Oxford RF Sensors Ltd., Weston on the Green, U.K., offers a handheld fuel analyzer that provides real-time, in-field measurements of diesel/biodiesel mixtures with the same accuracy as laboratory sampling methods. Using patented RF technology developed in conjunction with the University of Oxford, the device measures the amount of biodiesel in diesel and will also indicate whether the sample contains FAME or unrefined vegetable oil, contamination of the fuel, or if a nondiesel sample is being tested. When dipped in the sample, the device takes a reading in 20 s and displays the blend percentage. Accuracy is to within ±1% over the 0%–100% range of biodiesel concentrations, comparable to standard FTIR spectroscopy measurements and correlating well with standard reference methods.