Ammonia detection can be done using gas sensors. Examples of different application areas of ammonia gas detection are; environmental monitoring, medical diagnostics, chemical laboratories and detection of ammonia in drinking water and wastewater (Timmer et al., 2005). High concentrations of ammonia are easy to detect while for very low concentrations different gas sensors operating with different sensing principles are required. Ammonia gas sensors operate at different temperatures, each with a specific range of detection limits and response times to quickly measure ppm and sub-ppm concentrations. Commercial ammonia sensors use several techniques for ammonia detection and can be classified as metal oxide sensors, conducting polymer detectors, catalytic ammonia sensors, and optical sensors. Ammonia gas sensors should be considered based on cost, maintenance, installation, and most importantly, which application-specific sensors are suitable. Metal oxide ammonia gas sensors are the most widely used and are usually made of tin sensors, for example SnO2 (Zakrzewska, 2001). These sensors are inexpensive and are based on the principle of conductance variation that occurs due to chemical adsorption of ammonia gas molecules on a sensitive layer. The selectivity and sensitivity of these sensors towards ammonia gas can be improved by using additives that will drive the adsorption of the gas molecules. By using additives such as Au and MoO3 ammonia sensors the detection limit of 1 ppm can be achieved. Metal oxide sensors have a detection limit of 1 to 1,000 ppm and operate at temperatures above 400°C. In applications such as environmental monitoring and combustion gas detection, these sensors are very useful. Sensors made of polymer......with paper core......ysis are needed. The use of non-selective detectors with gas samplers is also a good selective technique for accurately measuring ammonia. Table 1 (Timmer et al., 2005) summarizes all the parameters of the different types of sensors used for ammonia detection. In the methodological section, a scheme of experiments using sensors to detect ammonia in water will be presented. However, there are two methods described by the EPA for detecting ammonia in bodies of water. The first method (method 350.1) is the distillation method in which the sample is first buffered and then distilled in boric acid. The concentration of ammonia is directly proportional to the indophenol blue formed (SEMI, 1993). In the second EPA method (method 350.2) the sample is distilled in boric acid and the ammonia concentration is determined titrimetrically or colorimetrically (SEMI, 1993) .