Development of a Paste‐type Certified Reference Material of Tomato for Elemental Analysis: Certification and Long‐term Stability Study

Abstract

A paste‐type certified reference material (CRM) of tomato was developed for accurate elemental analysis of canned foods. Accurate mass fractions of cadmium (Cd), lead (Pb), and tin (Sn) in the tomato paste CRM were determined by isotope dilution inductively coupled plasma mass spectrometry. The certified values and their expanded uncertainties (k=2 at approximately 95% level of confidence) for Cd, Pb, and Sn were (0.297 ± 0.015) mg/kg, (0.213 ± 0.010) mg/kg, and (221.2 ± 9.5) mg/kg, respectively. Homogeneity of the CRM was 0.3%, 1.8%, and 0.2% for Cd, Pb, and Sn, respectively, which were estimated using the relative standard deviation of the measurement results of 10 separate sample bottles from one batch of the CRM. Major contributions to the measurement uncertainties for Cd and Sn were the uncertainties of the isotope ratios of Cd and Sn in the sample and the elemental standards. The uncertainty for Pb was mainly affected by sample homogeneity. Stability tests were conducted for 6 and 12 months at −20, 4, and 25°C, and the storage temperature for the CRM was determined to be −20°C. To investigate long‐term storage, the mass fractions of Cd, Pd, and Sn in the CRM were re‐determined after storage for 7 years. The results were in good agreement with the certified results implying that this CRM is stable for 7 years if kept at an appropriate storage condition with vacuum packaging the amber glass bottles in aluminum‐coated polymer bag.

Uncertainty evaluation in reference material characterization by double isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-MS)

“…The processing procedure for this CRM was described previously [29]. The sample preparation and instrument operation procedures at KRISS for double ID-ICP-MS were described previously [29][30][31], and are based on those reported by Watters et al [32]. However, because details on the measurement procedure are vital for uncertainty evaluation, and because some differences exist between the procedures in this study and those described previously, the experimental procedures used are necessarily described in detail.…”

Traceable quantitative analysis of Ag x Cu1−x alloy films by ID ICP-MS, RBS and MEIS

“…The relative mole fractions of Ag and Cu in the five Ag x Cu 1−x alloy films with different composition were measured by selectively dissolving the alloy layers from the Si substrate and determining the amount of the constituent elements using a double ID ICP-MS. The principle and detailed procedure of the double ID ICP-MS were described previously [9,10,[15][16][17][18][19].…”

Study on production and utilization of a reference material for determination of multi-residue pesticides in tomato matrix

“…Previously, some publications have researched on production of CRM or RM for pesticides in food matrix such as carrot/potato matrix [15], apple [16], cabbage [17], tea [13], olive oil [18], passion-ower fruits [19], grapes [20], cucumber [21], tomato [22,23]. Storage condition especially temperature is highly affect shelf life the RM.…”