1. Introduction
Palladium spreads through the atmosphere mainly by catalytic
converters of cars which are used to reduce the concentration of CO,
NOx and HC in exhaust fumes [1–7]. Therefore, the concentration of
Pd together with other platinum group elements (PGEs) is expected
to increase in the environment in proportion to the number of cars
fitted with catalytic converters.
Determination of Pd in several matrices including urban airborne
particulate matter by electrothermal atomic absorption spectrometry
(ETAAS) is not an easy task because Pd concentration may mostly be
below its limit of detection (LOD) and pre-concentration procedure is
needed prior to the analysis [8]. However, the pre-concentration procedure
is time consuming, moreover there are more potential errors
due to the blank values, analyte losses and contamination. Since the
concentration levels of Pd in urban airborne particulate matter are
close to the blank values, even small alterations in blanks lead to
considerable deviations. In addition, since Pd is a refractory element,
a relatively high atomization temperature and fast atomization rate
should be applied. In this case, the application of background correction
methods by deuterium or Zeeman system is problematic due to
fast changes of background intensities caused by ultrafast heating
rate. When solid sampling is applied, the mass of sample introduced
into the graphite furnace is generally higher than those after digestion;
therefore, a powerful background correction is necessary.
On the other hand, solid sampling electrothermal atomic
absorption spectrometry (SS-ETAAS) has many well-known advantages
compared to digestion techniques, namely (i) less waste
of time and reagent, (ii) no risk of contamination and no loss of
analyte during sample preparation, (iii) lower sample demand
(b1 mg) providing the determination of the analyte distribution
in micro-scale, and (iv) generally no need for analyte enrichment
because the sample and the analyte is not diluted [9]. Sometimes,
one of the atomic absorption lines of concomitant elements or
hyperfine rotational absorption lines of a molecule formed in the
gas phase may exactly overlap with the analytical line of the investigated
element. This phenomenon cannot be eliminated even with
the traditional background correction systems. However, the high
resolution-continuum source electrothermal atomic absorption
spectrophotometer (HR-CS ETAAS) with ultra high resolution
power at pm level and, a precise and simultaneous background correction
system is capable to eliminate all of the above-mentioned
interferences appropriately [10].