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Title: Evaluation of AN analytical sensors ammonium probe for the grant\YSI 3800
Author: National Rivers Authority
Document Type: Monograph
This report describes the results of tests carried out on an Analytical Sensors ammonium ISE (ion selective electrode), picked at random from a batch delivered to Thames Region and fitted into a Grant\YSI 3800 water quality monitor. The results show that the sensor is significantly more reliable than the one which it replaces and that field staff have increasing confidence in the readings produced by it. It is affected by water flow (3%) and also responds to potassium (8%) and sodium (0.1%), as do all ammonium ISE's. The accuracy in laboratory calibration standard solutions is -3% bias with 0.3% precision, however the accuracy in normal field use will be between 10% and 15% due to other factors (interference, drift, etc). The limit of detection was found to be less than 0.01 mg/1, but the presence of potassium and other interferences in the field needs to be considered as a 0.1 mg/1 change in the potassium level would change the instrument reading by approximately 0.01 mg/1. The lifetime of the probe tested is greater than 10 months, and the estimated minimum lifetime of probes used in the field is approximately 4 months.
Publisher: National Rivers Authority
Publication Date: 1995
Publication Place: Bristol
Subject Keywords: SensorsEvaluationAmmoniumPotassiumPerformance testing
Extent: 31
Total file downloads: 269

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