Pulse oximetry is one of the most commonly employed monitoring modalities in critical care setting. Conventional pulse oximeters use two leds at different wavelengths and a photodiode to estimate blood oxygen saturation noninvasively, based in the difference of absorption coefficients between hemoglobin and deoxyhemoglobin. Nevertheless, factors such as low oxygen saturations, skin melanin content, nail polish presence or led wavelength displacement, modify differently the expected light absorbance for both LEDs. To address these issues, a novel approach combining a single led and a Buried Quad Junction photodetector is proposed. With this fundamental modification of the pulse oximetry principle, errors associated with the aforementioned modifying effects are expected to be reduced. The preliminary results show that there is a correlation of 0.84, -0.93, 0.91 and -0.88 for channels 1, 2, 3 and 4 respectively between our proposed method and the response from the measuring reference.