Low density polyethylene window for the determination of mercury by cold vapor atomic absorption spectrometry

摘要

In this study the reliability of a low density polyethylene (LDPE) window with thickness of 65 μm attached to both ends of a glass cell was evaluated for the determination of mercury by cold vapor atomic absorption spectrometry (CVAAS). In the cold vapor system quartz window was replaced by this LDPE window. The results obtained using different standards and real samples were in good agreement with those obtained by quartz window. The obtained calibration curve was linear in the range 2.5-25 ng mL~(-1) with the equation of Y = 0.021x (R~2 = 0.998) at 253.7 nm. The relative standard deviations for within days and between days analysis were in the range of 0.40-3.37 and 0.95-3.27 per cent, respectively. In order to evaluate the reliability of the window, three fish samples were analyzed by cold vapor atomic absorption system using cells with both quartz and LDPE windows. The results obtained by LDPE were in good agreement with their quartz counterparts. The mean number of measurements of a certain LDPE window depends on the concentration of mercury in the solution. The window must be replaced after 48 repeated measurements for a mercury solution of 150 ng mL~(-1).