DEVICE FOR MEASURING SUBSTANCE CONCENTRATION IN A LIQUIDBODY,DEVICE FOR DETECTING SUBSTANCE CONCENTRATION IN ASAMPLE AND A DEVICE FOR DETECTING SUBSTANCES IN HUMAN OR ANIMAL BODIES AND A METHOD FOR DETECTING SUBSTANCES IN A LIQUID BODY

摘要

A device and method for detecting and measuring the concentration of a substance in a sample by optoacoustic spectroscopy in which light of selected discrete frequencies is directed onto the sample and the acoustic response of the sample is detected. The frequencies are selected according to the optoacoustic spectrum of the substance under test to distinguish that substance from others. A laser (6,74,54) is used as the light source and is controlled to emit the light in pulses and a piezoelectric device (7,56,76) is used to detect the acoustic response. Light of several frequencies may be used by using several lasers or a frequency tunable laser and emitting the pulses substantially simultaneously. The device and method are particularly suited for detecting the presence of substances in vivo, e.g. detecting glucose in the bloodstream, and avoids the need to puncture the skin and may be constructed so that it can be worn by the patient but they are also suited for in-vitro testing of substances in which case the device may be made personally portable for use on the desk-top or adapted to monitor a continuous process by continuously taking and testing samples from the main process line.