palintest Macro 900 Operation Manual

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palintest Macro 900 Operation Manual Manual pdf 94 page image

Macro 900 Operation Manual V3© 2013 Palintest Ltd. www.palintest.com Page 94 of 14716.4. PT 1541 Ammonium/Ammonia ElectrodeAmmonium (NH 4 ) and Ammonia (NH 3 ) can be measured by the MAP 2000/2100using the optional PT 1541 Ammonium/Ammonia electrode within pH 5 – 8range.The Ammonium ISE electrode will suffer interference from Potassium, Sodiumand Magnesium ions, which are similar in nature.16.4.1. Ammonium Calibration Solution PreparationWhen an Ammonium ISE electrode is first installed, it must be calibrated atthree points. In order to achieve this, three batches of Ammonium calibrationsolution must be prepared.The solutions required are two 200mL batches of Ammonium (as NH 4 ) at aconcentration of 10ppm and one 250mL batch of Ammonium (as NH 4 ) at aconcentration of 100ppm.The three calibration solutions should be freshly prepared by serial dilution from1000ppm calibration standard. The following Ammonium standard isrecommended:Part number: SS-702-1610Description: 500mL Ammonium 1000ppm as NH4 ISESupplier: T E Laboratories Ltd, Ireland.Contact: http://www.tellab.ieBe sure to handle chemicals with care and to read and comply with allhealth and safety advice.Preparing the 100ppm solution250mL of 100ppm solution is required. To prepare this, mix 25mL of 1000ppmcalibration standard with 225mL of deionised water.Dispense 200mL of the 100ppm solution into a calibration bottle and retain50mL for preparation of the 10ppm solution.Preparing the 10ppm solutionA total of 400mL of 10ppm solution is required. To prepare this, mix 40mL ofthe 100ppm solution you have just prepared with 360mL of deionised water.Dispense the 10ppm solution into two calibration bottles (200mL each).Achieving the correct temperatureDuring three point calibration, the 100ppm solution and one batch of the10ppm solution must be at exactly the same temperature. The second batch of10ppm solution must be at least 10ºC cooler.In order to achieve this, one batch of the 10ppm solution should be put into arefrigerator and the other two solutions should be put into a water bath at25ºC.Once all three solutions are at a stable temperature, calibration can begin.