New Ultrasound-Assisted Extraction Sample Preparation Procedure for the Fast Determination of Total Sn in Canned Tomatoes by HG-ICP OES.

An analytical method with no need for laborious sample preparation before determining the total Sn in canned tomatoes by hydride generation (HG) coupled to inductively coupled plasma optical emission spectrometry (ICP OES) was developed. The ultrasound-assisted extraction with various reagents (acidic media: HCl, HNO₃, CH₃COOH or aqua regia and alkaline: TMAH) that could replace the traditional wet sample digestion in the presence of a concentrated HNO₃-H₂O₂ mixture was tested and compared. Tin hydride was generated directly from the prepared sample solution in the reaction with 1% NaBH₄ or via prior acidification with a 1 mol L⁻¹ HCl. The effect of the sample pretreatment before HG-ICP OES measurements on the Sn signal was also examined. The best results were obtained with aqua regia as the extraction medium, followed by a simple two-fold dilution of the sample extract combined with the addition of L-cysteine. The developed method was characterized by a detection limit of Sn at 0.74 ng g⁻¹, a precision of better than 6%, and a trueness, verified by the analyte spike-and-recovery test, of 98.4–104%. Its usefulness was demonstrated by the determination of Sn in seven canned tomatoes. [ABSTRACT FROM AUTHOR]