A robust set up has been developed that permits determination of microcarbon residue (MCR) with high accuracy and precision, in as many as twenty six petroleum materials at a time. The effect of gas flow rate and sample vial size in our set up is presented. The general belief that small amounts of oxygen during initial stages of coking increases MCR is investigated, since sample reaction toward CO2 production is expected at priori. In our study FTIR spectra of samples before and after heating indicates that presence of small amounts of air may or may not increase MCR, depending upon the chemical nature of the sample. This is in contrast to the general assumption that presence of small amounts of air tends to increase MCR residue. Heavy oils and fractions samples analyzed by the developed set up matched literature reported values. Preliminary findings suggest that (nC7) asphaltenes are important contributors to MCR.