Determination of mercury in alcohol vinegar samples from Salvador, Bahia, Brazil

- This is the second work that reports the determination of mercury in vinegar.
- A direct method for the determination of mercury in vinegar is proposed.
- The proposed sample preparation included determination using external calibration.
- Data on the mercury content of Brazilian vinegars are reported.
- Optimization of the method enabled sensitive analysis.

This paper proposes a direct method for the determination of mercury in vinegar using ultrasound extraction and cold vapor atomic absorption spectrometry (CV AAS). The optimization step was performed using chemometric techniques, a full factorial design and a Box-Behnken matrix, where the factors studied were sodium tetrahydroborate flow rate, isoamyl alcohol volume, thiourea concentration and sonication time.Using the optimized conditions, the method allowed the determination of mercury using external calibration, with limits of detection and quantification of 14 and 47 ng L−1, respectively, and precision expressed as relative standard deviation of 3.87 and 8.11% for vinegar samples with mercury contents of 759.4 and 318.5 ng L−1, respectively. There is no certified reference material of vinegar for evaluation of the accuracy; however, spike/recovery tests were performed in eleven samples. The recovery values ranged from 85 to 119%.The method was used to determine the mercury content of eighteen alcohol vinegar samples acquired in Salvador City, Bahia, Brazil. The mercury content of these samples ranged from 51.9 to 759.4 ng L−1.