Determination of mercury contents in facial whitening cream samples by direct thermal decomposition mercury analyzer

Abstract

Direct thermal decomposition mercury analysis is an efficient technique for determination of mercury in facial whitening creams. The analysis can be performed without any sample preparation. The samples can be weighed and placed directly into the analyzer. Thus, there is no chemical waste produced in sample preparation. The time and energy used in sample digestion are saved as well. The calibration curve between mercury absorbance in terms of peak height and weight of standard mercury in the range of 0.1-10 ng was created. The calibration curve was linear followed the equation y=2.003x10-2X– 5.14x10-4 with coefficient of determination (R2) 0.9991. The precision in term of repeatability were 14% and 5.9% rsd (n=3) at 1.2 and 868 µg kg-1, respectively. The recoveries were between 88-110%. The detection limit (LOD) was 0.1 µg kg-1 (3sd/m, n=10). The amount of mercury detected in 12 whitening cream samples sold in Chonburi province during the year 2019 were within the safety standard permitted in general cosmetics under the notification of the Ministry of Public, except two samples were over the permitted standard.