Electrochemical detection of mercury, cadmium, lead, and copper using boron -doped diamond electrodes

Anodic stripping voltammetry (ASV) and boron-doped diamond (BDD) electrodes were used to detect mercury, cadmium, lead, and copper at low part-per-billion (ppb) concentrations. Two types of BDD electrodes were used, free-standing polished electrodes, and unpolished BDD films grown on silicon substrates. The electrochemical detection of mercury was difficult in all of the matrices investigated: nitrate, chloride, thiocyanate, phosphate, and sulfate. Precipitation of mercuric or mercurous salts on the electrode surface was the likely cause. The addition of an auxiliary element improved the detection of mercury. The detection of cadmium and lead was more straightforward. The addition of copper improved the detection of lead, but not cadmium. The BDD electrode was used to determine the complexing capacity of a river water sample for lead. The application of ultrasound during the deposition step of ASV improved the detection of cadmium, but eventually damaged both types of BDD electrodes

Determination of macro, essential trace elements, toxic heavy metal concentrations, crude oil extracts and ash composition from Saudi Arabian fruits and vegetables having medicinal values

The concentrations of essential elements (Mg, Ca, Na, K, Fe, Zn, Se, Al, Ni, and Cu) and toxic heavy metals (Pb, As, Cr, Cd, and Cr) from Saudi Arabian fruits and vegetables were determined by inductively coupled plasma optical emission spectrophotometry (ICP/OES). Two types of butters, Caralluma munbayana and Caralluma hesperidum, Vigna (Vigna unguiculata), common fig (Ficus carica), Annona seeds (Annonaceae seeds), Annona fruits (Annonaceae fruits), Fennel (Foeniculum vulgare), and Fennel flowers (Nigella sativa) were investigated, because they are used by indigenous groups as traditional medicines with Soxhlet-extraction and dry-ashing protocol. The estimated daily dietary element intake in food samples was further calculated in order to evaluate the element dietary intake and fruit and vegetable consumption pattern of the indigenes of Saudi Arabia. The crude oil and ash compositions varied widely, but suggested that most of the foods were good sources of oils and minerals. The figures-of-merit of the ICP-OES calibration curves were excellent with good linearity (R2 > 0.9921). The use of ICP-OES in this study allowed the accurate analysis and the detection of the elements at low levels. Essential elements (K, Ca, Na, and Mg) had the highest concentrations while toxic heavy metals (As, Pb, and Cd) had the lowest in the foods. Essential element pairs (Mg-Na, Mg-Ca, Fe-Al) were highly correlated, suggesting that these foods are sources of multiple nutrients. Toxic element pairs (Pb-Cd, Pb-As, and Cd-As), however, were poorly correlated in the foods, suggesting that these elements do not have a common source in these foods. Average consumption of these foods should provide the recommended daily allowances of essential elements, but will not expose consumers to toxic heavy metals. The ICP-OES method was validated by determining method detection limits and percent recoveries of laboratory-fortified blanks, which were generally 90–100%

Determination of non-toxic and potentially toxic elements concentration and antioxidant capacity in selected natural and essential oils with high market values

<p>Natural oils (NOs) and essential oils (EOs) are widely used in the food and beverage, medical, aromatherapy and cosmetic industries, but little is known about their elemental composition or antioxidant ability. Microwave-assisted acid digestion and inductively coupled plasma-optical emission spectroscopy were used to determine the non-toxic elements (Al, Ca, Cu, Fe, K, Mg, Na, Se and Zn) and potentially toxic elements (As, Cr, Cd, Mn, Ni and Pb) concentrations in 13 selected NOs and EOs. The per cent recoveries of laboratory-fortified blanks analysed for quality control were 94–110%. The elemental concentrations varied widely in NO and EO samples, as demonstrated by the large standard deviation obtained for some elements. The average levels of non-toxic elements (Al (14.5 ± 3.7 μg/g); Ca (278 ± 138 μg/g); Cu (7 ± 14 μg/g); Fe (16 ± 5 μg/g); K (36 ± 31 μg/g); Mg (56 ± 27 μg/g); Na (266 ± 277 μg/g); Se (0.7 ± 0.3 μg/g) and Zn (6.1 ± 2.6 μg/g)) were determined in NOs and EOs. Comparatively, low levels of potentially toxic elements (As (0.1 ± 0.2 μg/g); Cd (0.1 ± 0.0 μg/g); Cr (0.2 ± 0.1 μg/g); Mn (0.8 ± 0.1 μg/g); Ni (4.5 ± 2.2 μg/g); and Pb (0.3 ± 0.2 μg/g)) were obtained in the oils. Principal component analysis (PCA) revealed that the first two principal components explained 100% of the variability in the elemental concentrations. Na, Ca, Mg and K were the main contributors to PCA. Non-toxic element pairs were strongly correlated (<i>R</i>² > 0.9440) indicating a common source in these oils, but toxic element pairs were poorly correlated. Although toxic element concentrations were low, routine monitoring in oils is recommended. The antioxidant ability of NOs and EOs to potentially reduce free radicals, which are often involved in several degenerative diseases, such as ageing, stroke, diabetes and cancers was determined by DPPH (2,2-di(4-<i>tert</i>-octylphenyl)-1-picrylhydrazyl) free radical scavenging assay and ultraviolet-visible spectroscopy. Jasmine, castor and tea tree lemon oils were the best antioxidants. The oils in this study have the potential to replace artificial antioxidants used in foods, cosmetics and other products.</p

Clinical Characteristics by sex and <i>5HTR2C</i> rs6318 Ser23 C and Cys23 G allele.

<p>^a p-value derived from unadjusted linear model;^b p-value derived from age-adjusted logistic regression model;^c p-value derived from age-adjusted linear model;^d p-value was derived from age-adjusted ordinal logistic regression model with number of diseased vessels modeled as an ordinal variable ranging from 0 to 3. Note. </p

Cox regression models predicting death or non-fatal myocardial infarction (N = 6,126, N events = 1,769).

<p> Note: The model including adjustment covariates included all predictors simultaneously.</p

Kaplan-Meier curves illustrating the risk of death or myocardial infarction for each rs6318 genotype in Women (panel a) and Men (panel b).

<p>Using pre-specified contrasts in a Cox regression model adjusted for covariates, differences were statistically significant when comparing: male Ser23 C hemizygotes and female Ser23 C homozygotes to all Cys23 G carriers (p  = .005); male Ser23 C hemizygotes to male Cys23 G hemizygotes (p  = .022), and female Ser23 C homozygotes to female Cys23 G carriers (p  = .024).</p

The neighbourhood context of urban Aboriginal crime

This article addresses Carol La Prairie's (1992; 2002) hypothesis that the over-representation of Aboriginal people in the Canadian criminal justice system is, to a considerable extent, due to their disadvantaged urban living conditions. Specifically, it investigates the sources of the high level of policereported Aboriginal crime in Winnipeg in 2001. Geocoded crime incident data from the incident-based Uniform Crime Reporting Survey and Census data for the City of Winnipeg are combined in a neighbourhood-level ecological analysis of urban Aboriginal crime. The results indicate that a substantial part of the elevated level of police-reported Aboriginal crime is explained by the structural characteristics of the neighbourhoods in which Aboriginal people tend to live. These results confirm La Prairie's hypothesis and point to the importance of considering community conditions in understanding and preventing crime