Inductively Coupled Plasma Atomic Emission Spectrophotometry Research Articles

Near-Infrared Spectroscopy Procedure for Online Determination of Sodium and Potassium Content in Low-Salt Cured Hams.

This paper reports the development of a near-infrared spectroscopy (NIRS) calibration procedure for the determination of sodium and potassium content in cured ham samples. Sliced samples of hams treated with different salts in different percentages were included in the study. Calibration models developed using partial least squares regression were cross-validated and predictive models were tested using the samples of cured ham with low sodium content. The results showed that the developed NIRS procedure is capable of directly measuring the potassium content of packaged dry-cured ham slices with low sodium content with a fitting accuracy of 91.44%, and that it can indirectly determine the sodium content by applying a correction factor to the values obtained for potassium. The prediction error between the calculated and actual sodium values determined using inductively coupled plasma atomic emission spectrophotometry (ICP-AES) was 0.004%, and this confirms that the NIRS procedure is a viable option for the determination of sodium and potassium content in this type of sample.

Diversity in Elemental Content in Selected Artemisia L. (Asteraceae) Species from Gilgit-Baltistan Region of Pakistan Based on Inductively Coupled Plasma Atomic Emission Spectrophotometry (ICP-AES).

Diversity in eleven Artemisia species from northern Pakistan was assessed based on as per suitability of their elemental contents with thermal conductivity detection and ICP-AES procedures. Results indicated the presence of 13 major elements in the Artemisia species with varied concentrations including Carbon (45.7%, 45,7000ppm-49.8%, 49,8000ppm), Nitrogen (2.03%, 20,300ppm-3.50%, 35,000ppm), Phosphorus (0.168%, 1680ppm-0.642%, 6420ppm), Potassium (2.38%, 23,800ppm-4.72%, 47,200ppm), Sulphur (1920ppm, 0.192%-4780ppm, 0.478%), Boron (23.8ppm, 0.00238%-71.7ppm, 0.00717%), Calcium (0.733%, 7330ppm-2.249%, 22,490ppm), Magnesium (0.116%, 1160ppm-0.267%, 2670ppm), Zinc (27.7ppm, 0.00277%-47.9ppm, 0.00479%), Manganese (25.7ppm, 0.00257%-93.8ppm, 0.00938%), Iron (353ppm, 0.0353%-1532ppm, 0.1532%), Copper (14.1ppm, 0.00141%-26.2ppm, 0.00262%) and Sodium (105ppm, 0.0105%-587ppm, 0.0587%). Cluster analysis distributed the Artemisia species into two major groups (G1 and G2) on the basis of their elemental content where G1 contained species like, Artemisia herba alba Asso., A. tournefortiana Rachb., A. rutifolia Steph. ex Spreng., and A. vulgaris L., with the presence of all elements with the maximum amount of S, Zn, P, Ca, and Mg, while G2 contained species like Artemisia biennis Willd., A. chamaemelifolia Vill., A. capillaris, L., A. gmelinii Weber ex Stech., A. indica Willd., A. maritima L., and A. verlotiorum Lamotte., with all elements but significant concentrations of B, N, C, K, Mn, Fe, Cu, and Na. PCA analysis displayed maximum species diversity in the axes two, while axes one showed lower diversity. Additionally, the elevated levels of elements recorded as compared to the threshold levels recommended in the literature for medicinal plants require extraordinary precautionary measures before or during using Artemisia as medication to avoid metal toxicity.

Influence of Water Treatment and Wastewater Treatment on the Changes in Residues of Important Elements in Drinking Water.

Drinking water is the essential medium for food production, and is also needed for direct consumption; while it must be free of harmful substances, it also must have a composition that is beneficial to health. The aim of this study was to evaluate the influence of water and wastewater treatment on reducing the concentrations of zinc (Zn), nickel (Ni), iron (Fe), manganese (Mn), copper (Cu), lead (Pb), and arsenic (As) in the Western Pomerania Voivodeship in Poland. The research was carried out in 2017–2019. The analysis was performed with inductively coupled plasma atomic emission spectrophotometry (ICP-AES). The concentrations of trace elements in drinking water were below maximum acceptable concentrations (MACs). Reductions in the most dangerous elements during water treatment fluctuated from 48.5% (As) to 97% (Pb). Wastewater treatment reduced the concentrations of analyzed elements by a range of 28.6 to 60.8%, and the most toxic elements (Pb and As) by over 50%. Trace element concentrations in treated wastewater were below MAC values, and ranged from 1.15% (Pb) to 6.23% (As) of MACs for toxic elements. The concentrations of both essential elements (Zn, Ni, Fe, Mn, Cu) and toxic elements (Pb, As) in drinking water were below the MACs. Water treatment had a significant (p < 0.05) effect on decreasing trace element concentrations.

Heavy metals and trace elements in scalp hair samples of children with severe autism spectrum disorder: A case-control study on Jordanian children

BackgroundElemental analysis has been increasingly used for biomonitoring heavy metals and trace elements. MethodsThis study monitored the levels of two heavy metals (Al and Pb), and seven trace elements (Macroelements Mg, K, P and Ca; Microelements Zn, Cu, Fe) in scalp hair of 57 children with severe autism spectrum disorder (ASD) and 50 age-matched controls, using Inductively Coupled Plasma Atomic Emission Spectrophotometry (ICP-AES). ResultsCompared to controls, significantly higher levels of Al (p = 0.001), Pb (p = 0.001) and K (p = 0.021), with lower levels of Mg and Zn (p = 0.038) were observed for the ASD group. ASD boys had higher levels of Al (p = 0.001), Pb (p = 0.001) and K (p = 0.017) than control boys, while ASD girls had higher Pb levels (p = 0.005) than control girls. The ASD subgroup exposed to passive smokers had higher levels of Al (p = 0.033) and Pb (p = 0.001, and the ASD subgroup not exposed to passive smoke had higher levels of Al (p = 0.011), Pb (p = 0.001), K (p = 0.003); and lower levels of Mg (p = 0.011) than their controls. Other confounding factors and the correlation between these elements were also investigated. ConclusionThis data suggests that exposure to Al and Pb, increase intake of K, and decreased intake of magnesium and zinc, may contribute to ASD etiology.

Estimation of Zinc Levels in Blood, Liver and Stomach Contents using ICP-AES: A Cross Sectional Autopsy Based Study

Zinc is an essential component of the body, but its excess quantity is harmful and long term intake above upper limits causes acute or chronic toxicity. Normal levels of zinc in serum is 75-120 µg/dL while in blood it is 1200 µg/dL. A study was conducted to determine the level of zinc in various biological samples from the medicolegal autopsies conducted at mortuary, Department of Forensic Medicine &amp; Toxicology, All India Institute of Medical Sciences, New Delhi. Biological samples were taken from 100 cases comprising of Blood, Liver &amp; Stomach contents from each case. They were analysed using Inductively Coupled Plasma-Atomic Emission Spectrophotometry (ICP-AES). The data obtained were analysed using various demographic profiles and treatment history to know prevalence &amp; distribution of these metals in general population so as to help later in investigation of alleged deaths due to metal toxicity &amp; metallic compounds poisoning. The result showed mean blood zinc levels were 14.21 μg/ ml (range 0-77.36 μg/ml), mean zinc levels in liver and stomach contents were 25.66 μg/g (range 0.72–127.03 μg/g) and 7.95 μg/ml (range 0–60.94 μg/ml) respectively. The data analysis on the basis of treatment history showed that mean zinc levels in blood, liver and stomach contents were higher in cases where treatment was not given i.e. 14.97 µg/ml, 15.25 µg/g and 8.18 µg/ml respectively.

Chemical fractionation and mobility of metals in floodplain soils of the lower reaches of the River Niger, Nigeria

The chemical fractionation of nine metals, Cd, Pb, Cr, Ni, Cu, Co, Ba, Mn and Zn, in soil profiles of the floodplain of the lower reaches of the River Niger in Nigeria, was investigated with a view to providing information on the forms, bioavailability and mobility of these metals in the soil profiles. The chemical forms of metals in the soil were determined by using the European Community Bureau of Reference (BCR) sequential chemical extraction method and the concentrations were measured by inductively coupled plasma-atomic emission spectrophotometry (ICP-AES). The results indicated that the residual and Fe-Mn oxide/hydroxide phases were the predominant forms of the metals in the soil profiles. The percentage of metals in the readily available and potentially available fractions followed the order: Pb > Ba > Cd > Ni > Co > Zn > Mn > Cu > Cr. Significant proportions of these metals were found in the potentially available phases, which indicate an increase in mobility and availability as a result of changes in the physicochemical characteristics (pH and Eh) of the soil following flooding events.

Spatio-temporal distribution of metals in household dust from rural, semi-urban and urban environments in the Niger Delta, Nigeria.

Concentrations of metals in household dust samples from rural, semi-urban and urban zones of the Niger Delta in Nigeria were measured during both 2009 and 2014 with the aim of providing information on changes in the concentrations, distribution patterns, sources and risks of metals in these zones. The concentrations of metals in the dust samples were quantified by using inductively coupled plasma atomic emission spectrophotometry (ICP-AES) after digestion with aqua regia. The measured concentrations (mgkg-1) of metals in the three zones within the study periods were as follows: <LOQ-21.2; <LOQ-182; 7.90-265; <LOQ-117; <LOQ-471; 3.37-2310; 0.35-7.9; 4.25-365; 6.78-61,600; 219-37,700; and 1180-18,000 for Cd, Pb, Ba, Cr, Ni, Cu, Co, Mn, Zn, Fe and Al, respectively. The results from the two periods indicate significant changes in the concentrations, distribution patterns and risk factors which reflects a deterioration of the quality of the household environment over this time span. The hazard index (HI) values calculated for children were greater than 1 indicating significant non-cancer risks for these subjects in these areas. The HI values for adults were less than 1 and consequently do not pose a significant risk. The carcinogenic risk levels for exposure to metals for both adults and children in these zones were below the range specified as safe by the US EPA (×10-6 and ×10-4) thereby indicating a low cancer risk. The sources of metals in household dust from these zones include emissions from industries, traffic, artisanal workshops and releases from household furniture, metal-based fittings, metal roofing and pesticides.

Surfactant-assisted synthesis of ceria-titania-rich mesoporous silica materials and their catalytic activity towards photodegradation of organic dyes.

Ceria-titania doped highly ordered hexagonal and cubic mesoporous silica composite samples with varying amounts of Ce and Ti have been synthesized using hexadecyltrimethylammonium bromide (CTAB) surfactant as a template under basic conditions in the presence of ammonia. The removal of the template resulted in the formation of mesoporous composites doped with Ce and Ti, which were thoroughly characterized via small-angle X-ray scattering (SAXS), wide-angle X-ray diffraction (WAXRD), N2 adsorption, scanning and transmission electron microscopy analysis with energy-dispersive spectrometry mapping (SEM-TEM-EDS), inductively coupled plasma atomic emission spectrophotometry (ICP-AES), and ultraviolet-visible diffuse reflectance spectrometry (UV-visible). The electronic states of Ti and Ce species present on the surface of silica were also investigated by X-ray photoelectron spectroscopy (XPS). The catalytic activity of these Ti-modified ceria-silica samples for the photodecomposition of rhodamine B under visible-light irradiation was investigated. The results revealed that a sample with a higher Ti content, as well as equal amounts of Ce and Ti, displayed higher catalytic activity for the photodegradation of the organic dye rhodamine B.

On-line prediction of sodium content in vacuum packed dry-cured ham slices by non-invasive near infrared spectroscopy

In the present study, non-invasive near infrared spectroscopy (NIRS) was evaluated as a potential on-line analytical technique to predict the sodium content in dry-cured ham slices. Samples of 310 packages were scanned by applying a remote fibre-optic probe to the surface of the slices, at different temperatures, with no previous manipulation. The sodium content of the meat samples was determined by a reference method based on Inductively Coupled Plasma Atomic Emission Spectrophotometry (ICP-AES) after chemical digestion. Partial least squares (PLS) regression was used as a chemometrics method to perform the calibrations. The models yielded acceptable results with cross validation correlation coefficients (R2CV) determined 86.2–90.2%. The prediction capacity reached in the external validation was 3.63, with a standard prediction error of 0.12% Na. These results show that NIR measurements could be implemented on the packaging line of dry-cured ham slices to provide accurate and relevant information about the sodium content of each packaged products.

Trace Element Concentrations in Human Tissues of Death Cases Associated With Secondary Infection and MOF After Severe Trauma.

Proper trace element level is crucial for the organs in maintaining normal physiological functions. Multiple organ failure (MOF) might be added to critically ill patients due to a lack of trace elements. Alterations of trace element levels in brain, heart, liver, and kidney after severe trauma, however, have been little studied so far. In this study, tissue samples of the frontal cortex of the brain, interventricular septum of the heart, right lobe of the liver, and upper pole of the kidney were obtained from forensic autopsies, of which 120 cases died during the 5th to 15th day of hospitalization, whereas the trauma death group and 43 cases immediately died due to severe craniocerebral trauma as the control group. Copper (Cu), iron (Fe), zinc (Zn), and selenium (Se) were quantified by inductively coupled plasma atomic emission spectrophotometry (ICP-AES). Cu, Fe, Zn, and Se concentrations in the brain, heart, liver, and kidney in the trauma group decreased dramatically (p<0.05) compared to the control group. The incidence of secondary infection and multiple organ failure (MOF) in the trauma death group were 78.33 and 29.17%, respectively. The concentrations of all elements exhibited a significant correlation with secondary infection and MOF (p<0.01). Our data suggest that low concentrations of Cu, Fe, Zn, and Se in pivotal organs may contribute to the incidence of secondary infection and MOF after severe trauma, which to some extent results in death.

One-million year Rare Earth Element stratigraphies along an Antarctic marine sediment core

An integrated system, based on Inductively Coupled Plasma-Sector Field Mass Spectrometry (ICP-SFMS) and Inductively Coupled Plasma-Atomic Emission Spectrophotometry (ICP-AES) techniques, was optimised for the geochemical characterisation of soils and marine sediments. Sample mineralization was carried out with HF, HNO3 and HClO4. Operative blanks were at least two orders of magnitude lower than the lowest concentration measured in real samples. For ICP-SFMS, the detection power of the method in high resolution mode was sufficient for an accurate quantification of metals, yet avoiding REEs' (Rare Earth Elements) isobaric interferences. Once tested the accuracy on six certified materials, the methods were applied to the analysis of 39 major and trace metals on the top 90m of sediments from the ANDRILL AND-1B core, covering the last million years.Stratigraphies of REEs and of normalised markers from this core clearly highlight a discontinuity at about 660,000years before present. This pattern is well shown by the results of a PMF (Positive Matrix Factorization) statistical analysis, revealing two different sources for the sedimentary material, whose relative contribution changed around that time. Such a result is consistent with previous studies and confirms the net change in the provenance of glacial fluxes in the McMurdo region (Ross Ice Shelf, Antarctica) in the last million years.

Leaching of elements from packaging material into canned foods marketed in India

The interaction between food and metal packaging can be a potential source of trace elements release, which if ingested by humans can cause harmful effects. The present study is undertaken to investigate the leaching of elements from packaging materials into canned foods under different conditions of temperature, pH and storage period. Elemental analysis was done using Energy Dispersive-X-Ray Fluorescence (ED-XRF) for packaging materials and Inductively Coupled Plasma-Atomic Emission Spectrophotometry (ICP-AES) for canned foods. The concentration of Aluminum, Iron, Manganese, Silicon and Tin in the canned food products selected for analysis were found to be in range of 4.40–21.59 mg/kg, 2.38–19.70 mg/kg, 0.19–5.97 mg/kg, 16.46–359.63 mg/kg and 1.99–138.48 mg/kg respectively, when stored at room temperature within their shelf life storage period. The data revealed that the concentrations of elements under study were above the recommended limits of FAO/WHO Codex Alimentarius Commission.

Magnetic iron oxide nanoparticles embedded in SBA-15 silica wall as a green and recoverable catalyst for the oxidation of alcohols and sulfides

Iron oxide nanoparticles were synthesized in situ for the preparation of ordered mesoporous silica SBA-15 through the hydrothermal method to afford Fe2O3/SBA-15 catalyst. The synthesized catalyst was characterized by X-ray diffraction (XRD), nitrogen adsorption–desorption measurement, transmission electron microscopy (TEM), vibrating sample magnetometer (VSM) and inductively coupled plasma atomic emission spectrophotometry (ICP-AES). The catalytic activity was tested for the oxidation of alcohols and sulfides. Easy recovery, good reusability, high conversion and relatively short reaction times were observed for the mentioned catalyst.

Seasonal variations of metal concentrations in muscle tissue of tench (Tinca tinca), water and sediment in Beysehir Lake (Turkey)

Concentrations of 10 metals (Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) in muscle tissue of tench (Tinca tinca), water and sediment in Beysehir Lake were analysed using inductively coupled plasma atomic emission spectrophotometry (ICP‐AES). Tench is one of the most abundant fish species in Beysehir Lake. Metal levels were analysed in only the muscle tissue of the fish, because this provides information on the potential risk to the fish themselves and to consumers of these edible portions of the fish. The Cu concentration was the highest in all the samples of the lake's sediments and waters, studied in all seasons, and ranged between 24.01 µg g−1 (in spring) and 90.30 µg g−1 (in summer), but Cu concentrations in T. tinca were low: 0.03 µg g−1(in summer) to 0.21 µg g−1(in spring). Metal concentrations in sediments, waters and tench varied seasonally. All metal concentrations in sediments were higher than those in water and fish. However, all metal concentrations, except Zn, were lowest in fish muscle tissue.

Detection of environmentally persistent free radicals at a superfund wood treating site.

Environmentally persistent free radicals (EPFRs) have previously been observed in association with combustion-generated particles and airborne PM(2.5) (particulate matter, d < 2.5um). The purpose of this study was to determine if similar radicals were present in soils and sediments at Superfund sites. The site was a former wood treating facility containing pentachlorophenol (PCP) as a major contaminant. Both contaminated and noncontaminated (just outside the contaminated area) soil samples were collected. The samples were subjected to the conventional humic substances (HS) extraction procedure. Electron paramagnetic resonance (EPR) spectroscopy was used to measure the EPFR concentrations and determine their structure for each sample fraction. Analyses revealed a ∼30× higher EPFR concentration in the PCP contaminated soils (20.2 × 10(17) spins/g) than in the noncontaminated soil (0.7 × 10(17) spins/g). Almost 90% of the EPFR signal originated from the minerals/clays/humins fraction. GC-MS analyses revealed ∼6500 ppm of PCP in the contaminated soil samples and none detected in the background samples. Inductively coupled plasma-atomic emission spectrophotometry (ICP-AES) analyses revealed ∼7× higher concentrations of redox-active transition metals, in the contaminated soils than the noncontaminated soil. Vapor phase and liquid phase dosing of the clays/minerals/humins fraction of the soil with PCP resulted in an EPR signal identical to that observed in the contaminated soil, strongly suggesting the observed EPFR is pentachlorophenoxyl radical. Chemisorption and electron transfer from PCP to transition metals and other electron sinks in the soil are proposed to be responsible for EPFR formation.

ChemInform Abstract: Novel Method for Synthesis of γ-Lithium Vanadium Oxide as Cathode Materials in Lithium Ion Batteries.

γ-LixV2O5 (x = 0.9−1) was synthesized at 350 °C. The material was characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The synthesis reactions were studied by thermogravimetric analysis (TGA). The composition of γ-LixV2O5 was determined by atomic absorption spectrophotometry (AAS) and inductively coupled plasma−atomic emission spectrophotometry (ICP-AES). Its electrochemical performance as cathode active materials was studied by galvanostatic charge−discharge and cycle voltammetry. γ-LixV2O5 could deintercalate lithium ion reversibly. The potential vs Li+/Li electrode was from 2.6 to 4.0 V. γ-LixV2O5 has potential as starting electrode active material in lithium ion batteries.

Variations of brain magnetic resonance imaging among manganese-exposed workers

Variations of the signal intensities in the magnetic resonance (MR) T(1)-weighted image (T(1)WI) of globus pallidus among manganese(Mn)-exposed workers were explored to provide a scientific basis for exposed biomarker of manganese-injured central nervous system (CNS). The brain MR T(1) and T(2) WI in eighteen male asymptomatic Mn-exposed, eight manganism and nine healthy control workers were examined routinely by adopting a 1.5 Tesla signal superconducting system. The SIGP and the signal intensity in frontal white matter (SIFWM) in the same side were determined, then pallidal index (PI) was calculated. Concentration of MnO(2) in workplaces and content of manganese in red blood cell (MnRBC) among workers were respectively determined by flame atomic absorption spectrometer (AAS) and inductively coupled plasma-atomic emission spectrophotometry (ICP-AES). The follow-up investigation in the eight high Mn-exposed workers was made one year later. The results showed that the median of air MnO(2) in smelting workplace was 0.64 mg/m(3)(0.07 - 5.40 mg/m(3)), which were respective 0.56 mg/m(3)(0.09 - 1.71 mg/m(3)) in power distribution room (low Mn-exposure) and 0.89 mg/m(3) (0.07 - 5.40 mg/m(3)) in furnace (high Mn-exposure). PI in the Mn-exposed and high Mn-exposed workers were both higher than those of the manganism and control workers(116.4 +/- 8.2, 119.0 +/- 7.9, 105.3 +/- 8.4 and 102.2 +/- 1.5, respectively. Mn vs control, t' = 7.146, P = 0.000; Mn vs manganism, t = 3.181, P = 0.004. High Mn-exposure vs control, t' = 7.446, P = 0.000; high Mn-exposure vs manganism, t = 3.763, P = 0.001). The increased signal in T(1)WI of globus pallidus was observed in Mn-exposed workers, especially in high Mn-exposed workers. The content of manganese in red blood cell of Mn-exposed and control workers was significantly higher than those of the manganism workers [(151.6 +/- 40.5) ng/ml, (149.2 +/- 21.3) ng/ml, (154.5 +/- 46.6) ng/ml, (144.4 +/- 14.2) ng/ml, (20.8 +/- 7.4) ng/ml respectively. The difference was significant in statistics. Manganism vs control, t = 20.206, P = 0.000; manganism vs Mn, t' = 13.144, P = 0.000; manganism vs low and high Mn, t' = 12.964, 9.957, respectively, P = 0.000]. Only a decreased median of air MnO(2) in furnace was found one year later (0.89, 0.31 mg/m(3), Z = -2.142, P = 0.032). The difference was significant in statistics. Our data suggests that SIGP of MR T(1)WI among workers was obviously increased by manganese-exposure. PI may be taken as the signal of CNS injury which was induced by manganese-exposure.

Mg/Ca ratios in the planktonic foraminifer Neogloboquadrina pachyderma (sinistral) from plankton tows in the Ross Sea and the Pacific sector of the Southern Ocean (Antarctica): comparison of different methodological approaches

Mg/Ca ratios in living specimens of the planktonic foraminifer Neogloboquadrina pachyderma (sin.) have been investigated using Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) and ultracleaning procedures on ‘bulk’ foraminifera followed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Inductively Coupled Plasma Atomic Emission Spectrophotometry (ICP-AES) analysis. Plankton tows were taken in the upper 250 m of the water column at different sites in the Ross Sea and at the Polar Front of the Pacific Ocean during 6 austral summers. We found high values of Mg/Ca ratios in N. pachyderma (s.) not previously reported in the literature. Our data suggest that at least two factors influence the results: (1) the presence of some protoplasm in the test of living specimens, which seems to control the actual Mg concentration and (2) the morphotype of the analysed specimens in term of test thickness.

The Detection of Salivary Minerals in Smokers and Non‐Smokers With Chronic Periodontitis by the Inductively Coupled Plasma‐Atomic Emission Spectrophotometry Technique

The purpose of this study was to evaluate the effect of smoking on the salivary minerals in subjects with chronic periodontitis by the inductively coupled plasma-atomic emission spectrophotometry (ICP-AES) technique. The study group included 24 subjects-12 smokers and 12 non-smokers-with chronic periodontitis. Clinical measurements and non-stimulated whole saliva were obtained, and the levels of five elements-sodium, potassium, calcium, magnesium, and phosphate-in each specimen were analyzed. When the clinical parameters were compared between groups, only plaque index was significantly higher in smokers than non-smokers (P <0.05). The mean plaque index of smokers and non-smokers was 1.93 +/- 0.51 and 1.51 +/- 0.39, respectively. The results of this study showed that there were no significant differences between groups in the mineral content of saliva. In smokers, there were positive correlations between the levels of calcium, sodium, and magnesium and clinical attachment level. There was also a positive correlation between the level of phosphate and the percentage of bleeding on probing. In non-smokers, there was a negative correlation only between the mean level of sodium and plaque index (P <0.05). The present study showed that no significant differences were found between the mineral content of saliva of smokers and non-smokers by the ICP-AES technique. It is a useful, fast, and sensitive technique compared to other techniques, and it can be advised for researchers while analyzing the mineral content of saliva.

EFFICIENCY OF MULTINUTRIENT EXTRACTANTS FOR THE DETERMINING OF AVAILABLE ZINC IN SOILS

The increasing use of the ICP-AES (inductively coupled plasma atomic emission spectrophotometry) as a multielement analytical technique has stressed the preference for the use of multinutrient extractants in routine soil analysis. However, few studies relating the extraction of zinc (Zn) from soil with such extractants and the absorption of the element by plants have been published. Two experiments under greenhouse conditions were carried out in order to determine the efficiency of some multinutrient extractants for the determination of available Zn in 44 soils from the State of São Paulo, Brazil, for corn and soybean. All soil samples were limed to increase the CEC's base saturation at pH 7 to 70%. Twenty-two soil samples with DTPA (diethylenetriaminepentaacetic acid) extractable Zn concentration lower than 0.6 mg dm−3 received either the application of B, Cu, Mn, Zn or of these micronutrients excluding Zn. The remaining 22 soil samples, with Zn concentration above 0.6 mg dm−3, received application of three micronutrients (B, Cu and Mn). Macronutrients were applied to all pots as needed for crop development. Zinc was extracted from the soils before each planting using the extracting solutions, DTPA, Mehlich 1 (M-1), Mehlich 3 (M-3) and AB-DTPA (ammonium bicarbonate-DTPA) and determined by ICP-AES. The results showed significant correlations between plant Zn concentration and soil Zn concentration. The correlation values between soil-Zn and plant-Zn were of 0.74 (M-3), 0.73 (DTPA), 0.62 (AB-DTPA) and 0.61 (M-1) for corn, and of 0.71 (DTPA), 0.63 (M-1), 0.58 (M-3) and 0.46 (AB-DTPA) for soybean. Thus, the DTPA solution was the most efficient extractant for the determination of bioavailable Zn when both crops are considered together.