Chemical sensors for mercury vapour
- A number of analytical methods were developed for determination of elemental mercury. They include traditional analytical techniques, such as atomic adsorption spectroscopy (AAS), atomic fluorescence spectroscopy (AFS), and atomic emission spectroscopy (AES). Other analytical methods include neutron-activation analysis and laser photo-acoustic spectroscopy (detection limit about 5 μg/l). To increase sensitivity and selectivity of these methods, a preconcentration of mercury is widely performed. This can be realized by exploring high affinity of mercury to gold. Mercury and its volatile compounds can easily be adsorbed on gold at normal temperatures and can be released quantitatively upon heating. Hence, gold has been used as an adsorbent for the accumulation of mercury to a concentration sufficient for further spectroscopic analyses. The main disadvantage of mercury sensors based on bare gold layers is their poor selectivity and applications of such sensors for real probes and makes necessary a pre-treatment of probes. Mercury sensorsA number of analytical methods were developed for determination of elemental mercury. They include traditional analytical techniques, such as atomic adsorption spectroscopy (AAS), atomic fluorescence spectroscopy (AFS), and atomic emission spectroscopy (AES). Other analytical methods include neutron-activation analysis and laser photo-acoustic spectroscopy (detection limit about 5 μg/l). To increase sensitivity and selectivity of these methods, a preconcentration of mercury is widely performed. This can be realized by exploring high affinity of mercury to gold. Mercury and its volatile compounds can easily be adsorbed on gold at normal temperatures and can be released quantitatively upon heating. Hence, gold has been used as an adsorbent for the accumulation of mercury to a concentration sufficient for further spectroscopic analyses. The main disadvantage of mercury sensors based on bare gold layers is their poor selectivity and applications of such sensors for real probes and makes necessary a pre-treatment of probes. Mercury sensors based on thin gold layers require regular calibrations. In ideal cases, the calibration should be performed before each measurement. Therefore, a calibration technique should be compatible with design and concept of the mercury vapor sensor.…