34 35• Reinsert the cuvette into the instrument.• Press TIMER and the display will show the countdown priorto the measurement or, alternatively, wait for 6 minutesand press READ. When the timer ends the meter will performthe reading. The instrument displays concentration in mg/Lof nitrite.• Press the V or W to access the second level of functions.• Press the Chem Frm functional key to convert the result in mg/L of nitrogen-nitrite (NO2–-N) and sodiumnitrite (NaNO2).• Press the V or W to go back to the measurement screen.INTERFERENCESInterference may be caused by the following ions:ferrous, ferric, cupric, mercurous, silver, antimonious, bismuth, auric, lead, metavanadate and chloroplatinate.Strongly reducing and oxidizing reagents.High levels of nitrate (above 100 mg/L) could yield falsely high readings due to a minute amount ofreduction to nitrite that could occur at these levels.Nitrite LRSPECIFICATIONSRange 0.00 to 0.35 mg/LResolution 0.01 mg/LAccuracy ±0.02 mg/L ±4% of readingTypical EMC ±0.01 mg/LDeviationLight Source Tungsten lamp with narrow band interference filter @ 525 nmMethod Adaptation of theEPA Diazotization method 354.1. The reaction between nitrite andthe reagent causes a pink tint in the sample.REQUIRED REAGENTSCode Description QuantityHI 93707-0 Powder reagent 1 packetREAGENT SETSHI 93707-01 Reagents for 100 testsHI 93707-03 Reagents for 300 testsFor other accessories see page 46.MEASUREMENT PROCEDURE• Select theNitrite LR method using the procedure describedin theMethod Selection section (see page 11).• Fill the cuvette up to the mark with 10 mL of unreactedsample (up to the mark) and replace the cap.• Place the cuvette into the holder and close the lid.• Press ZERO key. The display will show “-0.0-” when themeter is zeroed and ready for measurement.• Remove the cuvette.• Add the content of one packet of HI 93707-0 reagent.Replace the cap and shake gently for about 15 seconds.Nitrite LRNITRITE LOW RANGE10 mL