Assessment of Levels of V, Cr, Mn, Sr, Cd, Pb and U in Bovine Meat

Pollution of the environment with heavy metals can be a serious problem. In South Africa, particularly, there are many sources of heavy metals, often due to smelter and mining activities. This has led to toxic metals in the environment that directly affect air, water and food. The presence of heavy metal residues in foodstuffs is potentially hazardous to humans and animals. Heavy metals accumulate in certain organs, particularly in the liver and kidney. The objective of this study was to determine the levels of V, Cr, Mn,Sr, Cd, Pb andUin bovine organs and tissues obtained from polluted areas of North West Province, South Africa. Bovine liver, kidney, muscle, fat and bone samples were freeze-dried, homogenized and mineralized using a microwave-assisted digestion system. The levels were quantified using dynamic reaction cell inductively coupled plasma mass spectrometry(DRC-ICP-MS).A bovine muscle (NIST-RM8414) and bovine liver, reference material (NIST-RM1577b), were also analyzed and results agreed with certified values. The study revealed accumulation of Sr in bone, Cd, Pb and U in kidney and bone, Mn in liver and, V and Cr in kidney tissues of cattle.Keywords: Bovine meat, heavy metals, DRC-ICP-M

Evaluation of Six Sample Preparation Methods for Determination of Trace Metals in Lubricating Oils Using Inductively Coupled Plasma-Optical Emission Spectrometry

Quantification of trace elements in used lubricating oil forms a vital part in monitoring engine conditions and impact on the environment. In this study, inductively coupled plasma-optical emission spectrometry (ICP-OES) was employed for the determination of Ag, Ba, Cu, Mn and Ni in used lubricating oils. Methodology was developed so as to minimize the oil’s carbonaceous matter and its effect on viscosity.Accordingly, six oil sample preparation techniques (xylene dilution, detergent emulsion, microwave digestion, dry-ashing, wet-ashing and ultrasonic extraction) were investigated for their efficiency. Optimization of the factors influencing ultrasonic-assisted extraction and ICP-OES operating parameters enabled quantification of the trace metals in oils. Limits of detection (3Sb/m), in the ng g–1 range, were obtained for each element of interest using each method investigated. The validity of the methodologies studied was confirmed through the analysis of quality control (QC) samples. Analyte recoveries, ranging from 48.3 to 106 %, were obtained. Evaluation of the analytical methods studied with regard to accuracy, precision, LOD, linearity, applicability for routine analysis, preparation time and cost was made. Based on these evaluations, ultrasonic extraction has a clear advantage in terms of accuracy, applicability for routine analysis, time and cost of sample preparation.KEYWORDS Lubricating oil, ICP-OES, optimization

Internal Standard Method for the Determination of Au and some Platinum Group Metals Using Inductively Coupled Plasma Optical Emission Spectrometry

A method is described for the determination of Au, Pt, Pd, Ru and Rh in a converter matte sample, using inductively coupled plasma optical emission spectrometry (ICP-OES), with Y or Sc as internal standard. The results obtained by this method are discussed and compared with values obtained by an independent laboratory. The efficiency of internal standardization was evaluated by varying the operating conditions of the ICP-OES. Changes in the amount of energy transferred from the plasma to analyte, the amount of aerosol reaching the plasma and analyte residence time, were studied in terms of their effect on the emission intensity of the analyte and the internal standard. It was found that changes in the emission signals of the PGMs due to power variations could be effectively compensated for, using either Sc, Y or Ar lines as internal standards. For variations in aerosol gas flow rate, both Sc and Y could only compensate for Pd and Au between flow rates of 0.60 and 0.80 l min -1 and for Pt, Ru and Rh at 0.80 l min -1. The effect of sodium on the determination of Au and the PGMs, and the use of Sc and Y as internal standards, to compensate for Na matrix effects on accuracy were also studied. It was found that emission intensities of the analytes decreased with increasing Na concentration. Furthermore, Sc as an internal standard could compensate for Pt, Ru and Rh up to 5 g l-1 Na, while Y could only compensate for the same elements up to 1 g l -1 Na. South African Journal of Chemistry Vol.55 2002: 72-8

Impact of Metals on Secondary Metabolites Production and Plant Morphology in Vetiver Grass (Chrysopogon zizanioides)

The impact of selected metals on the production of phenolic compounds was investigated in a pot trial experiment. One-month old vetiver grass (Chrysopogon zizanioides) seedlings were exposed to different concentrations (0, 10, 50, 100, and 500 ppm) of As, Cr, Cu, Fe, Ni, Pb and Zn. All the plants except for those treated with As tolerated up to 500 ppm as they did not show any signs of stress such as wilting or necrosis. A significant decrease (>35 %) in the length of the plants treated with As, compared to the control, was observed at 50 ppm which further decreased with increasing As concentration. A serious case of phytotoxicity was observed at 500 ppm As as the plant could not survive. Total soluble phenolics content in vetiver plants increased with increasing concentration of metals in the growth medium. The amount of the cell wall-bound phenolics (2.01 to 5.84 mg GAE g–1 DW) was higher than the total soluble phenolics (1.13 to 2.14 mg GAE g–1 dry weight DW) and both increased with increasing metal concentrations. Morphological changes associated with metal-induced stress were also examined with a scanning electron microscope which revealed thickened cell walls, loss of cell shape, reduction of intercellular space and the closure of stomata in leaves of metal-exposed plants.Keywords: Vetiver grass, toxic metals, phytotoxicity, phenolic compounds, morphological change

Potentiometric Determination of Free Chloride in Cement Paste – an Alternative Method for Low-Budget Laboratories

Corrosion of rebar in concrete is commonly associated with, and to a large degree influenced by, the free chloride concentration in the pore water. The amount of chloride in concrete is important because chloride can promote corrosion of steel reinforcement when moisture and oxygen are present. A potentiometric procedure that makes use of direct measurement with a chloride ion selective electrode has been developed to analyze free chloride in the pore water extracted from cement paste.16 The accuracy and reliability of this analytical technique has been checked against a certified reference material, Merck sodium chloride solution. Confidence levels (CL0.95), of 0.03 and relative standard deviations of 0.2 % for chloride were determined for ordinary Portland cement (OPC) chloride binding capacity.Keywords: OPC, free chloride, potentiometr

Determination of selected phthalate esters compounds in water and sediments by capillary gas chromatography and flame ionization detector

The presence of phthalate esters (PAEs) in the environment is not desirable and therefore, needs to be monitored. This study reports the first data on the concentration levels of PAEs in water and sediments of the Jukskei River catchment area, South Africa. The study was conducted during the summer and winter seasons of 2005. Liquid-liquid extraction (LLE) and Soxhlet extraction (SE) methods were optimized, evaluated and used to determine PAEs of interest in water (unfiltered and filtered) and sediments samples, respectively. Mean percentage recoveries in spiked doubly distilled water ranged from 100 ± 5.32 dimethyl phthalate (DMP) – 122 ± 0.46 di-2-ethylhexyl phthalate (DEHP) and 91.6 ± 1.93 diethyl phthalate (DEP) – 117 ± 4.80 dibutyl phthalate (DBP) in sediments. The concentration levels of PAEs studied in unfiltered environmental water samples were in the range of 0.04(± 0.00) (DMP) − 9.76(± 00.1) ng mL−1(DEHP) for PAEs and from 0.09 (± 0.01) (DMP) – 4.38 (± 0.06) ng mL−1(DEHP) for filtered environmental water samples. Concentration levels obtained in sediments were from 0.05 (0.00) (DMP) – 4910 (0.36) ng/gdw (DEHP). PAEs adsorbed on the sample bottle gave concentration levels of up to 0.10 (± 0.03) ng mL−1for some samples and no analyte was detected (ND) in some cases Generally, concentrations obtained were below the water quality guideline values of United States Environmental Protection Agency (USEPA)

Determination of selected organochlorine pesticide (OCP) compounds from the Jukskei River catchment area in Gauteng, South Africa.

Organochlorine pesticides (OCPs) are continually detected in the environment due to their increasing applications in agriculture and industry. The presence of OCPs in the environment is not desirable since they are well known to have negative impact in humans, animals and birds. Thus, there has been a continual demand to monitor the presence of OCPs within the environment. Liquid-liquid extraction (LLE) and Soxhlet extraction (SE) methods (using dichloromethane as the extracting solvent,) were optimised and evaluated for the determination of these compounds in surface water (unfiltered and filtered) and sediment samples. The crude extracts obtained were subjected to column chromatography for clean-up. Thereafter, 1 µℓ of the cleaned extracts were injected into the GC equipped with ECD. Percentage recoveries obtained for OCPs ranged from 98.90±7.32 (2,4'-DDE) - 124.1±8.23 endosulfan II (ENDO II) % and from 98.99±5.30 (2,4'-DDE) - 121.1±0.38 (4,4'-DDE) % in spiked triply distilled water and sediment samples respectively. The levels of OCPs obtained in unfiltered environmental water samples ranged from 0.631±0.03 (γ-HCH) - 1 540±0.19 ng·mℓ-1 (4,4'-DDT) while levels in filtered water samples ranged from 0.895±0.01 (γ-HCH) - 9 089±0.08 ng·mℓ-1 (HEPTA). Levels of analysed OCPs obtained in sediments ranged from 0.266±0.01 (δ-HCH) - 22 914±2.85 ng·gdw-1 (2,4'-DDE). Analytes adsorbed on the sample bottles used for water samples collection gave levels which ranged from 0.01±0.01 - 1.06±0.02 ng·mℓ-1 for OCPs. The levels obtained from the catchment were significantly higher than the water criteria values recommended by USEPA and DWAF for the protection of the aquatic environment. Levels obtained were also higher than those of other studies conducted so far in South African aquatic environments. There is, therefore, a definite pollution of the Jukskei River catchment by the OCPs studied

Levels of selected alkylphenol ethoxylates (APEs) in water and sediment samples from the Jukskei River catchment area in Gauteng, South Africa.

There has been a continual search to develop sensitive analytical methods for detecting and determining organic compounds such as alkylphenol ethoxylates (APEs) in environmental samples, since they occur at very low concentration levels. Studies conducted so far in some South African waters have offered little or no information on APEs. The presence of these compounds in environmental samples is not desirable and therefore, needs to be monitored. Water and sediment samples were collected from different sites in the Jukskei River catchment area in the 2005 summer and winter seasons. Liquid-liquid extraction (LLE) and Soxhlet extraction (SE) methods (using 1:1 dichloromethane and methanol as extracting solvents) were optimised, evaluated and used to determine APEs of interest in water (unfiltered and filtered) and sediment samples, respectively. Mean percentage recoveries obtained for APEs in spiked double-distilled water were between 83.1±1.0 (OPnEOS3) and 108.1±3.5 (OP) and for sediments the range was between 96.6±0.9 (OPnEOS1) and 117.1±0.6 (OPnEOS3). The concentration levels of APEs studied in unfiltered environmental water samples were in the range of 0.25(0.03) ng/mℓ (NP) to 92.7(1.11) ng/mℓ (OPnEOS3) and 0.31(0.02) ng/mℓ (NP) to 60.1(0.51) ng/mℓ (OPnEOS3) for filtered environmental water samples. Concentration levels obtained in sediments were from 1.94(0.14) ng/gdw to 941(0.50) ng/gdw (OPnEOS3). Analytes adsorbed on the sample bottle gave concentration levels which ranged from 0.02(0.02) ng/mℓ to 0.42(0.02) ng/mℓ for APEs. All the compounds studied were found at levels higher than the European Union (EU) set levels for the protection of the aquatic environment

Multi-element determinations of N,N-dimethylformamide (DMF) coal slurries using ICP-OES

a b s t r a c t A slurry nebulisation technique was applied for elemental analysis of bituminous coals SARM 18, SARM 19 and four coals from three different seams in Witbank, South Africa, by inductively coupled plasma optical emission spectroscopy (ICP-OES). Major elements (Al, Ca, Fe, Mg, S, Si and Ti) and trace elements (Ba, Cr, Mn, Ni, Sr, V, Zn and Zr) in coal were determined. Various slurry preparations were evaluated using two dispersants (glycerol and Triton X-100) and by varying the concentration of dispersants, between 0.1% and 1.0% (v/v). The effect of initially solubilising the ground coal in N,N-dimethylformamide (DMF) was investigated by varying the volume of DMF added. The effect of wet grinding with DMF was investigated. Wet grinding with DMF was shown to drastically reduce particle sizes (50.0% < 0.28 lm and 90.0% < 6.17 lm) as compared to dry grinding (50.0% < 5.25 lm and 90.0% < 11.1 lm). The reduced particle sizes and increased transport efficiency of the coal slurries led to improved analytical recoveries of elements in the reference coal, SARM 18. The best analytical recoveries for all elements were achieved using 0.1% Triton X-100 with 10.0% DMF. Results obtained by ICP-OES after wet grinding of the coal with DMF, using 0.1% Triton X-100, also gave excellent recoveries (Al, 100%; Ca, 103%; Cr, 106%; Fe, 102%; Mg, 100%; Mn, 104%; Ni, 109%; Si, 102%; Ti, 95.0%; and V, 108%). The results obtained with 10.0% DMF and 0.1% Triton X-100 were in agreement with certified values for all selected elements according to paired t-test at the 95.0% confidence level. Selected elements (Al, Ca, Fe, Mg, Mn, Si, Ti and V) were also analysed with X-ray fluorescence for comparison with results obtained from ICP-OES. Analysis by ICP-OES of microwave digested coal was also carried out. It is suggested that the DMF slurry technique could be used for routine analysis of bituminous coals

The Use of Dowex-M43 Ion-exchange Resin in the Determination of Pt and Pd in Converter Matte by ICP-OES

The method of choice for the separation of platinum group metals (PGMs) from base metals and easily ionizable elements (EIEs) is usually ion-exchange. This paper describes an anion-exchange procedure using Dowex-M43 for the separation of EIEs in geological samples (converter matte) from PGMs and Au.Aqueous commercial standards were used to study the adsorption capacity of the Dowex-M43 resin for both Pd and Pt metals (0–1000 μgmL–1). The concentrations of Pd and Pt were determined using inductively coupled plasma optical emission spectroscopy (ICP-OES). The results from the analysis of solutions prepared from commercial standards after ion-exchange treatment showed quantitative recoveries of both Pt (97%) and Pd (99%) from Dowex-M43 resin using 0.1 mol L–1 thiourea solution. Good agreement was observed between results obtained in this method and those obtained with the use of the conventional acid dissolution method for the determination of Pd and Pt in converter matte.Keywords: Anion-exchange, converter matte, ICP-OES, platinum group metal