Limit of detection of 15N by gas-chromatography atomic emission detection. Optimization using an experimental design

Abstract This paper deals with the optimal conditions for the detection of 15N determined using a four-factor experimental design from [2 13C-1.3 15N] caffeine measured with an atomic emission detector (AED) coupled to gas chromatography (GC). Owing to the capability of a photodiodes array, AED can simultaneously detect several elements using their specific emission lines within a wavelength range of 50 nm. So, the emissions of 15N and 14N are simultaneously detected at 420.17 nm and 421.46 nm respectively. Four independent experimental factors were tested Helium flow rate (plasma gas) Methane pressure (reactant gas) Oxygen pressure Hydrogen pressure It has been shown that these four gases had a significant influence on the analytical response of 15N. The linearity of the detection was determined using 15N amounts ranging from 1.52 pg to 19 ng under the optimal conditions obtained from the experimental design. The limit of detection was studied using different methods. The limits of detection of 15N was 1...