Sulfur fractionation using high-resolution continuum source molecular absorption spectrometry with calcium and hydrophobic palladium nanoparticles as chemical modifiers.

The unprecedented use of high-resolution continuum source molecular absorption spectrometry (HR-CS MAS) for the fractionation of organic and inorganic sulfur (S) species through monitoring the CS molecule is presented here. Two separate methods for determining organic (CS) and inorganic (CS) sulfur were developed to work sequentially. The optimized temperature program for both methodologies has two pyrolysis steps and one vaporization step (1st T: 1800 and 2T: 800 °C, and T: 2500 °C). The fractionation was achieved by implementing hydrophobic Pd NPs and Ca as chemical modifiers for the CS and CS methods. Method development was performed by applying different statistical models, allowing the definition of optimal conditions for the chemical modifier mass, and minimizing the S species interconversion, i.e., Doehlert design, and central composite design. The limits of detection (LoD) for CS and CS were 2.4 and 2.1 mg L, respectively. Recovery tests evaluated the method's specificity and accuracy; over 92 % recovery was found for both CS and CS. Thus, the proposed methods offer a reliable alternative for fractionating organic and inorganic S by using HR-CS MAS.