of Pd(II) in the range of 0.050-40.0 ng mL^{-1}. Most ions did not interfere. The method was successfully applied to the determination of Pd(II) in some water and alloy samples, jewels, and palladium catalysts.

Plasma selenium concentrations in pregnant women in two countries with contrasting soil selenium levels

Project Selenium has an important role in antioxidant defense and cell mediated immunity. Plasma selenium is a useful biomarker for comparing selenium status across populations, and influenced by selenium levels of soils and plants. Procedure This cross-sectional study compared plasma selenium (by electrothermal atomic absorption spectrophotometry) of women at 24 weeks gestation in Malawi ( n = 152) and the Philippines ( n = 301), countries with low and high soil selenium levels, respectively. Data on anthropometry, smoking, intakes of energy, nutrients and food groups (via 24-h recalls), hemoglobin, serum zinc, and C-reactive protein (CRP) were also collected. Results Mean (95% CI) plasma selenium was lower for Malawian than Filipino women (0.79, 0.77, 0.82 μmol/L vs. 1.44, 1.41, 1.47 μmol/L; p < 0.001); 83% had concentrations below 1.0 μmol/L compared to 3% in the Filipinos. Cereals provided 78% and 67% of the energy in Malawi and the Philippines, respectively compared to 4% and 8.5%, respectively for cellular animal protein. Plasma selenium was correlated modestly with BMI ( r = −0.138; p = 0.096) and elevated CRP (>5.0 mg/L) ( r = −0.143; p = 0.084) in Malawi, and significantly with intake of cellular animal protein (g/d) ( r = 0.23; p = 0.020) and serum zinc ( r = 0.13; p = 0.044) in the Philippines. No comparable relationships were observed in either group for smoking, hemoglobin, or cereal intakes. Conclusion Differences in plasma selenium paralleled reported trends in selenium concentrations in soils and staple cereals in Malawi and the Philippines. The biological significance of the lower plasma selenium for the Malawian women, and the extent to which they pose a risk for fetal and neonatal development, is uncertain.

Effects of supplementing dairy cows with chromium propionate on milk and tissue chromium concentrations

Eight primiparous and 8 multiparous Holstein cows were used to determine the effects of Cr supplementation, in the form of Cr propionate (Cr Prop), on milk and tissue Cr concentrations. Cows were randomly assigned by parity to one of 2 diets: 1) control diet or 2) 2mg of supplemental Cr/kg of DM. The level of Cr Prop supplemented exceeded by 4-fold the concentration of 0.5mg of Cr/kg permitted by the FDA. Experimental diets were fed from approximately 30 d prepartum until at least 91 d postpartum, resulting in a minimum of 121 d of exposure to supplemental Cr. The control prepartum and postpartum diets analyzed 0.48 and 0.38mg of Cr/kg of DM, respectively. Milk samples were obtained from the a.m. milking on d 0 (colostrum), 7, 14, 21, 28, 42, 56, 77, and 90 and on the final day of the study for Cr analysis. Cows were harvested after lactating for a minimum of 91 d and samples of liver, kidney, semitendinosus muscle, and fat were obtained for Cr analysis. Chromium was measured using electrothermal atomic absorption spectrophotometry. Milk Cr concentration averaged 1.7 ng/mL and was affected by day of lactation but not by Cr or a Cr × day interaction. Supplementation of 2mg of Cr/kg of DM increased kidney Cr by approximately 3-fold and liver Cr concentrations by approximately 2-fold. Chromium concentrations in muscle and fat were not affected by Cr supplementation. In summary, supplementation of Cr Prop at a level of 2mg of Cr/kg of DM did not affect Cr concentration in milk, muscle, or fat, the major bovine products consumed by humans.

Direct Arsenic Determination in Exposed Embryos of Zebrafish (Danio rerio) with Zeeman Electrothermal Atomic Absorption Spectrophotometry

ABSTRACT Several methods of analysis have been evaluated for the determination of the arsenic content in zebrafish embryos (Danio rerio). The methods have been developed based on waste minimization, while sample treatment was exploited to attend the standards of clean chemistry. The ultimate goal of developing a method to directly introduce whole single embryos into the electrothermal furnace atomic absorption spectrometer (ETAAS) was accomplished after optimization of instrument parameters and matrix modifiers. The significant matrix effects due to the complexity of the sample were overcome by the use of a palladium modifier and hydrogen peroxide as an oxidizing agent to aid in the mineralization of the sample during the pyrolysis. The results obtained from this direct method for arsenic analysis were in agreement with those from more common sample preparation methods of acid digestion or ultrasonic extraction. The speed of the ultrasonic method and use of environmentally safe reagents makes this a more favorable technique than acid digestion. The single embryo direct introduction method, however, is preferred due to its ability to measure whole single samples without any sample pretreatment, and furthermore allows for evaluation of the variability of arsenic accumulation between individual samples. The ETAAS method developed has been validated by inductively coupled plasma mass spectrometry (ICP-MS).

Evaluation of Toxic Elements in Scalp Hair Samples of Myocardial Infarction Patients at Different Stages as Related to Controls

In the present study, the association of arsenic, cadmium, lead, and nickel between scalp hair samples and mortality from myocardial infarction (MI) patients at first, second, and third heart attack was studied. The biological samples of 130 MI patients (77 male and 53 female) age ranged (45-60 years), were collected and 61 healthy persons of same age group (33 male and 28 female) was selected as control subjects. The toxic elements (TEs) in biological samples were assessed by the electrothermal atomic absorption spectrophotometry prior to microwave-assisted acid digestion. The validity of methodology was checked by the certified human hair reference material (BCR 397). It was observed during the study that 78% of 32 patients of the third MI, age >50 years were expired. In these subjects, the level of As, Cd, Ni, and Pb were increased by 10.6%, 19.5%, 15.7%, and 9.8% in the scalp hair as compared to those who tolerated third MI attack (p = 0.12). The high level of toxic metals may play a role in the development of heart disease in the subjects of this study.

Erythrocytes Constitute the Main Blood Compartment for Aluminum

Aluminum (Al), a trace metal with no biological function and toxic to humans and animals, is associated with hematological/metabolic alterations and neurodegenerative processes such as Alzheimer's disease (AD). Further evidence supports Al's role in the etiology of AD and validates use of readily accessible tissues such as peripheral blood. Basal Al concentration has been reported in plasma and serum, while studies in erythrocytes are scant. Here, we report optimal conditions for simultaneous determination of Al concentration in blood compartments from humans and sheep. Al was determined by electrothermal atomic absorption spectrophotometry in whole blood, plasma, serum and red blood cells (RBCs). Solvent type and composition, matrix modifier concentration and sample age were tested on the reproducibility of Al determination. Significant interindividual variability was observed in human blood samples in the different components possibly due to the inclusion of healthy donors and patients with AD in a single group. RBCs had larger variability in Al concentration and values were affected by the solvent used. The Al concentration in RBCs, plasma and serum was 70%, 30% and 25% of the total blood, indicating that RBCs constitute the major compartment for Al. Simultaneous determination of Al in all blood components under optimal conditions may help to clarify this biological toxin's role in degenerative diseases.