The InfraCal 2 Biofuel Analyzer is a low-cost, single wavelength analyzer with filters preset for a particular measurement – either biodiesel in diesel or ethanol in gasoline. Biodiesel has a characteristic infrared absorption band at 5.73 μm (1745 cm-1). Ethanol’s infrared absorbance is at 9.6 μm (1045 cm-1). As the biodiesel or ethanol percentage increases, the infrared absorbance increases. An internal calibration table in the InfraCal 2 Biofuel Analyzer converts infrared absorbance to a digital readout in percent. A fuel sample is placed directly on the exposed ATR sample window and after 10 seconds the percent biodiesel or percent ethanol is displayed.