PL 100 / PL 101 Amperometric Chlorine Titrators Instruction Manual
Dear Customer, Thank you for choosing a Hanna Product. This instruction manual has been written for the following products: PL 100 Free Chlorine Titrator PL 101 Total Chlorine Titrator Both the instruments have features such as recorder outputs, 12VDC power supply for safety and reduction of EMI and built-in stirrer. Please read this instruction manual carefully before using the instrument.
TABLE OF CONTENTS PRELIMINARY EXAMINATION . . . . . . . . . . . . . . 4 GENERAL DESCRIPTION . . . . . . . . . . . . . . . . . 5 FUNCTIONAL DESCRIPTION . . . . . . . . . . . . . . 6 SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . 9 METHOD OF ANALYSIS . . . . . . . . . . . . . . . . . 10 Forward titration . . . . . . . . . . . . . . . . . . . 10 Back titration . . . . . . . . . . . . . . . . . . . . . 11 End Point determination . . . . . . . . . . . . . .
PRELIMINARY EXAMINATION Remove the instrument from the packing material and examine it carefully to make sure that no damage has occurred during shipping. If there is any noticeable damage, notify your Dealer immediately. Each titrator is supplied complete with HI 710005 or HI 710006 12VDC power adapter. PL 100C and PL 101C are also supplied with: • HI 3500A-1 10mL burette • HI 3500B reagent container • HI 3500C rubber bulb • 50mm (2”) long (dia. 7 mm/0.
GENERAL DESCRIPTION The Hanna PL 100 and PL 101 Chlorine Analyzers are amperometric titrators which allow the determination of the chlorine content in a known quantity of sample . The PL 100 measures Free Chlorine and the PL 101 Total Chlorine. The Hanna PL 100 and PL 101 Amperometric Titrators are laboratory instruments containing a precision adjustable voltage source, a microammeter with LCD display, and a speed regulated magnetic stirrer.
FUNCTIONAL DESCRIPTION FRONT PANEL 1. 2. 3. 4. 5. UP key DOWN key Power LED Stirrer ON/OFF switch LCD Display REAR PANEL 6. 7. 8. 9. 10.
FRONT PANEL Display The digital redout indicates the probe current in microamps. An overcurrent situation (greater than 1.99 µA) results in a “1.” display (no tenths or hundredths digit). To reduce probe current, merely reduce probe voltage by pressing the front panel “ ” key. Power on indicator During normal operation the red front panel indicator LED should be on continuously, indicating that the instrument is turned on.
Recorder output The recommended recorder hookup uses a shielded, twistedpair cable. The shield should be connected to (earth) ground at the recorder end and left open at the instrument end. The output is 0.00 to 2.00 V corresponding to 0.00 to 2.00 µA probe current as indicated on the front panel display. Power Power is provided from the mains through a HI 710005 or HI 710006 power adapter. Be sure the mains voltage matches the input voltage specified on the power adapter.
SPECIFICATIONS PL 100 Range Resolution Accuracy PL 101 0 - 750mVDC probe voltage 0.00 - 2.00µA probe current 0.01 µA ±0.01 µA Probe HI 3132B glass-body platinum electrode with 1 m (3.3”) cable Recorder output 0.00 to 2.00V corresponding to 0.00 to 2.00 µA Typical EMC Deviation Stirrer Motor Speed ±1% f.s. 300 ±10 RPM (constant) Power Source 12VDC through HI 710005 or HI 710006 (included) Environment 0 to 50°C (32 to 122°F); 0 to 95%RH (non condensing) Dimensions 180x180x70mm (7.1x7.1x2.
METHOD OF ANALYSIS Amperometric titration involves measuring the electrical current flow between two electrodes, usually platinum, immersed in a known quantity of a sample solution which contains an unknown concentration of the chemical to be measured. The titration of the chlorine with the reducing compound Phenylarsine Oxide (PAO) is an application of this technique.
ductant concentration and the activity ratio of the reductant to the measured substance. BACK TITRATION For waters which contain potential chemical interferences or low concentration of Total Chlorine, a back-titration is recommended. In the back-titration procedure, a known excess amount of PAO is added to the sample at pH 4 with an excess of iodide. The PAO reacts with the free chlorine and chloramines present. The amount of unreacted PAO is titrated with an iodine solution.
corded after each addition (for best results at least 3 points before and 3 points after the End Point). The End Point is determined by the intersection of the two best lines through the points. The titrant volume is multiplied by a factor to obtain the sample chlorine concentration or can be read (only in case of forward titration) straight from the graph if the PL 100/PL 101 graph-paper is used.
HOW TO SELECT THE CORRECT AMPEROMETRIC TITRATION PROCEDURE Select the procedure that best fits to your need as suggested in the block diagram below. Forward titration can be performed in two ranges: LOW RANGE when using 0.000564N PAO HIGH RANGE when using 0.00564N PAO Do not perform measurements using the forward titration method when chlorine concentration is under 0.05 mg/L. Use back titration for low concentrations of Total chlorine.
HOW TO COLLECT THE SAMPLE Free chlorine is a strong oxidizing agent and in natural waters reacts with various inorganic and organic compounds, its decomposition being influenced by parameters like reactant concentrations, pH, temperature, salinity and sunlight. Combined chlorine (chloroamines) is more stable and persistent in the environment. For best results, the delay between sample collection and analysis should be minimized.
OPERATIONAL GUIDE INITIAL PREPARATION • Connect the power supply adapter to the DC input • Connect the probe to the BNC connector. • Be sure the front stirring switch is in the OFF position and turn the instrument on by the ON/OFF switch on the rear panel. PROCEDURES Method A: free chlorine forward titration (PL100 only) 1. Fill the bottle of the automatic burette with 0.000564N PAO solution (HI 70471) for titrations up to 1500 µg/L Cl2 or use the 0.
8. Dispense the titrant into the beaker in small increments. Note the downward reading on the amperometric titrator. Record the display reading that corresponds exactly to the mL of the titrant added. Record at least 3 points before and 3 points after the End Point. 9. Construct a titration graph using the PL 100 graph paper. 10.Draw the best-fit line through each set of points. The end point is determined by the intersection of the two best lines through the points. 11.
6. Immerse the probe tip into the sample, make sure the platinum electrodes are submerged. 7. Adjust the potentiometric setting, using the “ ” and “ ” keys on the front panel until the display reads about 1.00. 8. Dispense the titrant into the beaker in small increments. Note the downward reading on the amperometric titrator. Record the display reading that corresponds exactly to the mL of titrant added. Record at least 3 points before and 3 points after the End Point. 10.
Method C: Total Chlorine back titration (PL 101 only) Instrument setting 1. Fill the bottle of the automatic burette with 0.00188N I2 solution (HI 70469) and fill the 10 ml automatic burette to the zero mark. 2. Place the stirbar into a clean 250 mL beaker and add about 200 mL deionized water. 3. Add 1 mL of pH 4 acetate buffer (HI 70467) and one spoon of potassium iodide from the bottle (HI 70468). 4. Turn on the speed controlled stirrer and place the beaker on the top of the PL 101. 5.
13.Immerse the probe tip into the sample and make sure the platinum electrodes are submerged. 14. Dispense 5 mL of titrant into the beaker. 15.Continue dispensing titrant into the beaker in small increments. Record the display reading that corresponds exactly to the mL of titrant added. Record at least 3 points before and 3 points after the End Point. 16. Construct a titration graph. 17.Draw a best-fit line through each set of points.
Note: If the sample is pretreated at the sampling site with the PAO and the acetate buffer as described before, transfer the sample quantitatively to the beaker and add one spoon of potassium iodide from the bottle (HI 70468) 22. Turn on the speed controlled stirrer and place the beaker on the top of the PL 101. 23.Immerse the probe tip into the sample, make sure the platinum electrodes are submerged. 24.Dispense the titrant into the beaker in small increments.
INTERFERENCES AND SOURCES OF ERRORS Despite Standard Methods section 4500 Cl-A.3.b. states that “the amperometric method is the method of choice because it is not subject to interferences from color, turbidity, iron, manganese, or nitrite nitrogen”, the amperometric method will detect (as all of the common chlorine methods) disinfectants such as bromine (Br2), Ozone (O3), Chlorine dioxide (ClO2), and hydrogen peroxide (H2O2).
Iodine demand of certain samples can cause a shift of the end point as shown in the following graph: The iodine, formed in case of forward total chlorine determination or added as titrant during the backward titration, can be absorbed by suspended particles or can react with organic matter. This type of interference is common in the case of muddy or highly organic-rich samples. Another source of error is due to the tendency of some metal to poison the electrodes of the titrator.
MAINTENANCE CALIBRATION REQUIREMENT Calibration of the PL 100 and PL 101 Chlorine Titrators is not required. If, for any reason, the measurements are inaccurate, contact your dealer or the nearest Hanna Customer Service Center for recalibration. PROBE CONDITIONING When the probe has not been used for some time (one week) or it is new, it is recommended that it be conditioned as follows: 1. Add a few drops of bleach to tap water in a 250 mL beaker and place the stir bar in the beaker. 2.
ACCESSORIES HI 3132B Glass-body platinum-platinum electrode with 1 m (3.3”) cable and BNC connector HI 3500A-1 10mL glass burette HI 3500B Reagent container HI 3500C Rubber bulb HI 70466 PAO Standard solution 0.00564N (for PL 101 only) HI 70467 Acetate buffer HI 70468 Potassium iodide HI 70469 Iodine standard solution HI 70470 PAO Standard solution 0.00564N (for PL 100 only) HI 70471 PAO Standard solution 0.
WARRANTY All Hanna Instruments meters are guaranteed for two years against defects in workmanship and materials when used for their intended purpose and maintained according to instructions. The electrodes and the probes are guaranteed for a period of six months. This warranty is limited to repair or replacement free of charge. Damage due to accident, misuse, tampering or lack of prescribed maintenance are not covered. If service is required, contact the dealer from whom you purchased the instrument.
OTHER PRODUCTS FROM HANNA • • • • • • • • • • • • • • • • • • • CALIBRATION AND MAINTENANCE SOLUTIONS CHEMICAL TEST KITS CHLORINE METERS CONDUCTIVITY/TDS METERS DISSOLVED OXYGEN METERS HYGROMETERS ION SPECIFIC METERS (Colorimeters) MAGNETIC STIRRERS Na/NaCl METERS pH/ORP/Na ELECTRODES pH METERS PROBES (DO, µS/cm, RH, T, TDS) PUMPS REAGENTS SOFTWARE THERMOMETERS TRANSMITTERS TURBIDITY METERS Wide Range of Accessories Most Hanna meters are available in the following formats: • BENCH-TOP METERS • POCKET-SIZE
CE DECLARATION OF CONFORMITY Recommendations for Users Before using these products, make sure that they are entirely suitable for the environment in which they are used. Operation of these instruments in residential areas could cause unacceptable interference to radio and TV equipment. The metal band at the end of the sensor is sensitive to electrostatic discharges. Avoid touching this metal band at all times.
HANNA LITERATURE Water Analysis Handbook Envirocare General Catalog PRINTED IN PORTUGAL Lab Recording h t t p : / / w w w . h a n n a i n s t . c o m MANPL100R1 07/98 These and many others catalogs, handbooks and leaflets are available from Hanna. To receive your free copy, contact your dealer or the nearest Hanna Customer Service Center.
