A 100 mg L1 iridium solution was p

A 100 mg L1 iridium solution was prepared from the 1000
mg L1 stock solution (Fluka Chemical). Iridium modifier was
co-injected into graphite furnace with each aliquot of sample.
The solution inside the autosampler reservoir was 0.2% (v/v)
HNO3. Fuel ethanol samples were purchased at the local gas station
in Araraquara City São Paulo State, Brazil, and analyzed without
previous treatment. All solutions were stored in Nalgene™ highdensity
polypropylene flasks (Nalge Nunc International, Rochester,
NY, USA). Plastic bottles, autosampler cups and glassware materials
were cleaned by soaking them overnight in a 10% (v/v) HNO3
solution and rinsing abundantly in de-ionized water before use.