Atomic Absorption Flame Photometry Research Articles

Abstract P228: Relationships of Dietary and Supplement Magnesium Intake and Its Urinary Metabolomic Biomarkers With Blood Pressure: The INTERMAP Study

Background: Magnesium (Mg) and other mineral intakes are vital contributors to a healthy diet and appear to have a modest effect on the risk of hypertension. Studies suggest that supplemental Mg can significantly lower blood pressure (BP). Here, we investigate associations of total Mg consumption with the level of its urinary metabolomic biomarkers, and BP. Method: We used cross-sectional data from the International Study of Macro-/Micronutrients and Blood Pressure (INTERMAP) on 4269 men and women aged 40-59 years from Japan, China, United Kingdom, and United States (US). Regression coefficients with BP per 2 standard deviation (SD) higher dietary Mg from food plus supplement (obtained from 24-hr dietary recalls), urinary Mg (measured by atomic absorption flame photometry) and small molecules (analysed by direct injection mass spectrometry) were estimated using multivariable models, adjusted for age, gender, population sample, intake of total energy and other confounders (see Table). To estimate overall association, country-specific regression coefficients were pooled, weighted by inverse of their variance. Results: Average Mg intakes were 454 (SD=207) mg/day for 770 persons who reported Mg supplementation (89% from US), and 300 (SD=101) mg/day for those who did not. High correlation was found between Mg intake from food plus supplements with urinary Mg ( r =0.38, P<0.0001). Partial correlations of small molecules with total Mg intake ranged from -0.007 to 0.19 for ascorbic acid (P<0.0001). Total Mg intake higher by 261.87 mg/day (2SD) was associated with a systolic BP difference of -2.65 mm Hg ( P =6x10 -5 ). Urinary Mg excretion higher by 2.66 mmol/day was associated with a diastolic BP difference of -1.02 mm Hg (P=0.02). There was a non-significant inversed association between ascorbic acid and BP in some multivariable regression models. Conclusion: Higher intake of Mg, including supplements, was associated with lower BP levels.

Heavy metal concentrations in water, sediment and periwinkle ( Tympanotonus fuscastus ) samples harvested from the Niger Delta region of Nigeria

Heavy metal pollution of terrestrial and aquatic environments in Niger-delta region of Nigeria is on the increase due to increased urbanization and crude oil exploration. Tympanotonus fuscastus are mud dwellers and could bioaccumulate heavy metals; therefore consumption of heavy metal contaminated sea foods like periwinkle may breed lots of health problems. Heavy metal concentration in water, sediment and Periwinkle samples from three locations (Itu-River, Abuloma River and Oron River) in the Niger Delta Region of Nigeria were evaluated using atomic absorption flame photometry. Result showed that cadmium (Cd) concentration was highest in water samples from Abuloma River (0.106 mg/l) while lead (Pb) concentration was highest (0.01mg/l) in the water samples from Itu River. Cd and Pb concentrations (0.127 and 0.08 mg/kg, respectively) in sediment samples were highest in Abuloma River. The concentration of Cd in T. fuscastus samples was 0.11 mg/kg in Abuloma River, while concentration was 0.27 mg/kg in Oron River. Copper (Cu) was generally low in the water samples; the highest concentration (0.011 mg/kg) was obtained in water samples from Oron River. Sediment concentration of Cu was high (0.088 mg/kg) in Itu River, while its concentration in the periwinkle samples was 0.54 mg/kg in Abuloma River. The results also showed that Cr, As and Hg were below detectable concentration in tissues, soil and water samples from Itu and Abuloma Rivers, while Hg concentration in Oron River sediment was 64.2 mg/kg. Key words : Sea foods, heavy metals, pollution, environment, nutrition, bioaccumulation

Heavy metal concentrations in water, sediment and periwinkle (Tympanotonus fuscastus) samples harvested from the Niger Delta region of Nigeria

Heavy metal pollution of terrestrial and aquatic environments in Niger-delta region of Nigeria is on the increase due to increased urbanization and crude oil exploration. Tympanotonus fuscastus are mud dwellers and could bioaccumulate heavy metals; therefore consumption of heavy metal contaminated sea foods like periwinkle may breed lots of health problems. Heavy metal concentration in water, sediment and Periwinkle samples from three locations (Itu-River, Abuloma River and Oron River) in the Niger Delta Region of Nigeria were evaluated using atomic absorption flame photometry. Result showed that cadmium (Cd) concentration was highest in water samples from Abuloma River (0.106 mg/l) while lead (Pb) concentration was highest (0.01mg/l) in the water samples from Itu River. Cd and Pb concentrations (0.127 and 0.08 mg/kg, respectively) in sediment samples were highest in Abuloma River. The concentration of Cd in T. fuscastus samples was 0.11 mg/kg in Abuloma River, while concentration was 0.27 mg/kg in Oron River. Copper (Cu) was generally low in the water samples; the highest concentration (0.011 mg/kg) was obtained in water samples from Oron River. Sediment concentration of Cu was high (0.088 mg/kg) in Itu River, while its concentration in the periwinkle samples was 0.54 mg/kg in Abuloma River. The results also showed that Cr, As and Hg were below detectable concentration in tissues, soil and water samples from Itu and Abuloma Rivers, while Hg concentration in Oron River sediment was 64.2 mg/kg. Key words: Sea foods, heavy metals, pollution, environment, nutrition, bioaccumulation

Vasculopathy in type 2 diabetes mellitus: role of specific angiogenic modulators

Type 2 diabetes mellitus (T2DM) is largely defined by hyperglycemia that promotes vascular complications. Abnormal angiogenesis has been claimed to have a role in this disease. This study aimed to investigate serum levels of both conventional and other markers of angiogenesis not well studied before in diabetes, and to correlate findings with age of the patients, glycemic control, presence of microvascular complications, and oxidative stress. Thirty-eight patients with T2DM and 13 age- and sex-matched healthy persons representing controls were recruited. Serum levels of basic fibroblast growth factor (b-FGF) was measured by immunosorbent assay kit; advanced glycosylation end products, platelet-derived endothelial cell growth factor (PD-ECGF), cathepsin-D (CD), gangliosides, hyaluronic acid (HA), nitric oxide (NO), lipid peroxides (LPER), superoxide dismutase, and total thiols by chemical methods; and copper (Cu) by atomic absorption flame photometry. Advanced glycosylation end products and angiogenic factors (b-FGF, PD-ECGF, CD, gangliosides, HA, and Cu) were significantly higher in patients than controls. Oxidative stress markers, NO, and LPER were significantly higher while total thiols were significantly lower in patients than controls. These changes were more pronounced with age, poor glycemic control, and presence of microvascular complications. Angiogenesis dysfunction coinciding with elevated levels of many angiogenic growth factors may point to their malfunctioning due to oxidative stress and/or protein glycation at the factor and the receptor levels. This necessitates further investigations.

Temperature dependence of density of polymer gels: Effects of ionizable groups in copoly(N-isopropylacrylamide/acrylic acid or sodium acrylate)–water systems

Effects of ionizable groups in hydrogels of copolymer networks on the volumetric contraction–expansion process were investigated. Polymer networks used were: copoly[N-isopropylacrylamide (NIPA)(1−x)/acrylic acid (HAc) or sodium acrylate (NaAc)(x)] with mole fraction of minor component (x) assuming 0.0114 and 0.0457. From the temperature (T) dependence of total volume of gels, densities of the polymer and solvent (water) components, and stoichiometry, we evaluated (1) the volume of gels occupied by a single mean polymeric residue and associated water molecules (expressed in units of nm3), mean vsp(gel), and (2) number of water molecules per single mean polymeric residue, mean Ns(gel), from near 273K to 323K. These quantities (1) and (2) listed above showed how acid and salt forms affect differently on volumetric changes of gels over 50K. We developed an approach to evaluate volumetric changes of gels solely caused by a single polymeric residue of a minor component (x<0.05) plus associated water by applying thermodynamic first-order perturbation theory. They are specific vsp(gel)(T) for a single HAc or NaAc polymeric residue plus associated water and the corresponding specific Ns(gel)(T). Specific vsp(gel)(HAc or NaAc)(T) and the corresponding specific Ns(gel(T)) revealed specific characteristics in thermal behavior near their respective transition temperatures from the swollen to shrunken states. We found these thermal changes shown at the nano-scale match very well with specific changes in the molality(T) of both ionizable groups. In fact, these are directly triggered by varying contents of water in gels. Based on the understanding of dissociative equilibrium attained by ionizable groups, we successfully replaced Na+ in hydrogels of copoly[NIPA(1−x)/NaAc(x)] (x=0.0457) by hydrogen ions. Absence of Na+ in treated hydrogels was experimentally verified by 23Na NMR and Na atomic absorption flame photometry. Discontinuity in the volumetric contraction–expansion process from the swollen to shrunken states and vice versa was not observed in contradiction to the previous reports [Hirotsu S, Hirokawa Y, Tanaka T. J Chem Phys 1987;87:1392–5. Matsuo SE, Tanaka T. J Chem Phys 1988;89:1695–703.] obtained by the conventional swelling experiments.

Removal of Some Heavy Metal Cations from Aqueous Solution by Adsorption onto Natural Kaolin

The adsorption removal of some heavy metal cations such as Cu(II), Zn(II) and Co(II) from aqueous solution onto kaolin has been studied using the batch method with initial metal ion concentrations within the range 15–70 mg/l. The percentage adsorption and equilibrium concentrations were determined by means of atomic absorption flame photometry as a function of adsorbate concentration, pH and temperature. Ion-exchange studies showed that over the complete concentration range studied the adsorption ratios for metal cations adsorbed onto kaolin correlated with the linear forms of the Langmuir, Freundlich and Dubinin—Kaganer—Radushkevich (DKR) adsorption isotherms. The cationexchange capacity of kaolin towards each metal ion studied was evaluated. It was found that the adsorption phenomena depended on the charge density and diameter of the hydrated ion. The equilibrium studies demonstrated that the selectivity of the ions followed the sequence Zn(II) &gt; Cu(II) &gt; Co(II) at pH 7.0. Calculation of thermodynamic parameters such as the standard enthalpy (ΔH0), Gibbs free energy (ΔG0) and entropy (ΔS0) showed that the adsorption of the heavy metal ions studied onto kaolin was an endothermic process which was favoured at higher temperatures. These results show that natural kaolin has a considerable potential for the removal of heavy metal cationic species from aqueous solution and wastewater.

Modifications of Intracellular Calcium Release Channels and Calcium Mobilization Following 70% Hepatectomy

The aim of this study was to investigate the properties of ryanodine and IP3receptors in regenerating liver following 70% hepatectomy, and to evaluate the hepatic Ca2+distribution and mobilization during this process. Specific [3H]ryanodine and [3H]IP3binding to hepatic smooth endoplasmic reticulum membranes, as well as subcellular Ca2+determination by atomic absorption flame photometry and Ca2+mobilization by INDO-1 AM spectrofluorescence in hepatocytes, was performed in regenerating livers after surgical 70% hepatectomy. Incorporation of14C amino acids into proteins and of32P into phospholipids was done in subcellular fractions. Ryanodine receptorKdpresented a dramatic increase after 12 h of surgery and remained high up to 2 days of treatment. IP3receptorBmaxshowed a significant augmentation starting at 6 h after hepatectomy and returning to normal values after 1 week. Cytosolic total calcium content decreased from 12 h until 4 days after hepatectomy whereas the microsomal and mitochondrial total calcium increased at 1 and 2–4 days of liver regeneration, which coincided with the differential turnover of proteins and phospholipids in these fractions. ATP-induced Ca2+transients in hepatocytes of 24-h-hepatectomized rats confirmed the altered sensitivity of the ryanodine receptor toward its ligand, since 10 times more ryanodine was necessary to alter the ATP-induced Ca2+transient. The data support the notion that the calcium release channels are targets of mechanisms of metabolic control during the proliferative response following 70% hepatectomy and might be part of the modified intracellular Ca2+dynamics during liver regeneration.

Metabolic control of the K+ channel of human red cells

The effects of cAMP, ATP and GTP on the Ca2(+)-dependent K+ channel of fresh (1-2 days) or cold-stored (28-36 days) human red cells were studied using atomic absorption flame photometry of Ca2(+)-EGTA loaded ghosts which had been resealed to monovalent cations in dextran solution. When high-K+ ghosts were incubated in an isotonic Na+ medium, the rate constant of Ca2(+)-dependent K+ efflux was reduced by a half on increasing the theophylline concentration to 40 mM. This effect was observed in ghosts from both fresh and stored cells, but only if they were previously loaded with ATP. The inhibition was more marked when Mg2+ was added together with ATP, and it was abolished by raising free Ca2+ to the micromolar level. Like theophylline, isobutyl methylxanthine (10 mM) also affected K+ efflux. cAMP (0.2-0.5 mM), added both internally and externally (as free salt, dibutyryl or bromide derivatives), had no significant effect on K+ loss when the ghost free-Ca2+ level was below 1 microM, but it was slightly inhibitory at higher concentrations. The combined presence of cAMP (0.2 mM) plus either theophylline (10 mM), or isobutyl methylxanthine (0.5 mM), was more effective than cAMP alone. This inhibition showed a strict requirement for ATP plus Mg2+ and it was not overcome by raising internal Ca2+. Ghosts from stored cells seemed more sensitive than those from fresh cells, to the combined action of cAMP and methylxanthines. Loading ATP into ghosts from fresh or stored cells markedly decreased K+ loss. Although this effect was observed in the absence of added Mg2+ (0.5 mM EDTA present), it was potentiated upon adding 2 mM Mg2+. The K+ efflux from ATP-loaded ghosts was not altered by dithio-bis-nitrobenzoic acid (10 mM) or acridine orange (100 microM), while it was increased two- to fourfold by incubating with MgF2 (10 mM), or MgF2 (10 mM) + theophylline (40 mM), respectively. By contrast, a marked efflux reduction was obtained by incorporating 0.5 mM GTP into ATP-containing ghosts. The degree of phosphorylation obtained by incubating membranes with (gamma-32P)ATP under various conditions affecting K+ channel activity, was in direct correspondence to their effect on K+ efflux. The results suggest that the K+ channel of red cells is under complex metabolic control, via cAMP-mediated and nonmediated mechanisms, some which require ATP and presumably, involve phosphorylation of the channel proteins.

An auxiliary table for concentration calculations in atomic-absorption flame photometry

A table has been prepared for atomic-absorption work which gives concentrations in ppm and percent of analyte in original sample for a given series of standards as a function of the dilution ratio used during the steps of sample preparation. The use of original concentrations simplifies the calculation of concentration in manual graphical interpolation and allows the operator the use of simple interpolation computer programs, if desired, without the need of introducing constant or variable conversion factors. The table covers the most frequent concentration ranges of minor and micro components and dilution ratios from 1:10 to 1:10000.

Comparison of the sensitivity of atomic-fluorescence and atomic-absorption flame photometry

Comparison of the sensitivity of atomic-fluorescence and atomic-absorption flame photometry

The dilution process in sample preparation for atomic-absorption flame photometry

Summary A graph is presented and discussed to assist in choosing the appropriate dilutions for original samples in atomic-absorption flame photometry. It is based on the percentual sensitivity obtained with a given instrumental system. The additive properties of log-log scales permit even further simplifications of the scheme. The graph is also shown to be useful in choosing single dilutions for multielement analysis with analytes having different percentual sensitivities.

Chemico-analytical selectivity and sensitivity in atomic-absorption flame photometry

Summary Practical applications of atomic-absorption flame photometry should be established on the basis of the attainable analytical characteristics of the method both from the instrumental and chemical point of view. Main characteristics involved are sensitivity, selectivity, accuracy, and precision. The first two are discussed in this contributon. Sensitivity and selectivity depend on the analytical system (analyte or analytes, and concomitant components, i.e., chemical composition of the system subject to analytical determinations) and on the instrumental system. Factors involved are discussed and illustrated with examples based on experimental data. Lack of chemical and/or instrumental selectivity immediately affects sensitivity. Sensitivity changes can disturb accuracy and precision in determinations. In order to avoid this situation some operational ways of increasing selectivity are described and are correlated with effects in atomic-absorption sensitivity.

Relationship between sensitivity and precision in atomic-absorption flame photometry

Summary Precision results, standard deviation or relative standard deviation, can be expressed in terms of either reading or analyte concentrations. The latter is perhaps more useful when expressing analytical data, but both are based on instrumental readings obtained with the measuring instrument. An important consideration is the quality of the signal itself (signal size and noise level). Signal size for a given concentration is directly correlated with the corresponding percentual sensitivity obtained under the chosen working conditions. Signal noise, also for a given concentration, is in turn directly correlated with the values known as fluctuational sensitivities. Three main cases are considered here: (a) small signal size , (b) medium signal size , and (c) large signal size . At low signal size two effects have been observed which can impair precision: (a) fluctuations of signal size due to residual effects, memory and similar forces; and (b) fluctuations of zero adjustment.

The concentration process in sample preparation for atomic-absorption flame photometry

Summary A graphical representation can be used for choosing the appropriate preliminary concentration factors in preparing samples for atomic-absorption flame photometric determinations. The graph has been constructed on the basis of the percentual sensitivity obtained with a given instrumental system. The graph can be further simplified for practical applications. The use of the graph can also be extended to multielement concentrating extractions.

High sodium systems in atomic absorption flame photometry

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHigh sodium systems in atomic absorption flame photometryJuan. Ramirez-MunozCite this: Anal. Chem. 1970, 42, 4, 517–518Publication Date (Print):April 1, 1970Publication History Published online1 May 2002Published inissue 1 April 1970https://doi.org/10.1021/ac60286a029RIGHTS & PERMISSIONSArticle Views82Altmetric-Citations8LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (260 KB) Get e-Alerts Get e-Alerts

Slide-rule for atomic-absorption flame photometry

A new slide-rule is described for calculations in the field of atomic-absorption flame photometry. Most of the quantities used in analytical applications and in studies on the analytical behaviour of determinants are included in the operations which may be performed with the slide-rule. It can also be used for the most common operations necessary for calculation of concentrations, dilutions, dilution ratios and analytical factors. The rule described quickens calculation and reduces use of conversion tables.

Reconsideration of the Criteria to Determine Practical Fluctuational Concentration Limits in Atomic-Absorption Flame Photometry

A study is presented on the influence of the instrumental time constant value in the determination of fluctuational sensitivity in atomic-absorption flame photometry. Fluctuational concentration limit (detection limit) has been defined as a function of the noise level of the blank reading (blank adjusted at the 0% absorption level), while the signal noise is a direct function of the time constant of the readout system employed. Employing a Beckman 979 atomic-absorption system and recorder, a scale expander unit was modified to provide a time constant control. The behavior of several elements is presented as an example of the dependence of the fluctuational concentration limit on the system time constant. These results, clearly indicating a basic relationship, lead to the establishment and presentation of a new criterion in an attempt to define and to compare concentration limits of a fluctuational nature.

Recent Results with a Nitrous Oxide—Acetylene Burner in Atomic-Absorption Flame Photometry

Performance data are presented for several elements determined by atomic-absorption flame photometry with the use of a high sensitivity nitrous oxide—acetylene burner. Utilizing the specific advantages of this flame, the effect of gas mixtures, feeding rate, and the height of reaction zone on the sensitivities achieved are presented. Flame profiles of several elements studied will be discussed with emphasis on using multiple-pass optics for increased sensitivities. Information will be presented on the problems of this type of flame. Results are presented in terms of the precision and accuracy of routine determinations under selected optimum system conditions and will be discussed.

Applications of sensitivity diagrams to atomic-absorption flame photometry

Sensitivity diagrams have been applied to atomic-absorption work, in the form of plane and space diagrams. These diagrams facilitate the representation and comparison of the analytical behaviour of different elements in terms of percentual and fluctuational sensitivity. They also aid in the study of single elements under diverse experimental conditions or with different instruments. Space diagrams permit the representation and study of variations of sensitivity in the presence of one or more masking agents under the same or differing experimental conditions. Limiting interference ratios can easily be calculated with the help of diagrams of this type.

Determination of Some Trace Elements in Two Different Limestones by Atomic Absorption Flame Photometry

Perhaps the most monumental work on the analysis of eastern Kansas limestones, was done by Russel T. Runnels and co-workers (9). Their work and most other work, was done on composite samples (channel analysis). Until recently (6, 7) little or no work appears to have been done on the vertical variations in the chemical composition within a unit of limestone. The purpose of this study was to determine whether or not there is a difference in the vertical deposition of some trace elements in limestone in going from the bottom to the top of the bed. The elements studied to this time, are copper, chromium, nickel, vanadium, strontium, molybdenum and zinc. One of the two limestones studied was the Cottonwood Limestone bed, member of the Beattie Formation of the Permian System. This limestone bed consists of a ledge 5 to 7 feet thick and has at least three distinct layers. The top and bottom layer are approximately 3 feet in thickness and the center layer around 4 inches in thickness. The second limestone chosen for this work was the Burr Limestone, member of the Grenola Formation of the Permian System. This limestone ledge is also in three distinct layers with a total thickness of around 6 to 7 feet. The top and bottom layer are of approximately equal thickness of 3 feet. The center layer is about 1 foot in thickness and consists of shale, rather than limestone.