Optical Oxygen Sensors

Oxygen is an immensely important chemical species — essential for life. The need to determine levels of oxygen occurs in many diverse fields. In environmental analysis, oxygen measurement provides an indispensable guide to the overall condition of the ecology and it is routine practice to monitor oxygen levels continuously in the atmosphere and in water. In medicine, the oxygen levels in the expired air or in the blood of a patient are key physiological parameters for judging general health. Such parameters should ideally be monitored continuously, which may present problems. Determining oxygen levels in blood requires blood samples which may be difficult to take or impossible to take regularly — the elderly suffer from collapsed veins, while babies may only have 125 cm³ of blood. The measurement of oxygen levels is also essential in industries which utilise metabolising organisms: yeast for brewing and bread making, and the plants and microbes that are used in modern biotechnology, such as those producing antibiotics and anticancer drugs. Here, the background to oxygen measurements is described and work to develop new optical oxygen sensors which utilise the luminescence of platinum metals complexes is discussed.