waste silica sources as heavy metal stabilizers for municipal solid waste incineration fly ash

Abstract The present work discusses a new method, based on the use of silica fume, for heavy metal stabilization. The inertization procedure is reported and compared with other technologies, involving the employ of amorphous silica as stabilizing agent for municipal solid waste incinerator fly ash treatment (i.e. colloidal silica and rice husk ash). The obtained final materials are characterized in terms of chemical composition and phase analysis. The reported method, realized at room temperature, employs all waste or by-product materials. As a consequence it appears to be economically and environmentally sustainable

Possibilities and drawbacks of total reflection X-ray fluorescence spectrometry as a fast, simple and cost-effective technique for multielement analyses of cosmetics

This paper shows a simple, rapid and cost-effective method for multielement analyses of cosmetics. Total reflection X-ray fluorescence spectrometry (TXRF) is used to determine the composition, particularly the presence of potentially toxic elements, of cosmetics. Three sample preparation methods based on suspension preparation were developed for different types of cosmetic samples, e.g. lipsticks, eye shadows and body creams. Limits of detection within the low mg kg1 range were obtained and enabled cosmetic screening for compliance with the legal thresholds for some major toxic elements. A good accuracy of the results on a wide range of concentration levels (>10000mg kg1) was found without the need of sample dilution. Results obtained for most elements in the lipstick and cream samples agreed with those obtained by the reference method recommended by the Food and Drug Administration, based on using inductively coupled plasma techniques after microwave digestion. However, for eyeshadow analysis, a more sophisticate approach is needed to improve the analytical results

Procedure optimization of type 304 and 420B stainless steels release in acetic acid

Stainless steel has always been considered suitable for food contact, even though it has been demonstrated that this material has the tendency to release metal ions when used in food contact applications. In this study, the testing procedure for metal release in simulated food contact proposed by the Italian Ministerial Decree 21.03.1973 highlighted some critical aspects that needed to be improved such as the surface finishing, solution composition and volume, and reproducibility. AISI 304 austenitic and AISI 420 type B martensitic stainless steels were chosen to optimize the parameters of test procedure for release of Chromium, Nickel and Manganese. The effects of the steel chemical composition, the material fabrication cycle and the testing method on metal release were evaluated. Considering the achieved results, a list of suggestions is proposed for the improvement of the Italian law

Elemental analysis of teas, herbs and their infusions by means of total reflection X-ray fluorescence

This work shows that total reflection X-ray fluorescence (TXRF) is a suitable tool for multi-elemental analysis of teas, herbs and their infusion. A low power benchtop TXRF spectrometer was used. Safety of infusion consumption was evaluated. Many commercially available teas,herbs and roots samples were analyzed. Total concentrations of thirteen elements K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Rb, Sr, Ba and Pb as well as their extraction efficiencies into infusion were determined. The content of Pb is highlighted in all teas and herbs, in the concentration range between 0.5 and 4.8 mg/g, but only in infusions of herbs. Chemometry was applied for classification purposes. Elemental daily intakes with respect to infusion drinking was calculated and compared with dietary reference intake values. Results show that TXRF is a fast and simple technique for safety check of tea and herb infusions on a routine basis

Total reflection X-ray fluorescence used to distinguish mechanically separated from non-mechanically separated meat

This paper presents the successful application of total reflection X-ray fluorescence spectroscopy (TXRF) for the identification of products obtained from mechanically separated meat (MSM), a very important issue for food quality and safety. According to the European Food Safety Authority, one of the most important parameters to distinguish MSM is the content of Ca. Consequently, the development of reliable and cost-effective analytical tools is very important to monitor the chemical composition of these foods. In this study, we have developed an analytical method for elemental analysis of meat samples based on total reflection X-ray fluorescence. A simple sample preparation by suspending the grinded meat sample in a solution of diluted Triton X-100 and polyvinyl alcohol in water showed to be the best for this kind of samples. Fresh chicken meat, chicken meat with different percentage of MSM, pure MSM and meat products prepared with MSM were analyzed. The content of K, Ca, Fe, Cu and Zn was determined. Results show that Ca, but also K and Fe are significant markers to distinguish MSM from fresh meat. A limit of 40% MSM for differentiation was achieved by applying principal component analysis. The method accuracy was evaluated comparing the obtained results with those obtained after acidic digestion and ICP-MS analysis

Study of metal release from stainless steels in simulated food contact by means of total reflection X-ray fluorescence

This study shows a reliable procedure to prescribe the preferential use of a material for food contact. Release tests with optimized parameters were performed on six different stainless steel accepted for the use in food contact: AISI 420, AISI 430, AISI 202, AISI 303, AISI 304, and AISI 316. Total reflection X-ray fluorescence spectroscopy was used to measure the concentration of Cr, Mn and Ni in contact solutions from release tests. Results show that AISI 202 and 430 release the lowest amount of Mn, Cr and Ni. While, AISI 420 is the worst material, exceeding the limit set in the Italian regulation for all the three metals of interest. One sample was selected to test the reproducibility of TXRF measurements performed in three different laboratories around the world. Results show that quantitative analyses by means of TXRF satisfy the requirements of this field of application

Study of metal release from stainless steels in simulated food contact by means of total reflection X-ray fluorescence

This study shows a reliable procedure to prescribe the preferential use of a material for food contact. Release tests with optimized parameters were performed on six different stainless steel accepted for the use in food contact: AISI 420, AISI 430, AISI 202, AISI 303, AISI 304, and AISI 316. Total reflection X-ray fluorescence spectroscopy was used to measure the concentration of Cr, Mn and Ni in contact solutions from release tests. Results show that AISI 202 and 430 release the lowest amount of Mn, Cr and Ni. While, AISI 420 is the worst material, exceeding the limit set in the Italian regulation for all the three metals of interest. One sample was selected to test the reproducibility of TXRF measurements performed in three different laboratories around the world. Results show that quantitative analyses by means of TXRF satisfy the requirements of this field of application

TXRF analysis of vegetal foodstuff samples

In this work, a fast and simple analytical method has been developed for the multi elemental analysis of different vegetal foodstuff samples, by using a combination of two low power benchtop total reflection X-ray fluorescence (TXRF) systems. The suspension of the powdered samples in deionized water showed to be the most suitable way for the preparation and analysis of this kind of samples. However, for comparison purposes the samples were also acid digested and measured by TXRF

Comprehensive approach to the validation of the standard method for total reflection X-ray fluorescence analysis of water

In this work, we present the validation of the chemical method for total reflection X-ray fluorescence (TXRF) analysis of water, proposed as a standard to the International Standard Organization. The complete experimental procedure to define the linear calibration range, elements sensitivities, limits of detection and quantification, precision and accuracy is presented for a commercial TXRF spectrometer equipped with Mo X-ray tube. Least squares linear regression, including all statistical tests is performed separately for each element of interest to extract sensitivities. Relative sensitivities with respect to Ga, as internal standard, are calculated. Accuracy and precision of the quantification procedure using Ga as internal standard is evaluated with reference water samples. A detailed discussion on the calibration procedure and the limitation of the use of this method for quantitative analysis of water is presented