文档介绍：Chapter 12
Chemical sensors for mercury vapour
Vladimir M. Mirsky and Majlinda Vasjari
INTRODUCTION
Mercury is a toxic substance that, through human and natural activ-
ities, cycles through the atmosphere, hydrosphere, and ecosphere
affecting the health of both humans and wildlife. It enters the envi-
ronment naturally through erosion, fire, and volcanic processes, as well
as a result of human industrial practices. The human activities such as
combustion, smelting, and mining have elevated global mercury levels
to approximately three times those found before industrialization. Once
released, mercury persists in the environment where it circulates be-
tween air, water, sediments, and biota in various forms. Mercury is
present everywhere in the environment. The level of Hg in air varies
from ng/m3 to 10 mg/m3.
Mercury may be present in air in different chemical states such as
the elemental form (as a vapour or adsorbed on particular matter) or in
the form of volatile pounds (mercury chloride, methyl-
mercuric chloride, and dimethyl mercury). Although elemental mer-
cury is only one of the mercury forms which is not as toxic as anic
or ionic forms, analytical determination of elemental mercury is of
special importance. Such analysis is used not only for determination of
elemental mercury in environment, but also as a method for determi-
nation of other forms of mercury after reductive treatment.
A number of analytical methods were developed for determination of
elemental mercury. The methods are reviewed in Refs. [1–4]. They in-
clude traditional analytical techniques, such as atomic adsorption spec-
troscopy (AAS), atomic fluorescence spectroscopy (AFS), and atomic
emission spectroscopy (AES). The AAS is based on measurements of
optical adsorption at or nm. Typical value of the detection
limit without pre-concentration step is over 1 mg/l. The AEF is much
more sensitive and allows one to detect less than ng/l of