Validation and optimization of an analytical method based on cold vapor atomic absorption spectrometry for the determination of mercury in maternal blood, cord blood, and placenta samples

Abstract

In this study, a simple and sensitive cold vapor atomic absorption spectrometry (CVAAS) method was developed and validated for the determination of mercury in maternal blood, cord blood, and placenta samples. Biological samples were obtained from 113 mother-newborn pairs. Infant characteristics such as birth weight, birth length, and head circumference were recorded. Microwave-assisted acid digestion was applied and a cold vapor module was utilized for atomization. The method showed linearity in the range of 0-20 μg/L with a detection and quantification limit equal to 0.23 μg/L and 0.76 μg/L, respectively, as well as very good repeatability not exceeding 3%- The calibration curve was characterized by a high correlation coefficient (r2=0.9992). Validation was performed in terms of precision and accuracy with the use of certified reference materials (CRM). The method was applied to the analysis of spiked CRM samples yielding satisfactory results (97.4-101.2%). The mean mercury levels of maternal blood, placentas, and cord blood were 3.23±1.46 μg/L, 12.24±11.50 μg/kg, 3.69±3.44 μg/L, respectively. As a result of the statistical analysis, a significant correlation was found between placenta-Hg and cord blood-Hg levels (r=+0.231, p=0.014). In addition, birth head circumference and cord blood-Hg levels were found to be correlated to each other (r=+0.318, p=0.033).