Precise determination of strontium isotope ratios by TIMS to authenticate tomato geographical origin.

Thermal Ionisation Mass Spectrometry (TIMS) was applied to discriminate a total of 118 tomato samples (berries, "passata", tinned tomatoes, sauce, double and triple concentrate) coming from two different countries. The TIMS technique gave significantly different results for the (87)Sr/(86)Sr ratios and δ‰ values between Chinese and Italian tomato samples, irrespective of the treatment type. This technique proved to be a "robust" method, suitable for a precise discrimination of the two geographical origins. TIMS was able, within the Italian samples, to discriminate different geographical production areas, by virtue of different (87)Sr/(86)Sr ratios and δ‰ values. This technique could be employed in the field of food safety and quality, as a profitable tool for authenticating tomato geographical origin.

Determination of rare earth elements in tomato plants by inductively coupled plasma mass spectrometry techniques.

In recent years identification of the geographical origin of food has grown more important as consumers have become interested in knowing the provenance of the food that they purchase and eat. Certification schemes and labels have thus been developed to protect consumers and genuine producers from the improper use of popular brand names or renowned geographical origins. As the tomato is one of the major components of what is considered to be the healthy Mediterranean diet, it is important to be able to determine the geographical origin of tomatoes and tomato-based products such as tomato sauce. The aim of this work is to develop an analytical method to determine rare earth elements (RRE) for the control of the geographic origin of tomatoes. The content of REE in tomato plant samples collected from an agricultural area in Piacenza, Italy, was determined, using four different digestion procedures with and without HF. Microwave dissolution with HNO3 + H2O2 proved to be the most suitable digestion procedure. Inductively coupled plasma quadrupole mass spectrometry (ICPQMS) and inductively coupled plasma sector field plasma mass spectrometry (ICPSFMS) instruments, both coupled with a desolvation system, were used to determine the REE in tomato plants in two different laboratories. A matched calibration curve method was used for the quantification of the analytes. The detection limits (MDLs) of the method ranged from 0.03 ng g(-1) for Ho, Tm, and Lu to 2 ng g(-1) for La and Ce. The precision, in terms of relative standard deviation on six replicates, was good, with values ranging, on average, from 6.0% for LREE (light rare earth elements) to 16.5% for HREE (heavy rare earth elements). These detection limits allowed the determination of the very low concentrations of REE present in tomato berries. For the concentrations of REE in tomato plants, the following trend was observed: roots > leaves > stems > berries.

Characterization of mercury species in soils by HPLC-ICP-MS and measurement of fraction removed by diffusive gradient in thin films.

The properties and behaviour of Hg depend on both the oxidation state and the chemical form: the bioavailability, toxicity, persistence and accumulation of mercury in the food web are strongly influenced by chemical speciation. The present work aims to determine the chemical forms of mercury present in soil and to evaluate the fraction of mercury in soil solution available to plants. In order to do this, we analyzed eight samples of contaminated soils with Hg concentrations ranging from 1.31 to 21.7 mg kg(-1), collected from different depths (0-10 and 40-50 cm) close to an abandoned industrial site in Val Basento (southern Italy). Two innovative analytical techniques were used: HPLC-ICP-MS and diffusive gradient in thin films (DGT). The analytical procedure was validated using ERM 580-certified sediment and spiked samples in the case of HPLC-ICP-MS, and by a performance test in the case of DGT. In all samples, the only species found in soil and soil solution was MeHg(+) and Hg(2+). In soil, the MeHg(+)/Hg(tot) ratio ranged from 0.05% to 0.82%; total mercury in soil solution was less than 0.01% of total mercury in soil. The percentage of MeHg(+) in soil solution varied considerably (from 0% to 50%), with a maximum concentration of 0.02 mg L(-1). The root available concentration evaluated by DGT is comparable to the total mercury content of the soil solution measured by HPLC-ICP-MS. The DGT results suggest that all mercury in solution is available for uptake in DGT, and that mercury is supplied from soil to solution. However, for all samples the soluble and root available (DGT-labile) fractions of mercury are generally very low with respect to the total mercury concentration. This study confirmed that both HPLC-ICP-MS and DGT techniques are suitable tools for the estimation of Hg root availability and in assessing the risk from contaminated soils.

Radionuclides in fruit systems: a review of experimental studies.

Existing information on processes and parameters analysed in experimental studies on fruits was reviewed at the inception of the activities of the IAEA BIOMASS Fruits Working Group. Additional information on experimental studies, collected during the activities of the Group and not included in the Review, is presented and discussed in this paper. Studies on deposition of (14)CO2, CO(35)S and (3)H2O in the gas phase to apple, raspberry, strawberry and blackcurrant have filled gaps in knowledge of uptake of gaseous pollutants in fruit plants, quantifying processes of deposition, translocation and carry-over between seasons. Measurements over a period of six years on vine plants contaminated via leaves and soil by dry deposition of 137Cs and 90Sr have improved knowledge of the processes of direct deposition to fruit, translocation and carry-over of radionuclides from year to year. Additional information is given on soil to fruit transfer of U, Th and Pb for apple and mandarin grown under intensive agricultural conditions.