Inductively Coupled Argon Plasma Emission Spectroscopy Research Articles

Evaluation of metallothionein formation as a proxy for zinc absorption in an in vitro digestion/Caco-2 cell culture model

Caco-2 cell metallothionein (MT) formation was studied to determine if MT could be used as a proxy for zinc (Zn) absorption in a cell culture model. The MT intracellular concentration was determined using a cadmium/hemoglobin affinity assay. The cellular Zn uptake was determined by acid digests (5% HNO(3)) using inductively-coupled argon-plasma emission spectroscopy. The effect of phytic acid (PA) on cellular Zn and MT concentrations was also studied. Cells were treated with a media containing 0, 2, 5, 10, 25, 50, 75 μmol L(-1) Zn (ZnCl(2)). The effect of varying the Zn:PA molar ratios (1:0, 1:1, 1:5, 1:10, 1:20) on the Zn uptake and MT formation was determined. The results showed a positive linear correlation between Zn-media concentrations and cellular Zn uptake, and MT formation was observed. Zn and MT concentrations in the cells treated with increasing levels of Zn (>25 μmol L(-1) Zn) were elevated. The Zn and MT concentrations in the cells incubated with Zn (when <10 μmol L(-1)) were similar to the untreated cells. PA significantly lowered the cellular Zn and MT concentrations. When the Zn:PA molar ratios were >1:5, cellular MT concentrations were no different to untreated cells. When a combined in vitro digestion/cell model was used, the cellular MT concentrations in white or red beans and fish samples were no different to the cell baseline. This study suggests that measurements of cellular Zn and MT concentrations have some limitations (<10 μmol L(-1) Zn). PA was observed to be a potent inhibitor of Zn uptake. Under the conditions of this in vitro model, Caco-2 cell monolayers are not useful for evaluating the Zn availability from foods.

Evaluation of Metallothionein formation as a proxy for zinc absorption in an in vitro digestion/Caco‐2 Cell culture Model

Caco-2 cell metallothionein (MT) formation was studied to determine if MT could be used as a proxy for zinc (Zn) bioavailability in an in vitro/cell culture model. The intracellular concentration of MT was determined using a cadmium/hemoglobin affinity assay. Total cellular Zn uptake was determined on acid treatment (5% HNO3) using inductively-coupled argon-plasma emission spectroscopy (ICPES). The effect of phytic acid (PA) on cellular MT formation was also studied. Caco-2 cells were treated with media containing 0, 2, 5, 10, 25, 50, and 75 μmol/L Zn (as ZnCl2). Some Zn absorption studies employed radio-Zn (65ZnCl2). The effect of varying Zn:PA molar ratios (i.e., 1:0, 1:1, 1:5, 1:10, and 1:20) on Zn uptake was determined. A positive correlation between Zn-media concentrations and cellular 65Zn uptake and cellular MT formation was observed. The concentrations of Zn and MT in cells treated with increasing levels of non-radioactive Zn (i.e., 25, 50 or 75 μmol/L Zn) increased as Zn concentrations in the media increased. Zn and MT concentrations in cells incubated with non-radioactive Zn (2, 5 or 10 μmol/L) did not differ from that of cells receiving no added Zn. The presence of PA significantly lowered the cellular MT concentration. When Zn:PA molar ratios were at or above 1:5, cellular MT concentrations were not different from that of cells receiving no added PA. The results of the study suggest that the measurements of cellular Zn and MT concentration have some limitations at or below 10 μmol/L Zn. The initial Zn status of cells may play a role in cellular MT synthesis. Further studies are required to validate the usefulness of using MT as a proxy for Zn absorption in Caco-2 cells. Funded by HarvestPlus.

Effects of Sewage-Sludge Application on Soils and Sunflower Yield: Quality and Toxic Element Accumulation

ABSTRACT Sunflower nutrition, sewage-sludge nutrients, and trace-metals supply have been studied in detail, but separately. The objective of the present work was to study the effects of sewage sludge on sunflower yields and the accumulation of nutrients and trace metals in soils and in the crop. Three experiments with sunflower were therefore conducted on farms located in Buenos Aires Province, Argentina. The treatments were control, 7 t dry matter (DM) sewage sludge/ha, and 14 t DM sewage sludge/ha. Soils were Typic Argiudolls and a Typic Hapludoll. At physiological maturity, grains and aerial biomass were harvested. Nitrogen (N), phosphorus (P), and potassium (K) were determined and, after digestion with acids, cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), nickel (Ni), and zinc (Zn) were analyzed with inductively coupled argon plasma emission spectrometry (ICPES). Soil samples were taken and analyzed for nutrients and Cd, Cr, Cu, Ni, Pb, and Zn. Only available P and nitrate-N increased in the soil after the application of sewage sludge. Sunflower yields increased by increasing grains per head. Individual grain weight, oil content, nutrients, and trace-metals concentrations were not affected, nor were the aerial biomass and its composition. Using sewage sludge according to standard regulations does not affect either toxic-metals uptake or sunflower quality.

Baseline Levels of Potentially Toxic Elements in Pampas Soils

The soils of the Pampas are thought to be generally non-contaminated but there is growing evidence of trace element accumulation at some specific sites. The goal of this study was to measure the current levels of the main Potentially Toxic Elements (PTE) in the top horizon and in specific soil profiles so that we would establish the baseline concentrations of these elements. Eighty-eight top soils and three soil profiles were sampled. The samples were acid digested. Arsenic, boron, barium, cadmium, cobalt, chromium, copper, lead, manganese, mercury, molybdenum, nickel, silver, selenium and zinc were determined with inductively coupled argon plasma emission spectrometry (ICPES). All of the values found are within the normal range for uncontaminated soils as reported from several continents. Elements with high environmental risk potential are lower than the admissible range of the European Union and some of them are orders of magnitude lower than those of the United States Environmental Protection Agency (US-EPA) 501 levels. Potentially Toxic Elements contents increased with depth or showed a maximum concentration at the B2 horizon. This is related to the parent material and the pedogenetic processes but not to recent contamination. Soil profiles showed higher concentrations of PTE in clayey horizons. However, these relationships did not appear in top soil samples in any soil Great Group studied. The shown data establishes a baseline for PTE concentrations for Pampas soils.

Comparison of mineral and cholesterol composition of different commercial goat milk products manufactured in USA

Concentrations of 12 major and trace minerals and cholesterol in commercial goat fluid milk, evaporated, powdered, yogurt, and cheese products manufactured in the US were evaluated for compositional differences. Minerals were determined by an Inductively Coupled Argon Plasma Emission Spectroscopy (ICAP), while cholesterol was analyzed using colorimetric and gas chromatographic (GC) methods. Mean total solids content (%) of fluid milk, evaporated milk, powdered milk, yogurt, plain soft and Monterey Jack cheeses were: 11.3, 20.9, 94.1, 11.5, 32.5, and 57.7, respectively. Mean calcium and phosphorus contents (ppm, dry basis) of the corresponding products were: 103, 125; 440, 393; 7715, 7471; 161, 144; 691, 1105; 3492, 3067, respectively. The respective iron and zinc contents (ppm) of the corresponding products were: 0.062, 0.349; 1.518, 1.635; 3.33, 30.21, 0.117, 0.338; 7.16, 3.64; 8.86, 3.81. The levels of potassium (K) in cheeses were lowest among all the products including fluid goat milk, suggesting that a significant amount of K was lost during cheese manufacturing processes. Levels of all trace minerals were higher in yogurt and cheeses than in fluid milk. The levels of trace minerals in cheeses were greater than those in yogurt products. Iron and aluminum contents of certain goat milk products were considerably higher than normal, possibly due to contamination of minerals from manufacturing utensils and product metal cans. Sulphur contents of fermented products were significantly greater than those of fluid milk, which may be accountable for the microbial synthesis of sulfur containing proteins during the manufacturing processes of the products. Cholesterol contents (mg/100 g, wet basis) of fluid, evaporated, powdered goat milk and Monterey Jack cheese determined by GC method were: 11.0, 24.9, 119.5 and 91.7, respectively. Cholesterol contents of the goat milk products analyzed by colorimetric method were substantially greater than those by GC method.

Extraction of boron from soil by microwave heating for ICP‐AES determination

Abstract Extraction with hot water is the most widely used procedure to determine boron (B) in soils for the diagnosis of the nutrient availability for plants. However, this procedure is tedious for routine conditions and requires some special precautions. An alternative extraction procedure was developed, consisting in the extraction of B with a 1.25 g/L solution of barium chloride (BaCl2) or with water heated in a domestic microwave oven. Boron was determined either by inductively coupled argon plasma emission spectrometry (ICP‐AES) and by spectrophotometry with azomethine‐H. Good correlations were found between the extraction by boiling water under reflux and the extraction by the microwave heating for 13 Brazilian soils, and the contents of B obtained by spectrophotometry did not differ significantly from those obtained by ICP‐AES. Considering the calculated standard deviations, it can be concluded that microwave heating followed by ICP‐AES determination is an adequate procedure for the determination ...

Uptake of metals from chromated-copper-arsenate (CCA)-treated lumber by epibiota

Previous studies have shown that Cu, Cr, and As leach from chromated-copper-arsenate (CCA) pressure-treated wood and can be toxic to estuarine organisms in the laboratory. In this study, algae, barnacles, and mussles were collected from CCA-treated wood in open water and in a residential canal adjoining Santa Rosa Sound, Pensacola Beach, Fl, and were analysed for the metals by inductively-coupled argon plasma emission spectroscopy. Reference organisms were collected from nearby rocks. Organisms living on the open water dock had significantly (P<0.05) elevated concentrations of contaminants from the wood, while those living inside the canal had considerably higher concentrations. The highest concentrations in barnacles were found in those barnacles growing on new (1 year old) wood within the canal, reflecting the greater leaching of new wood.

Evaluation of soil sulfate extractants and methods of analysis for plant available sulfur

Abstract A steady decline in sulfur additions to Atlantic Canadian soils has prompted the need for an accurate method of determining their plant available sulfur status. Three soils were extracted with five soil extractants ‐ 0.01M Ca(H2PO4)2‐H2O in 2M HOAc, 0.1M CaCl2, Bray‐1 and de‐ionized water. The soil extracts were analyzed for sulfur or sulfate using inductively coupled argon plasma emission spectrometry (ICAP), AutoAnalyzer (AAN), anion exchange‐high performance liquid chromatography (HPLC‐CD) or atomic absorption spectroscopy (AAS). Results were compared with plant response of sulfur treatments to red clover, ryegrass, canola and wheat in a growth room. Instrument reproducibility and crop response indicated the ideal method of determining plant available soil sulfur was HPLC‐CD using the extractant Ca(H2PO4)2‐H2O.

Tissue disposition of boron in male Fischer rats

Boric acid (H 3BO 3), an inorganic acid with widespread commercial use and consumer exposure, impairs fertility in male rodents at dose levels lower than those required to cause other adverse effects. Previous studies found a testicular lesion in adult Fischer rats fed 9000 ppm boric acid (1575 ppm boron) and slightly reduced basal serum testosterone levels. A CNS-mediated hormonal component to this lesion was suggested. Detailed data on the tissue disposition of boron in the rat, including accessory sex organs and the brain, are lacking. This study examined the tissue disposition of boron in reproductive, accessory sex organs, and other selected tissue in adult male Fischer rats fed 9000 ppm boric acid to determine if selective accumulation of boron in reproductive tissues, accessory sex organs, and/or the brain might correlate with and explain the apparent selective testicular toxicity. Adult male Fischer rats were fed 9000 ppm boric acid for up to 7 days. Animals were killed at 1,2,3,4, and 7 days after the start of exposure. Plasma and excised tissues were heat-digested in acid and analyzed for boron by inductively coupled argon plasma emission spectrometry (ICAP). With the exception of adrenal glands, control boron levels in all tissues examined were below 4 μg/g. There was a rapid increase in plasma and tissue boron 1 day after the start of exposure (range 2- to 20-fold), with the exception of adipose tissue. With the exception of bone and adipose tissue, all soft tissues examined, including the testis, epididymis, accessory sex organs, hypothalamus, and rest of brain, appeared to reach steady-state boron levels (range 12–30 μg/g) by 3–4 days. Bone boron levels continued to increase up to the termination at 7 days (40–50 μg/g by Day 7). Bone attained the greatest concentration of boron (2- to 3-fold over plasma levels) while levels in adipose tissue were 20% of plasma levels during the 7-day exposure period. All other tissues appeared to show no appreciable accumulation of boron over plasma levels. The data suggest that neither the apparent selective testicular toxicity nor the slight CNS hormonal effect associated with boric acid exposure can be explained on the basis of selective accumulation of boron in the testis or brain/hypothalamus, respectively. Thus, the testicular toxicity is likely the result of certain biological processes that are unique to the testis and which are targets of boron exposure.

Application of inductively coupled plasma emission spectroscopy to multielement analysis of foodstuffs used in metabolic studies

The concentrations of nine elements (Ca, Cu, Fe, K, Mg, Mn, Na, P, Zn) in selected food items from the four main food groups were determined simultaneously by inductively coupled argon plasma emission spectroscopy (ICAPES) after a nitric-perchloric (6:1) acid digestion procedure. The results indicate that, while most of the analyzed mineral values compare well with previously reported values, significant differences between the concentrations in some food items exist. Analyzed values generally appear lower than those found in food composition tables. Current methods quantitate elements previously not reported.

Material Characterization and Thermoforming of Polyethylene Terephthalate Film for Electrical Insulation

Differential scanning calorimetry (DSC) was used to determine as-received glass transition, crystallization, and melting temperatures of polyethylene terephthalate (PET). A Box-Behnken experimental design was used to evaluate the effect of form ing temperature, forming rate, and heat-set temperature on shrinkage, tear resistance, and thermal properties. At a forming temperature of 88°C and heat-set temperature of 180°C, good-quality PET parts were produced with an optimum forming time between 0.5 min and 5.0 min. In addition, inductively coupled argon plasma emission spectroscopy (ICAP) was used to determine the catalyst system for PET sheets obtained from two vendors.

Internal standard selection in the presence of matrix interactions in an inductively coupled argon plasma optimised for simultaneous multielement analysis by atomic emission spectrometry

Errors in element concentration measurement due to the effect of various matrix components have been reported in inductively coupled argon plasma emission spectroscopy (ICP-AES) analyses, optimised for simultaneous multielement determination. Two methods of correcting for these errors were examined by the use of six elements selected as internal standards, viz. As, Cd, Mn, Mo, Ni and Se. Both the usual internal standard ratio method and the analysis of covariance method were efficacious in reducing the influence of matrix components (K, Ca, NaSio 3, polymaleic acid (PMA) and diethylenetriaminepentaacetic acid (DTPA)) on analyte determination. Any one of As, Cd, Mn, Mo or Se could be used to correct for the main effects of NaSiO 3 and DTPA; Cd or Mo for K; but Cd + Mo + As are necessary to correct for Ca over the range used. Except for Al and Mg, element measurements could be corrected for PMA effects by Cd + Mo + Se.

Flow injection systems wiht inductively-coupled argon plasma atomic emission spectrometry: Part 2. The generalized standard addition method

In multicomponent analysis by inductively-coupled argon plasma emission spectrometry, the generalized standard addition method is useful in overcoming matrix and/or spectral interferences. As this method requires many standard additions, it becomes cumbersome when done manually if many elements are to be determined. By using a flow injection system, the standard addtion manipulations required can be significantly simplified and completed within a shorter period of time with much less sample material. A flow injection system with merging zones is used to demonstrate the method for analyses of a Ni/Cu/Zn standard and of alloys. The reproducibility of measurements of the injected sample, with or without additions of standards is always better than 99%. The results obtained compare well with those obtained by the manual procedure and also with those obtained by atomic absorption spectrometry.

Simultaneous Determination of Total Boron, Calcium, Copper, Iron, Magnesium/Manganese, Phosphorus, Potassium, and Zinc in Fertilizers by Inductively Coupled Argon Plasma Emission Spectroscopy

Abstract Nine elements (B, Ca, Cu, Fe, Mg, Mn, P, K, and Zn) were determined in 34 Magruder fertilizer standards by inductively coupled argon plasma (ICAP) emission spectroscopy. The total elemental concentrations found for each of the 9 elements compared favorably with known concentrations. Seventeen of the fertilizer samples were also extracted with ammonium citrate, and the phosphorus in the extract was determined by ICAP emission spectroscopy with good results compared with the known Magruder concentration for available phosphate. Concentrations of other elements (Al, Ba, Cd, Co, Cr, Na, Ni, Pb, Si, and Sr) were also obtained but were not verified.

Critical evaluation of a multi-element scheme using plasma emission and hydride evolution atomic-absorption spectrometry for the analysis of plant and animal tissues

An analytical scheme that uses inductively coupled argon plasma emission spectroscopy (ICAP) and hydride evolution atomic-absorption spectrometry (HEAA) for the determination of trace elements in plant and animal tissues has been evaluated. The scheme incorporates the ion-exchange procedure of Kingston et al., which uses Chelex 100 resin to concentrate trace elements and remove potentially interfering alkali and alkaline earth metals. The separation procedure is included in a scheme designed to maximise the number of analyte metals that can be determined from a single digestion of a biological matrix. Acid-digested samples are divided into two fractions. One fraction (5% of the total) is measured directly by ICAP for alkali and alkaline earth metals and phosphorus and for transition metals such as iron and manganese, which are not well behaved on the resin. The other fraction (95% of the total) is subjected to the separation procedure whereby a number of biologically important trace elements, including cadmium, copper, molybdenum, nickel, vanadium and zinc, are initially sequestered by the resin, and then stripped into a small volume of dilute nitric acid for ICAP measurement of the “matrix-free” analytes. Arsenic, selenium and antimony, which are not retained by the resin, are collected with the initial column effluent, acidified and determined by HEAA. The reliability of the scheme is influenced by the nature of the acid digestion procedure used to oxidise the organic matrix. The scheme was tested by analysis of ten National Bureau of Standards biological reference materials.

Multi-element analysis by inductively-coupled plasma emission spectrometry in animal diets and faeces containing chromium marker

A simple fusion method is given for the dissolution of chromium(III) oxide marker in animal diets and faeces. Chromium is determined by inductively-coupled argon plasma emission spectrometry and, for comparison, by flame atomic absorption spectrometry. The feasibility of simultaneous multi-element analysis is investigated. Data on interferences and recovery are presented.