Determination of Total Silicon and SiO2 Particles Using an ICP-MS Based Analytical Platform for Toxicokinetic Studies of Synthetic Amorphous Silica.

Synthetic amorphous silica (SAS), manufactured in pyrogenic or precipitated form, is a nanomaterial with a widespread use as food additive (E 551). Oral exposure to SAS results from its use in food and dietary supplements, pharmaceuticals and toothpaste. Recent evidence suggests that oral exposure to SAS may pose health risks and highlights the need to address the toxic potential of SAS as affected by the physicochemical characteristics of the different forms of SAS. For this aim, investigating SAS toxicokinetics is of crucial importance and an analytical strategy for such an undertaking is presented. The minimization of silicon background in tissues, control of contamination (including silicon release from equipment), high-throughput sample treatment, elimination of spectral interferences affecting inductively coupled plasma mass spectrometry (ICP-MS) silicon detection, and development of analytical quality control tools are the cornerstones of this strategy. A validated method combining sample digestion with silicon determination by reaction cell ICP-MS is presented. Silica particles are converted to soluble silicon by microwave dissolution with mixtures of HNO3, H2O2 and hydrofluoric acid (HF), whereas interference-free ICP-MS detection of total silicon is achieved by ion-molecule chemistry with limits of detection (LoDs) in the range 0.2-0.5 µg Si g-1 for most tissues. Deposition of particulate SiO2 in tissues is assessed by single particle ICP-MS.

Blood thiamine, zinc, selenium, lead and oxidative stress in a population of male and female alcoholics: clinical evidence and gender differences.

INTRODUCTION: Long term alcohol abuse is associated with deficiencies in essential nutrients and minerals that can cause a variety of medical consequences including accumulation of toxic metals. AIM: The aim of this research is to get evidence-based data to evaluate alcohol damage and to optimize treatment. Thiamine and thiamine diphosphate (T/TDP), zinc (Zn), selenium (Se), lead (Pb) and oxidative stress in terms of reactive oxygen metabolites (ROMs) were examined in blood samples from 58 alcohol dependent patients (17 females and 41 males). RESULTS: T/TDP concentration in alcoholics resulted significantly lower than controls (p < 0.005) for both sexes. Serum Zn and Se did not significantly differ from reference values. Levels of blood Pb in alcoholics resulted significantly higher (p < 0.0001) than Italian reference values and were higher in females than in males. ROMs concentration was significantly higher than healthy population only in female abusers (p = 0.005). CONCLUSION: Alcoholics show a significant increase in blood oxidative stress and Pb and decrease in thiamine. Impairment occurs mainly in female abusers confirming a gender specific vulnerability.

The network of the Italian laboratories: a proficiency test on the quantification of trace elements in serum.

A proficiency test on the quantification of Al, Cu, Mn, Se and Zn in serum was carried out to verify the performance of about 30 regional laboratories of the network of Italian laboratories. The exercise consisted of four runs in which the laboratories were free in choosing analytical methods to determine trace elements in freeze-dried animal serum. Laboratories performances were evaluated by the study of statistical functions as Coefficients of Variation (CV), Youden plot and Z-score value. As for Al, the results were generally characterized by good accuracy and precision, in spite of the low levels of the element (5-7 microg l(-1)). Copper determination had some problems only at low concentration (about 160 microg l(-1)--first run), in which an elevated number of anomalous data were found. Better data were achieved for Zn, for which anomalous values were mainly stragglers than outliers. Due to the low number of data for Mn (concentrations from 0.6 to 60 microg l(-1)) and Se (concentration from 45 to 106 microg l(-1)), a restricted statistical treatment was applied; for these elements high CV values were found (range from 30 to 80%). The results of this trial confirmed that participation in a proficiency test represents a benefit for all analytical laboratories. In fact, with few exceptions, most of the participants improved their performances in terms of Z-score values.