Macro 900 Operation Manual V3© 2013 Palintest Ltd. www.palintest.com Page 99 of 14716.5. PT 1542 Nitrate ElectrodeNitrate (NO3) can be measured by the MAP 2000/2100 using the optional PT1542 Nitrate electrode within a pH range of 3 – 10.The Nitrate ISE electrode will suffer interference from Chloride, Bromide,Fluoride, Sulphate, Chlorate and Perchlorate ions, which are similar in nature.16.5.1. Nitrate Calibration Solution PreparationWhen a Nitrate ISE electrode is first installed, it must be calibrated at threepoints. In order to achieve this, three batches of Nitrate calibration solutionmust be prepared.The solutions required are two 200mL batches of Nitrate at a concentration of10ppm and one 250mL batch of Nitrate at a concentration of 100ppm.The three calibration solutions should be freshly prepared by serial dilution from1000ppm calibration standard. The following Nitrate standard is recommended:Part number: SS-712-1610Description: 500mL Nitrate 1000ppm 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.