Optical emission spectrometer (OES) can be used to analyze the composition of all the elements at the same time. It can also be used for real time analysis. However, for reliable analysis, it is necessary to have standard reference materials with a closer composition.
ICP-OES analysis will be useful to determine the concentration of trace elements (Ti, Pb, Al and Ca) in alloy steels with better accuracy.
For S convert it as SO2 or precipitating it as BaSO4. The following links will be some help for the analysis of sulphur