Determination of triacetin content in filter rods has always been an area of detection and measurement that has lagged behind the other areas of measurement in the manufacture of filter rods. The application of triacetin to the processed acetate tow continues to be a critical point in the process, the measurement of which relies on manual weighing (wet & dry) of filter rods or remote laboratory processing. Both methods have high costs either in wasted materials or in laboratory time and materials. At the CORESTA meeting 2003 in Freiburg this issue was addressed with a presentation that demonstrated a mathematical correlation between the amount of triacetin and the total mass of the filter rod, versus the microwave values A and B for the same filter rod. But this correlation failed due to a number of reasons. In 2008 we will show the culmination of this combined technology with an improvement in the level of correlation achieved by integrating pressure drop and diameter of the filter rod to the algorithm. The study data is provided from the combination of a standard quality parameter testing station for filter rods with a microwave resonator tuned to the triacetin resonance frequency. The study was completed using 10 very different filter tow items. For each tow item, filter rods at 3 different operation points (PD levels) were produced and each operation point was applied with 5 different levels of triacetin in steps of ~20 mg. The results of these tests are displayed and discussed in this poster presentation. The data also shows that the greatest level of accuracy can be achieved with a calibration for a specific filter tow type, but even with a universal calibration, accuracy of this measurement technique challenges those achieved by the other methods. This means that an at-line virtually instant measurement of triacetin is possible today, and dependent on the levels of accuracy required, instrument configurations can be tailored to the specific application.