Quantification of Platinum in Edible Mushrooms Using Voltammetric Techniques

Edible mushrooms are a food source with interesting nutritional values. The chief objective of this research was to develop a consistent method for the quantitative ultra-trace analysis of Pt in mushrooms, which is complex because it cannot be readily quantified by common analytical procedures. This research is one of the first analytical methods to establish Pt amount in these vegetables. In this research, 28 different edible mushroom samples from Italy were investigated. Determination of Pt in mushrooms was completed using Differential Pulse Voltammetry (DPV). In this study, we applied the standard addition method because there are no certified reference mushrooms containing platinum group elements on the market. The platinum quantification limit was 0.03 µg kg−1 d.w. In the analyzed samples, platinum amount was in the range of 0.03–73 µg kg−1. Our mushroom samples had a Pt content lower than the concentrations recommended by international establishments for other foodstuffs. In the future, the optimized method could be used for the analysis of plant and animal matrices intended for food supply.

The magnetic stir bar as a source of impurities in laboratory blank solutions of the environmental samples subjected to microwave-assisted acid digestion

Teflon-coated magnetic stir bars are suspected to be a source of impurities for the laboratory blank solutions. To evaluate the ability of magnetic bars to absorb and release different elements at sub-ppb and above-ppb (µg L-1) level the experiment with new and used bars was conducted. The bars were subjected to microwave-assisted acid digestion with the soil sample and a series of successive cleaning procedures. The ICP-OES/MS analysis of the obtained extracts revealed that most of the elements may be released during subsequent extractions in the ppb-level concentrations, whereas the following elements: Cr, Cu, Sb, Sn, and Pb may be extracted even in elevated concentrations. SEM/EDS inspection of Teflon surfaces demonstrated the multiple defects that probably increase the absorption of the elements. We concluded that the concentration of mineral impurities in the laboratory blank solution prepared in the randomly selected one vessel per sample preparation batch is hardly propagated to the other used vessels. The alternative concept "blank per vessel" was proposed especially for ultra-trace analysis. Also, an additional step in the bar washing procedure was proposed.

Reliable Ultra Trace Analysis of Cd, U and Zn Concentrations in Greenland Snow and Ice by Using Ultraclean Methods for Contamination Control

This study presents ultraclean procedures used in the challenging task of determining trace elements at or below the pg/g concentration level encountered in Greenland snow and ice. In order to validate these ultraclean procedures, recent snowfall and Holocene ice from northwest Greenland were analyzed for Cd, U, and Zn concentrations. The total procedural blanks brought through the entire measurement procedure proved to be negligible, compared to trace element concentrations, measured in snow and ice samples. This validates the overall practicality of the proposed ultraclean procedures, thereby ensuring the reliable measurements of ultra-trace analysis. A comparison between our study and published data shows that improper procedures employed throughout all stages, from field sampling to analysis to elevate the concentrations by several orders of magnitude, relative to the reliable concentration ranges. The risk of contamination exposure for selected trace elements appears to increase in the order of U < As ≤ Pb < Cd < Zn. Reliable measurements of Cd, U, and Zn concentrations in snow and ice allowed us to interpret the data in terms of seasonal variations in the inputs of crustal and anthropogenic sources to Greenland ice sheet.