General Applicability of High-Resolution Continuum-Source Graphite Furnace Molecular Absorption Spectrometry to the Quantification of Oligopeptides Using the Example of Glutathione

This communication introduces the first-time application of high-resolution continuum-source molecular absorption spectrometry (HR CS MAS) for the quantification of a peptide. The graphite furnace technique was employed and the tripeptide glutathione (GSH) served as a model compound. Based on measuring sulfur in terms of carbon monosulfide (CS), a method was elaborated to analyze aqueous solutions of GSH. The most prominent wavelength of the CS molecule occurred at 258.0560 nm and was adduced for monitoring. The methodological development covered the optimization of the pyrolysis and vaporization temperatures. These were found optimally to be 250 °C and 2250 °C, respectively. Moreover, the effect of modifiers (zirconium, calcium, magnesium, palladium) on the absorption signals was investigated. The best results were obtained after permanent coating of the graphite tube with zirconium (total amount of 400 μg) and adding a combination of palladium (10 µL, 10 g L−1) and calcium (2 µL, 1 g L−1) as a chemical modifier to the probes (10 µL). Aqueous standard samples of GSH were used for the calibration. It showed a linear range of 2.5–100 µg mL−1 sulfur contained in GSH with a correlation coefficient R2 > 0.997. The developed method exhibited a limit of detection (LOD) and quantification (LOQ) of 2.1 µg mL−1 and 4.3 µg mL−1 sulfur, respectively. The characteristic mass accounted for 5.9 ng sulfur. The method confirmed the general suitability of MAS for the analysis of an oligopeptide. Thus, this study serves as groundwork for further development in order to extend the application of classical atomic absorption spectrometry (AAS).

Determination of the heavy metal contents of frequently used herbal products in Pakistan

Purpose: To determine the heavy metal content of selected local and international herbal medicines sold for the treatment of various diseases in Pakistan. Methods: The different dosage forms of herbal medicines assessed were crude forms of syrups, gel, capsule, powder and tonic. Wet digestion method was used to prepare the herbal samples using nitric acid, and then analyzed for arsenic (As), cadmium (Cd), lead (Pb) and mercury (Hg), using MHS-15 mercury/hydride system and flame atomic absorption spectrometry (FAAS). Results: The investigated results displayed the Arsenic level (0.00 ppm to 0.580 ppm); Cadmium (0.001 ppm to 0.006 ppm); Lead (0.00 ppm to 1.078 ppm) and Mercury (0.001 ppm to 0.012 ppm). All results were found below the permissible limit of acceptability intake of the World Health Organization (WHO) and American Herbal Products Association (AHPA). The pH of the samples were in the range of 1.52 to 6.99. Conclusion: The findings reveal that the investigated herbal products available in Pakistan are safe with reference to heavy metals, and considered non-toxic for human consumption.

Determination of Mercury, Methylmercury and Selenium Concentrations in Elasmobranch Meat: Fish Consumption Safety

This study measures total mercury (THg), methylmercury (MeHg) and selenium (Se) concentrations in elasmobranch fish from an Italian market with the aim of evaluating the risk-benefit associated with their consumption, using estimated weekly intake (EWI), permissible safety level (MeHgPSL), selenium health benefit value (HBVSe) and monthly consumption rate limit (CRmm) for each species. THg and Se were analysed by atomic absorption spectrometry, while MeHg was determined by HrGc/Ms. THg and MeHg concentrations ranged from 0.61 to 1.25 μg g−1 w.w. and from 0.57 to 0.97 μg g−1 w.w., respectively, whereas Se levels were 0.49–0.65 μg g−1 w.w. In most samples European Community limits for THg were surpassed, while for MeHg none of the fish had levels above the limit adopted by FAO/WHO. EWIs for THg and MeHg in many cases were above the provisional tolerable weekly intakes (PTWIs). MeHgPSL estimate showed that fish should contain approximately 50% of the concentration measured to avoid exceeding the PTWI. Nevertheless, the HBVSe index indicated that solely skates were safe for human consumption (HBVSe = 3.57–6.22). Our results highlight the importance of a constant monitoring of THg and MeHg level in fish, especially in apex predators, to avoid the risk of overexposure for consumers.

Do the total mercury concentrations detected in fish from Czech ponds represent a risk for consumers?

Mercury is one of the important pollutants of the environment. Therefore, it’s necessary to monitor quantity of mercury especially in aquatic ecosystems. The main goal of the presented study was to compare the content of total mercury in tissues of fish coming from the Czech Republic, an important carp exporter, with focus on comparison of mercury content between 3 different ponds, its comparison between different fish species and between different tissues of the same species, and estimation whether the mercury content in tissues meets the limit given in the Commission Regulation (EC) No. 1881/2006 or not. Total mercury concentration was measured in 90 fish specimen sampled from three ponds (Velky Kocelovicky, Mysliv and Zehunsky) in autumn 2018. The values of total mercury in fish tissues was measured by atomic absorption spectrometry. The content of total mercury in the tissues decreased as follows: muscle > liver > gonads > scales. The highest average content of total mercury in muscle was 0.1517 ± 0.0176 mg/kg coming from pike caught in Velky Kocelovicky pond. In contrast, the lowest average content of total mercury in muscle 0.0036 ± 0.0003 mg/kg was found in carp tissue coming from the locality of Zehunsky pond. We confirmed that the predatory fish are more exposed to mercury than non-predatory fish. None of the monitored localities exceeded the set regulatory limit. Thus, our study shows that fish coming from these ponds are safe in terms of total mercury content.

Optimization of pineapple juice amount used as a negative oral contrast agent in magnetic resonance cholangiopancreatography

To evaluate the potential variability of Manganese (Mn2+) in commercial pineapple juice (PJ) produced in different years and to identify the optimal Mn2+ concentration in the correct amount of PJ to be administered prior to Magnetic Resonance Cholangiopancreatography (MRCP) in order to suppress the gastroduodenal (GD) liquid signal. The Mn2+ concentration in PJ produced in different years was defined using Atomic Absorption Spectrometry. The optimal Mn2+ concentration and the amount of PJ, were estimated in an in-vitro analysis, and were then prospectively tested in a population of patients who underwent MRCP. The results were compared with those achieved with the previous standard amount of PJ used in a similar population. The concentrations of Mn2+ in commercial PJ produced in different years did not differ. A total amount of 150 ml (one glass) of PJ having a high Mn2+ content (2.37 mg/dl) was sufficient for the suppression of the GD liquid signal, despite the additional dilution caused by GD liquids since it led to a final concentration of Mn2+ of 0.5–1.00 mg/dl. The optimized single-dose oral administration of 150 ml (approximately one glass) of PJ having a high Mn2+ concentration prior to MRCP was adequate to guarantee the correct amount of Mn2+ to suppress the GD signal.