Determination of sulfur in bovine serum albumin and l-cysteine using high-resolution continuum source molecular absorption spectrometry of the CS molecule

•The content of S was determined in bovine serum albumin and l-cysteine using HR-CSMAS.•Bovine serum albumin and l-cysteine were digested using a microwave lab station to obtain sulfate.•Sulfur was determined in two protein dietary supplements.

In this study, the content of sulfur in bovine serum albumin and l-cysteine was determined using high-resolution continuum source molecular absorption spectrometry of the CS molecule, generated in a reducing air-acetylene flame. Flame conditions (height above the burner, measurement time) were optimized using a 3.0% (v/v) sulfuric acid solution. A microwave lab station (Ethos Plus MW) was used for the digestion of both compounds. During the digestion step, sulfur was converted to sulfate previous to the determination. Good repeatability (4–10%) and analytical recovery (91–106%) was obtained.