Ammonia Nitrogen program for calculation in known addition. N001 LBL N N002 SF 10 N003 CALCULATION OF N004 PSE N005 AMMONIA N006 PSE N007 NITROGEN N008 PSE N009 ENTER THE SLOPE (MV) N010 PSE N011 CF 10 N012 INPUT S N013 SF 10 N014 ENTER P N015 PSE N016 CF 10 N017 INPUT P N018 SF 10 N019 ENTER R N020 PSE N021 CF 10 N022 INPUT R N023 SF 10 N019 ENTER DELTA E (MV) N020 PSE N021 CF 10 N022 INPUT E N023 (P*R)/(((1+P)*(10^(E/S)))-1) N024 STO Q N025 VIEW Q N026 RTN CALCULATIONS: The slope S of the ammonia electrode is found by subtracting E1 from E2 and taking its absolute value. eq 1 S = | E1 - E2 | delta E is found by subtracting E3 from E4. eq 2 delta E = E3 - E4 Using the slope of the electrode S, delta E and equation 3 the concentration ratio Q is found. eq 3 Q = (p*R) / {((1+p)x10^(delta E /S)) - 1} Where: Q = Concentration ratio S = |slope of the electrode| or |E1 - E2| p = Volume of standard / Volume of sample and ISA r = Volume of sample and ISA / Volume of Sample Multiplying Q by the concentration of the added standard, the concentration of the original sample is found using equation 4. eq 4 C' = Q x Cs Where: C' = Total sample concentration, mg/l as NH3 - N Q = is from equation 3 Cs = Concentration of the added standard, 1000 mg/l as Nitrogen