User manual HANNA INSTRUMENTS HI 38074

[. . . ] Instruction Manual SPECIFICATIONS Range 0 to 5 mg/L (ppm) as Boron Smallest Increment 0. 2 ppm Boron Analysis Method Titration Sample Size 50 mL Number of Tests 100 Case Dimensions 235x175x115 mm (9. 2x6. 9x4. 5") Shipping Weight 780 g (27. 5 oz. ) · Fill the plastic vessel with 50 mL of sample (up to the mark). 50 mL · Add 1 packet of Mannitol reagent and swirl gently to dissolve. HI 38074 Boron Test Kit for Irrigation Water · Add 3 drops of HI 38074A-0 Boron Reagent and swirl to mix. · Measure the pH: - If pH is lower than pHstart (e. g. : pH=7. 52), use the other plastic pipette to add HI 38074E-0 Boron Reagent drop by drop, swirling after each drop, while keeping an accurate count of the number of drops being added to the solution. Keep adding the reagent until pH becomes equal or higher than pHstart (7. 85). [. . . ] It may be present naturally in water or may find its way into a watercourse through industrial waste effluents. Boron in excess of 2. 0 mg/L in irrigation water is detrimental to many plants, but some plants may even be affected adversely by concentrations lower than 1. 0 mg/L. The US Department of Agriculture reports the following classification: ppm of Boron effect on crops <0. 5 good (except for very sensitive crops) 0. 5-2. 0 some risks (many crops must be excluded) >2. 0 dangerous (may only be used for very tolerant crops) Note: mg/L is equivalent to ppm (parts per million). · Insert the Checker pH electrode into the vessel and measure the pH. If pH is higher than 7, add HI 38074B-0 reagent drop by drop, swirling after each drop, until pH becomes lower than 7. · Using one of the plastic pipettes, add drops of HI 38074C-0 Boron Reagent, swirling after each drop. - If pH does not change after addition of the powder packet, boron is absent. As a confirmation, add one drop of HI 38074E-0 reagent and pH will immediately increase a lot. BORON CONVERSION TABLE number of drops 1 2 3 4 5 6 7 8 9 10 11 12 13 mg/L Boron 0. 2 0. 4 0. 6 0. 8 1. 0 1. 2 1. 4 1. 6 1. 8 2. 0 2. 2 2. 4 2. 6 number of drops 14 15 16 17 18 19 20 21 22 23 24 25 26 mg/L Boron 2. 8 3. 0 3. 2 3. 4 3. 6 3. 8 4. 0 4. 2 4. 4 4. 6 4. 8 5. 0 5. 2 CHEMICAL REACTION The Hanna Test Kit allows the determination of boron concentration in irrigation waters by direct titration of boric acid. · Keep on adding HI 38074C-0 reagent until the pH reaches the 7. 8±0. 2 value. Write down the exact pH value and report it as pHstart (e. g. : pHstart=7. 85). Note 1: If pH stabilizes at a value higher than 8, too many drops of HI 38074C-0 reagent have been added. In this case, add 1 drop of HI 38074B-0 reagent and swirl, then add again drops of HI 38074C-0 to adjust the pH to 7. 8±0. 2. Note 2: If carbonates are present, the pH readings will show a drift after each addition. Wait until the pH stabilizes before adding the next drop of HI 38074C-0 reagent. PRINTED IN ITALY INSTRUCTIONS READ THE ENTIRE INSTRUCTIONS BEFORE USING THE KIT · Calibrate the pH electrode following the instructions in the Checker instrument manual. 10/00 Interferences · Compounds with buffering capacity (substances that keep the pH of sample at a constant value, e. g. phosphate buffer, ammonia buffer): if after Mannitol reagent has been added pH of sample does not change, verify if pH increases a little (0. 05 pH units) by adding HI 38074E-0 reagent drop by drop. In this case boron may be present, but a buffer interferes with boron determination. It is possible to have only an indication for boron concentration. [. . . ] Pour the sample into the plastic vessel and perform the test as described above. REFERENCES P. Sequi, Chimica del suolo, Patron editore, Ed. 1991 HEALTH AND SAFETY The chemicals contained in this kit may be hazardous if improperly handled. Read the relevant Health and Safety Data Sheet before performing this test. [. . . ]