Enhanced digestion of complex cosmetic matrices for analysis of As, Hg, Cd, Cr, Ni, and Pb using triton X-100.

A suitable optimized digestion method for lipsticks and powders for the analysis of As, Hg, Cd, Cr, Ni and Pb by Hydride Generation Atomic Absorption Spectrophotometry (HG-AAS), Cold Vapor Atomic Absorption Spectrophotometry (CV-AAS) and Flame Atomic Absorption Spectrophotometry (FAAS) was developed using common acid digestion methods enhanced by the use of Triton X-100. The three acid digestion methods used in this study were Method A (nitric acid and hydrogen peroxide), Method B (nitric acid and hydrochloric acid) and Method C (nitric acid, hydrochloric acid and hydrogen peroxide). Triton X-100 was added to each of these and the effects were studied. The acid digestion method that was determined to be the most suitable and efficient for lipsticks and powders was Method A-1 (nitric acid and hydrogen peroxide with 5% Triton X-100 at 95 °C for 3 h). The range of percentage recoveries obtained were; powders (98.50% to 92. 61%) and lipsticks (100.96% to 99.41%) for As, Cd, Cr, Pb, Hg and Ni. The addition of Triton X-100 significantly improved the efficiency of the method.•Triton X-100 improves the efficiency of acid digestion of fatty hydrophobic samples by dispersing the sample throughout the acid digestant.

Total and Estimated Inorganic Arsenic Levels in Imported and Local Chicken Sold in Trinidad and Tobago.

ABSTRACT: Arsenic contamination in chicken is a cause of concern because of the potential health problems that may arise. In Trinidad and Tobago, chicken consumption averages about 53.8 kg per person per year, and chicken accounts for 85% of all the meat consumed locally. Fourteen chicken samples of imported, locally grown, and local organically farmed chickens were obtained from poultry depots and local supermarkets and were analyzed in triplicate. The concentration of total arsenic in the imported chicken ranged from below the method detection limit (MDL) to 512.50 µg/kg, and the concentration in the locally produced chicken ranged between

Optimization of instrument conditions for the analysis for mercury, arsenic, antimony and selenium by atomic absorption spectroscopy.

The chemical vapor generation atomic absorption spectrometry technique is extremely popular for trace analysis specifically hydride generation continuous flow systems for arsenic, antimony, selenium and cold vapor for mercury. Optimizing the instrument parameters as well as the hydride generating reactions will improve the sensitivity and reliability of the results obtained. The advantage of optimizing these conditions increases the production of hydrides or vapor species formed thereby improving recoveries. In addition this helps to reduce chemical interferences from other species that may compete with the analyte of interest for hydride formation. Parameters optimized include: •Reagent flow rate•Sample flow rate•Argon flow rate•Acetylene/Air ratio•Concentration of reagents•Read delay time For the analytical procedure the flow rate of the reagents and sample was affected by the tension on the peristaltic pump and the size of the tubing. The optimized flow rate for all reagents was between 0.9-1.0 mL/min and between 6-7 mL/min for the sample when both conditions were applied. The optimized type and concentrations of the reducing agent for Arsenic, Antimony and Selenium were NaBH4 (0.6% w/v), NaBH4 (0.7% w/v) and NaBH4 (0.1% w/v) in NaOH (0.5% w/v) respectively and SnCl2 (25% w/v) in HCl (20% v/v) for Mercury. The concentration and type of acid that produced the optimum signals for Arsenic, Antimony and Selenium were 5, 10 and 10 mol/dm-3 respectively. The flow rates for the carrier gas (Argon) for Arsenic, Antimony, Selenium and Mercury were optimized at 0.2, 0.2, 2.0 and 2.0 mL/min respectively. The optimized flow rate for fuel gas (Acetylene) for all the metals except Mercury was 2.5 mL/min. The optimized Instrument Read Delay Time for Mercury was 70 s and 20 s for Arsenic, Antimony and Selenium.

Optimization of an acid digestion procedure for the determination of Hg, As, Sb, Pb and Cd in fish muscle tissue.

A simple, efficient and cost effective method was developed and optimized for the digestion of fish tissue for the determination of Lead, Cadmium, Mercury, Antimony, Arsenic and Selenium by FAAS, CVAAS and HGAAS. Three of the more common classical open tubed acid digestion procedures were explored with the purpose of optimizing the variables and selecting the single most efficient, convenient and inexpensive digestion method. The effect of parameters such as digestion media, digestion time and digestion temperature on the efficiency of extraction of heavy metals from fish tissue was examined. Concentrated nitric acid was determined to be the most efficient digestion media for all the metals studied. •Efficient extraction of Arsenic, Selenium, Antimony, Lead and Cadmium was achieved at a digestion temperature of 100 °C for 120 min.•Optimum extraction of Mercury in fish tissue was achieved at 85 °C for 120 min since at higher temperatures, mercury was lost due to volatilization.

Mercury, arsenic, cadmium and lead in two commercial shark species (Sphyrna lewini and Caraharinus porosus) in Trinidad and Tobago.

Sharks are long-lived apex predators which can accumulate toxic metals such as mercury and arsenic. Samples of Sphyrna lewini and Carcharinus porosus were collected from two commercial fish landing sites in Trinidad. Heavy metal concentrations were determined in the muscle, dorsal fin, vertebrae and liver using atomic absorption spectrometric. The provisional tolerable weekly intake (PTWI) and target hazard quotient (THQ) were determined to assess the potential health risks to consumers. Mercury levels ranged between 74-1899µg/kg in S. lewini and 67-3268µg/kg in C. porosus. Arsenic levels ranged between 144-2309µg/kg in S. lewini and 762-6155µg/kg in C. porosus. Cadmium levels generally ranged between 0.27-27.29mg/kg in S. lewini and 0.6-29.89mg/kg in C. porosus. Lead levels generally ranged between 0.14 and 208.81mg/kg in S. lewini while C. porosus levels ranged between 0.30 and 459.94mg/kg. The PTWI and THQ values suggest that consumption of these shark species can therefore be a major source of exposure to lead, cadmium, arsenic and mercury in humans and is likely to have potential health risk over long term exposure.

The evaluation of total mercury and arsenic in skin bleaching creams commonly used in Trinidad and Tobago and their potential risk to the people of the Caribbean.

Background. Skin lightening is very popular among women and some men of the Caribbean, and its popularity appears to be growing. The lightening of skin colour is done to produce a lighter complexion which is believed to increase attractiveness, social standing and improves one's potential of being successful. Design and Methods. Fifteen (15) common skin lightening creams found in pharmacies and cosmetic retailers throughout Trinidad and Tobago were evaluated for Mercury by Cold Vapor Atomic Absorption Spectrophotometry (CVAAS) and Arsenic by Hydride Generation Atomic Absorption Spectrophotometry (HGAAS). The results obtained were compared to global standards and previous research. Results. Fourteen (14) of the fifteen samples analysed contained Mercury in the range of 0.473 λg/g to 0.766 λg/g. One sample had a Mercury content of 14,507.74±490.75 λg/g which was over 14,000 times higher than the USFDA limit for mercury in cosmetics of 1 λg/g. All samples contained Arsenic in the range 1.016 λg/g to 6.612 λg/g, which exceeds the EU limit for cosmetics of 0 λg/g. Conclusions. All the samples analysed contained significant amounts of Mercury and Arsenic and none of them can be considered safe for prolonged human use. The samples that contained Mercury levels which were lower than the USFDA limit contained Arsenic levels which exceeded the EU standard of 0 λg/g in cosmetics. The popularity of these skin lightening creams in the Caribbean region places the population at elevated risk of chronic Mercury and Arsenic poisoning and possibly acute Mercury Poisoning.

Yeast-generated CO2:A convenient source of carbon dioxide for mosquito trapping using the BG-Sentinel?traps

Objectives: To evaluates carbon dioxide (CO2) production from yeast/sugar mixtures and its efficiency as an attractant in BG-Sentinel traps. Methods: The rate of CO2production was optimized for different yeast/sugar mixtures. The optimized mixture was then used as bait in BG-Sentinel traps.The efficiency of this bait was then compared to octenol baited traps. Results: The yeast/sugar(5 g:280 g)in 300 mL water generated the highest volume of CO2. The CO2baited traps caught significantly more mosquitoes than octenol baited traps. Conclusions: Yeast-produced CO2can effectively replace octenol baits in BG traps. This will significantly reduce costs and allow sustainable mass-application of the CO2 baited traps in large scale surveillance programs.