Multivariate optimization of a goat meat alkaline solubilization procedure using tetramethylammonium hydroxide for metals determination using FAAS.

In the present work, multivariate designs were used to optimize an alkaline dissolution, assisted by ultrasound energy, procedure of goat meat using tetramethylammonium hydroxide (TMAH) aiming to determine Ca, Cu, Fe, K, Mg, Na and Zn by flame atomic absorption (FAAS) and emission (FAES) spectrometry. The optimal conditions found for the dissolution were in the following ranges: 0.4-0.5 g for the sample mass, 12-15 min of sonication and using 700-1000 µL of 25% TMAH at a temperature of 50 °C. The obtained limits of quantification varied between 0.221 (Mg) and 7.60 (Ca) µg g-1. Accuracy was assessed by comparing the results obtained by applying the proposed method with the digestion in an acid medium using a digesting block and by analyzing bovine liver certified reference material. The application of a t-test revealed that, at a 95% confidence level, there were no significant differences between the values obtained.

Cloud point extraction combined with graphite furnace atomic absorption spectrometry for speciation of Cr(III) in human serum samples.

A cloud point extraction (CPE) method for the preconcentration of ultra-trace chromium speciation in human serum samples prior to determination by graphite furnace atomic absorption spectrometry (GFAAS) had been developed in this paper. In this method, Cr(III) reacts with 1-(2-pyridylazo)-2-naphthol (PAN) yielding a hydrophobic complex, which is then entrapped in the surfactant-rich phase, whereas Cr(VI) remained in aqueous phase. Thus, separation of Cr(III) and Cr(VI) could be realized. Total chromium was determined after the reduction of Cr(VI) to Cr(III) by using ascorbic acid as reducing reagent. PAN was used not only as chelating reagent in CPE, but also as chemical modifier in GFAAS. Triton X-114 non-ionic surfactant had been used as an extraction medium. The main factors affecting CPE efficiency, such as pH of solution, concentration and kind of complexing agent, concentration of non-ionic surfactant, equilibration temperature and time, were investigated in detail. An enrichment factor of 83.5 was obtained for the preconcentration of Cr(III) with 10 mL solution. Under the optimal conditions, the detection limit of Cr(III) was 0.02 µg L⁻¹. The relative standard deviation was 2.6% for intra-day assay precision (n=7, c=10 ng mL⁻¹), values of recovery for chromium were from 92.0% to 94.7% for three samples. This method is simple, accurate, and sensitive and can be applied to determine ultra-trace chromium speciation in human serum.

Gold-nanoparticle-based graphite furnace atomic absorption spectrometry amplification and magnetic separation method for sensitive detection of mercuric ions.

We have developed a sensitive gold-nanoparticle-based (AuNP-based) graphite furnace atomic absorption spectrometry (GFAAS) amplification and magnetic separation method for the detection of mercuric ions (Hg²âº). The assay relies on (i) a sandwich-type structure containing two thymine-thymine (T-T) mismatches for selectively recognizing Hg²âº ions; (ii) magnetic beads for homogeneous separation; and (iii) AuNP-based GFAAS amplification detection. The limit of detection (LOD) of this assay is 0.45 nM (0.09 µg L⁻¹)--one order of magnitude lower than the United States Environmental Protection Agency (US EPA) limit for Hg²âº in drinking water. Furthermore, because a shorter hybridization step and a simpler AuNP-based GFAAS amplification detection were employed, a faster analytical run time allowing us to analyze a batch of 24 samples within 0.5 h. We demonstrated the feasibility of the developed approach for the determination of Hg²âº in urine and aqueous environmental samples.

Evaluation of phosphorus, protein, and n-3 fatty-acid content in 15 marine fish species identifies the species most beneficial to renal patients.

OBJECTIVE: Among 15 marine fish species, we sought to identify those most beneficial to renal patients by evaluating their phosphorus (P), protein (PC), and n-3 fatty-acid (n-3 PUFA) content. DESIGN: These 15 species are all edible. They were obtained and sampled randomly, and were filleted to obtain 100g, enabling us to perform the analysis in triplicate. Crude protein was analyzed with a Kjeltec, and minerals were analyzed using atomic absorption spectrophotometry. RESULTS: The PC values (g/100g) ranged from 14.3 (blue runner; BR) to 22.8 (California butterfly ray). The fish with the highest P (mg/100g) content were spotted sea trout (ST), gafftopsail fish (CF) (289), and BR (274), followed by smalltail shark (272). The species with the lowest ratio of P:n-3 PUFA was dollar fish (DF) (0.28), followed by BR, ST, and vermilion snapper (range, 0.28 to 0.67). The highest ratio of P:n-3 PUFA was found in the small-tail shark (11.6). Fish with a high n-3 PUFA/g PC content were DF (41.7), BR (38.05), ST (34.8), and CF (22.5). There was a tendency of P to increase as muscle fat increased (mg P/100g), i.e., lean fish (194), semifatty fish (239), and fatty fish (262). CONCLUSIONS: The regular inclusion in the diet, at least three times a week, of the species DF, BR, CF, ST, caitipa mojarra, vermillion snapper, and pot snapper can be considered beneficial to the general health status of renal patients.

Determination of ultratrace amounts of Ce3+ in the presence of Sm3+, La3+, Dy3+, and Yb3+ in water and soils by inductively coupled plasma-optical emission spectroscopy after preconcentration with thio-functionalized MCM-41 at controlled pH.

A method is presented for the selective preconcentration and determination of ultratrace amounts of Ce3+ ions by inductively coupled plasma-optical emission spectroscopy in the presence of Sm3+, La3+, Dy3+, Yb3+, and common interfering ions. In this method, thio-functionalized MCM-41 is used in the preconcentration step. Extraction efficiency and the influence of sample matrix, pH of sample solution, type and minimum amount of tripping acid, and flow rates were investigated. The preconcentration is pH-dependent, and the best results were obtained in the pH range of 8.5-10.3. The maximum capacity of 2 mg absorbent was found to be 170 +/- 4 microg. The detection limit of the measurements after the preconcentration step was found to be 114 ng Ce3+/L.

Determination of trace amounts of nickel, manganese, cobalt, and zinc in environmental samples after separation and preconcentration by use of polyacrylic acid/alumina sorbent.

Manganese, nickel, cobalt, and zinc are elements that appear together in many real samples. In this work, a simple, rapid, and sensitive method has been used for the simultaneous separation and preconcentration of trace amounts of these elements using water-soluble polyacrylic acid on alumina as a sorbent in a glass column system. A solution containing Mn, Ni, Co, and Zn was passed through the column at pH 7, and desorption was carried with 5.0 mL of 0.03 M nitric acid. Linearity was maintained between 0.25-5.0 x 10(3), 0.04-6.0 x 10(3), 0.10-8.0 x 10(3), and 0.028-1.0 x 10(3) ng/mL for Ni, Mn, Co, and Zn, respectively, in the original solution. Eight replicate determinations of a mixture containing 1.0 microg/mL of each of the elements in the final solution gave relative standard deviations of 1.4, 1.5, 2.4, and 1.2% for Ni, Mn, Co, and Zn, respectively. The sorption capacities for Mn (mg/g sorbent) obtained were 16.0 for Mn, 9.0 for Ni, 12.0 for Co, and 10.0 for Zn. By using 5.0 mL elution solution, preconcentration factors of 400, 500, 700, and 460 could be obtained for Ni, Mn, Zn, and Co, respectively.

Standardization and validation of a new atomic absorption spectroscopy technique for determination and quantitation of aluminium adjuvant in immunobiologicals.

In the present study, Aluminium quantification in immunobiologicals has been described using atomic absorption spectroscopy (AAS) technique. The assay was found to be linear in 25-125 microg/ml Aluminium range. The procedure was found to be accurate for different vaccines with recoveries of external additions ranging between 93.26 and 103.41%. The mean Limit of Variation (L.V.) for both intra- and inter-assay precision was calculated to be 1.62 and 2.22%, respectively. Further the procedure was found to be robust in relation to digestion temperature, alteration in acid (HNO(3) and H(2)SO(4)) ratio used for sample digestion and storage of digested vaccine samples up to a period of 15 days. After validation, AAS method was compared for its equivalency with routinely used complexometric titration method. On simultaneously applying on seven different groups of both bacterial and viral vaccines, viz., DPT, DT, TT, Hepatitis-A and B, Antirabies vaccine (cell culture) and tetravalent DPT-Hib, a high degree of positive correlation (+0.85-0.998) among AAS and titration methods was observed. Further AAS method was found to have an edge over complexometric titration method that a group of vaccines, viz., ARV (cell culture, adsorbed) and Hepatitis-A, in which Aluminium estimation is not feasible by pharmacopoeial approved complexometric titration method (possibly due to some interference in the sample matrix), this newly described and validated AAS assay procedure delivered accurate and reproducible results.

Abel inversion applied to a small set of emission data from a microwave plasma.

In this work we propose a criterion to apply the Abel inversion in the case of a small set of experimental data to be used in laboratory plasmas. The Nestor-Olsen method, spline interpolation, and Fourier transform Abel inversion have been compared in order to study the influence of statistical noise and the number of sampled data. The application of this criterion permits us to obtain a radial distribution of the plasma parameters (densities and temperatures) from the spectral line profiles emitted by the discharge. The proposed criterion has been tested using the lateral intensities of several lines emitted by a microwave helium plasma column generated at atmospheric pressure.

Improving the analytical performances of inductively coupled plasma optical emission spectrometry by multivariate analysis techniques.

The various multivariate analysis techniques which have been successfully applied to maximize the analytical performance of ICP-OES are reviewed. These include optimization procedures, spectral data processing and calibration methods as well as classification and pattern recognition techniques.

Aluminium content of drinking waters, fruit juices and soft drinks: contribution to dietary intake.

Concentrations of aluminium in drinking waters (tap water, still mineral water and sparkling mineral water), fruit juices and soft drinks were determined using graphite furnace atomic absorption spectrometry (GFAAS) of samples processed with a HNO3-V205 acid digestion pre-treatment. In water samples, aluminium was determined directly. We verified the sensitivity, accuracy and precision of the method and ruled out matrix interferences. In analysed samples, aluminium values ranged from 4.2 to 165.3 microg/l in drinking water (n=41), from 49.3 to 1,144.6 microg/l in fruit juices (n=47), and from 44.6 to 1053.3 microg/l in soft drinks (n=88). According to the type of container (glass or can) statistically significant differences (P<0.01) have been demonstrated. Considering the mean daily individual consumption of these beverages in Spain, the daily dietary intake of Al supplied by this source is estimated as 156 microg/person/day. This study contributes new data on the Al content of a variety of foods and beverages in Spain and to estimate reliably the total dietary intake of aluminium.

The influence of saliva on the formation of calcium fluoride-like material on human dental enamel.

After a topical fluoride application two resulting features can be observed and measured: the formation of calcium fluoride and a decrease in caries incidence. For the formation of solid calcium fluoride the source of calcium may be either the enamel itself or remaining saliva or--in plaque--plaque fluid and calculus. The aim of the present study was to examine whether saliva through its calcium content has any influence on the amount of calcium fluoride formed by a topical fluoride treatment of enamel. The roots and the fissure systems of 64 freshly extracted intact third molars were covered with nail varnish and allocated to eight groups of 8. Half of the groups were put in fresh paraffin-stimulated saliva for 5 min after which surplus of saliva was shaken off whilst the other groups remained in distilled water. The teeth were given a 2-min topical treatment with either distilled water (control), neutral 0.2% NaF, neutral 2% NaF or 2% NaF acidified with 0.1 mol/l H3PO4. After the topical treatment the teeth were rinsed in running tap water for 5 min, dried and revarnished before determination of calcium fluoride. It was found that the amount of calcium fluoride formed depended on the concentration of fluoride (the higher the fluoride concentration, the higher was the amount of calcium fluoride), the acidity of the solution (presumably due to the increase in available calcium through enamel dissolution) and the presence of saliva (presumably due to its calcium content and its mucinous nature). As there was always more calcium fluoride formed in the presence of saliva, thorough drying of the teeth prior to topical treatments may be superfluous.

Determination of selenium in marine biological tissues by transverse heated electrothermal atomic absorption spectrometry with longitudinal Zeeman background correction and automated ultrasonic slurry sampling.

A fast, sensitive, and reliable method for determination of selenium in marine biological tissues by electrothermal atomic absorption spectrometry with slurry sampling was developed. Slurries were prepared from fresh and frozen seafood samples that were previously homogenized, dried, and ground; particle sizes <100 microm were taken for analysis. A 3% (v/v) HNO3 solution containing 0.01% (v/v) Triton X-100 was used as slurry diluent. Slurries were mixed on an automated ultrasonic slurry sampler at 20% amplitude for 30 s just before an aliquot was injected into the furnace. The method was successfully validated against the following certified reference materials: NRCC CRM DORM-2 (Dogfish muscle); NRCC CRM TORT-2 (Lobster hepatopancreas); NRCC CRM DOLT-2 (Dogfish liver); and BCR CRM 278 (Mussel tissue), and was subsequently applied to determination of Se in 10 marine biological samples. The influences of the drying procedure (oven-, microwave-, and freeze-drying), matrix modifier amount, mass of solid material in cup, and pipetting sequence are discussed. The limit of determination of Se was 0.16 microg/g and the repeatability, estimated as between-batch precision, was in the range of 4-8%. Se contents in the samples ranged from 0.6 to 2.8 microg/g. The proposed method should be useful for fast assessment of the daily dietary intake of Se.

The relation between lead concentrations in human dental tissues and in blood.

The purpose of this study was: (1) to measure the lead concentrations in various parts of the teeth (enamel, dentine and circumpulpal dentine) and in blood from individuals of a remote rural South African community; (2) to investigate any correlation between the lead concentrations in these various dental tissues and in blood; and (3) to estimate blood lead from the tooth lead concentrations reported in other studies. Primary teeth and blood were collected from 48 children and analysed by graphite-furnace atomic absorptiometry. The following median concentrations (expressed in mg/kg) of lead were found: blood, 0.025; enamel, 0.25; dentine, 2.04; circumpulpal dentine, 6.71. The tooth lead concentrations were similar to those from other studies from remote rural areas but comparisons of blood lead were not possible in the absence of previous data. Blood lead in other studies could be calculated from the ratios here reported.

Fluoride and magnesium concentrations in human dental calculus obtained from Japanese and Chinese patients.

Calculus deposited on a total of 68 permanent teeth from patients 30-60 years old from Nagoya in Japan and Beijing in China was investigated. An abrasive microsampling method was used to examine the fluoride (F) and magnesium (Mg) distribution, using a fluoride ion-specific electrode and atomic absorption spectrophotometry, respectively. F concentrations decreased from the surface towards the interior of the calculus. Mg concentrations, however, gradually rose towards the innermost surface adjacent to the tooth. In all parts of the depth profiles, the average concentrations of both magnesium and fluoride were higher in the Japanese than in the Chinese calculus. Towards the inner surface of the calculus, F and Mg concentrations were also much higher in the Japanese than in the Chinese group. A greater intake of sea foods and greater use of fluoride dentifrices are possible reasons for the higher F and Mg concentrations in the Japanese individuals.

[The zinc status in a selected Spanish population. A multivariate analysis]. / Status de zinc en una población española seleccionada. Análisis multivariante.

There are no previous studies on the zinc status in the healthy, adult, Spanish population. The objective of this study was to obtain the levels of zinc in the serum and hair of this population to determine the normal nutritional status of zinc, and evaluating the influence of certain factors like age, sex, type of residence, body mass index (BMI) hair color, or recent food intake (zinc and fiber contents of the diet) on this status. Using a simple randomized sampling, 186 blood donors of both sexes with ages comprised between 18 and 65 years, were selected. The results were analyzed using uni- and multi-variate statistical techniques. The average concentration of zinc in serum was 97.22 micrograms/dl (95% CI: 95.1-99.4); the average zinc level in hair was 163.86 micrograms/g (95% CI: 157.8-169.9). The serum zinc was individually associated with the type of residence and the zinc and fiber contents of the diet. The zinc in hair was associated with sex, age, body mass index, and hair color. Using a multivariate analysis, predictive models of multiple regression were obtained for the serum zinc: y = 109.69 - 1.39 (dietary zinc) - 4.63 (sex) - 0.65 (dietary fiber), for the zinc in the serum, and y = 199.34 + 26.62 (sex) - 2.08 (BMI) - 0.47 (age) for the zinc in the hair. The serum concentration decreases as the dietary zinc and fiber decreases and women have lower levels. The zinc in hair is increased in women and is reduced with increasing age and BMI.

Initial versus subsequent release of elements from dental casting alloys.

The release of elements from dental casting alloys is directly related to adverse biological effects they may have. Longer-term (>1 month) studies of elemental release have suggested that release decreases significantly after a higher initial release of elements. The aim of the current study was to measure the release of elements from a variety of clinically relevant dental casting alloys and compare the release at weekly intervals through 4 weeks. The hypothesis was that the release during the initial week should be higher than in subsequent weeks, and that cytotoxicity should decrease as elemental release decreases. Alloy samples were exposed to cell-culture medium which was changed at weekly intervals and assessed for elemental release by means of atomic absorption spectrometry. The cytotoxicity of the medium was also measured. The results showed that for single phase alloys, initial release was often significantly higher in the first weeks than in subsequent weeks, but not for all elements in an alloy. Multiple phase alloys showed steady or increasing release relative to the first week. Cytotoxicity relationships were complex depending on which elements were released and the ratios of elements released. This study suggests that short-term tests (<1 week) may not be appropriate to evaluate longer-term elemental release or cytotoxicity because of changing rates of elemental release.

[Multiple pregnancy and microelements: zinc (preliminary report)]. / Mnogoplodna bremennost i mikroelementi: tsink (predvaritelno suobshtenie).

The aim af the study was to define the concentration of zinc in sera of women with multiple pregnancies during the last trimester and to compare it with the values in normal pregnancies. The study included 12 women with gemini and 67 with single fetus pregnancies. A statistically significant decrease was found in the mean zinc concentration in twin pregnancies--8.1 +/- 1.72 mcmol/L compared to the mean values in normal pregnancies--10.5 +/- 1.90 mcmol/L (p < 0.001). Various mechanisms, possibly responsible for the stated changes, their relation to some complications of multiple pregnancy and delivery are discussed, as well as their prophylactics.

[The concentration of selenium in the maternal serum in cases of missed abortion]. / Kontsentratsiia na selen v maichiniia serum pri sluchai s missed abortion.

The changes in the serum level of selenium in cases with pathologic pregnancies are still not clear. The aim of the present study was to determine whether serum selenium in cases with missed abortion differed from selenium concentration in serum during first trimester of normal pregnancy. Twenty-three women with missed abortion and 61 with normal pregnancy were included in the study. We found a statistically significant (p < 0.001) elevation of serum selenium level in cases with missed abortion (928 +/- 335 nmol/l) comparing with those with normal pregnancy (568 +/- 77 nmol/l). We discuss the possible mechanisms of the observed changes.

[The zinc concentration of the blood serum in women with ovarian tumors (preliminary report)]. / Kontsentratsiia na tsinka v kruvniia serum pri zheni s tumori na iaichnitsite (predvaritelno suobshtenie).

The aim of the study is to determine the concentration of blood serum zinc of women with ovarian tumors. The patients included in the study are as follows: 15 women with benign ovarian cysts, 5 with endometrial cysts and 5 with ovarian carcinoma. The control group consists of 157 healthy women whose serum zinc concentration was 13.50 +/- 2.60 mmol/L. We could not demonstrate a significant difference in serum zinc concentration of different groups: benign cysts, endometrial cysts and ovarian carcinoma in comparison control group.