Original scientific paper
DETERMINATION OF LOW ARSENIC CONCENTRATIONS IN LIGHT GASOLINE BY GFAAS TECHNIQUE
Mateja Djetelić Ibrahimpašić
orcid.org/0000-0003-4975-9360
; INA d.d. Rafinerija nafte Sisak
Anita Štrkalj
orcid.org/0000-0002-7117-4687
; University of Zagreb, Faculty of Metallurgy Sisak
Ana Vuković
; INA d.d. Rafinerija nafte Sisak
Ivan Boras
; INA d.d. Rafinerija nafte Sisak
Ana Škrobica
; INA d.d. Rafinerija nafte Sisak
Abstract
The main parts of the light naphtha isomerization unit in oil refinery are reactors loaded with platinum base catalyst. Even small amount of water, sulfur, oxygenates and/or nitrogen is poisonous for the catalyst. In addition, the catalyst activity is negatively affected by metals. Arsenic, one of the metal poisons, decreases the catalyst activity in μg/l quantity. Therefore, it’s crucial to detect it precisely in order to protect the expensive platinum based catalyst in time.
A procedure for determination of arsenic in light gasoline at μg/l levels by graphite furnace atomic absorption spectrometry (GFAAS) is proposed. GFAAS is good alternative for the determination of trace metals in petroleum fractions and distillates to relatively expensive ICP-MS. Sample stabilization was achieved by mixing appropriate volumes of the sample, propan-1-ol and nitric acid aqueous solution. This mixture resulted in one-phase medium (microemulsion), which was indefinitely stable. Pd(NO3)2 solution was used as modifier. Validation of the method includes microemulsion stability, linearity, yield, precision, limit of detection and limit of quantification.
Keywords
isomerization; platinum based catalyst; arsenic; gasoline; GFAAS; validation
Hrčak ID:
101246
URI
Publication date:
15.4.2013.
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