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Summary of Contents for EUTECH INSTRUMENTS FLUORIDE EPOXY
- Page 1 Instruction Manual Fluoride Electrode EUTECH INSTRUMENTS PTE LTD. INSTRUCTION MANUAL FLUORIDE ION ELECTRODE...
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Page 2: Table Of Contents
Instruction Manual Fluoride Electrode TABLE OF CONTENTS GENERAL INSTRUCTIONS ......................3 Introduction................................... 3 Required Equipment ..............................3 Required Solutions................................ 3 GENERAL PREPARATION......................4 Electrode Preparation..............................4 Electrode Slope Check (with pH/mV meter) ........................ 4 Electrode Slope Check (with ion meter) ........................5 MEASUREMENT.......................... -
Page 3: General Instructions
FLUORIDE ION ELECTRODE INSTRUCTION MANUAL GENERAL INSTRUCTIONS Introduction Eutech Instruments Fluoride Ion Electrode is used to measure fluoride ions in aqueous solutions quickly, simply, accurately, and economically. Required Equipment A pH/mV meter or an ion meter, either line operated or portable. -
Page 4: General Preparation
Instruction Manual Fluoride Electrode Eutech Total Ionic Strength Adjuster Buffer (TISAB 1), Code No. EC-ISA-FL1-BT. TISAB 1 is used to adjust the pH of the solution, de-complex fluoride and provide a constant background ionic strength. To prepare this solution from your own laboratory stock, half fill a four liter beaker with distilled water. -
Page 5: Electrode Slope Check (With Ion Meter)
Instruction Manual Fluoride Electrode Slope is defined as the change in potential observed when the concentration changes by a factor of Electrode Slope Check (with ion meter) (Check electrodes each day) Prepare standard fluoride solutions whose concentrations vary by tenfold. Use either the 0.1M, 1,000 ppm, or 100 ppm fluoride standard. -
Page 6: Sample Requirements
Highly polar solvents, such as CHCl or DMF, should not be contained in the samples. Please check with Eutech Instruments Pte Ltd. before using the electrode in other organic solvents. The addition of TISAB to samples and standards will adjust the pH to 5.0-5.5. Samples must be above pH 5 to avoid forming complexes with hydrogen ions and below pH 7 to avoid interference by hydroxide ions. - Page 7 Instruction Manual Fluoride Electrode Place the mid-range solution on the magnetic stirrer and begin stirring. After rinsing the electrodes with distilled water, blot dry, and immerse the electrodes in the solution. When the reading has stabilized, record the mV value. Place the most concentrated solution on the magnetic stirrer and begin stirring.
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Page 8: Direct Measurement Of Fluoride (Using An Ion Meter)
Instruction Manual Fluoride Electrode Direct Measurement of Fluoride (using an ion meter) By serial dilution of the 0.1M, 1,000 ppm, or 100 ppm fluoride standard, prepare two fluoride standards whose concentration is near the expected sample concentration. Add 50 ml of TISAB 1 or TISAB 2, to each 50 ml of standard. When calibrating, assume that the added TISAB has no effect on the standard concentration. -
Page 9: Direct Measurement Of Fluoride In Acid Solutions
Instruction Manual Fluoride Electrode Prepare 2, 1, and 0.5 ppm fluoride standards by serial dilution of the 100 ppm fluoride standard. To each 50 ml of standard, add 50 ml of TISAB 1 or TISAB 2. Calibrate the meter as previously described by using the 2, 1, and 0.5 ppm standards. -
Page 10: Low Level Fluoride Measurements (Using A Ph/Mv Meter)
Instruction Manual Fluoride Electrode section (Determination of Fluoride in Following the directions given in the preceding Acid Solutions ), prepare standards, calibrate the electrodes and measure the unknown samples. Low Level Fluoride Measurements (using a pH/mV meter) Use the following low level fluoride measurement procedure in the non-linear portion of the calibration curve. -
Page 11: Low Level Fluoride Determination (Using An Ion Meter)
Instruction Manual Fluoride Electrode Low Level Fluoride Determination (using an ion meter) Follow the previous procedure for fluoride measurements with an ion meter, except use low level TISAB 2 instead of TISAB 1. Always use the blank correction. -
Page 12: Titration
Instruction Manual Fluoride Electrode Titration Titration is a very accurate determination of fluoride. Eutech Fluoride Ion Electrodes can be used as highly sensitive endpoint detectors for titration of a fluoride-containing sample. Though titration are more time consuming than direct ion measurements, the results are more accurate and reproducible. Titration accurate to ±0.2% of the total fluoride concentration of the sample can be performed using lanthanum nitrate as the titrant. -
Page 13: Electrode Characteristics
Instruction Manual Fluoride Electrode C s = concentration of sample C s = fluoride standard concentration (0.1M) V t = volume of titrant added to achieve the endpoint of unknown sample V t = volume of titrant added to achieve the endpoint in standardization V f = volume of sample used in sample titration V f = volume of standard used in standardization titration. -
Page 14: Complexation
Instruction Manual Fluoride Electrode Complexation Hydrogen ion, as well as some other multivalent cations, aluminum, silicon, iron , will form complexes with fluoride. The total ionic strength of the solution, the pH of the solution, the total fluoride concentration, and the concentration of the complexing agent all contribute to the degree of complexation. -
Page 15: Limits Of Detection
Instruction Manual Fluoride Electrode A drifting potential reading or a decrease in electrode slope may mean that the electrode membrane needs polishing. To polish the membrane: If using polishing paper, cut off a 1-2" piece and place it face up on the lab bench. Put a few drops of distilled or deionized water in the center of the paper. -
Page 16: Electrode Life
Instruction Manual Fluoride Electrode When the level of hydroxide is greater than one-tenth the level of fluoride ion present, hydroxide ion interferes with electrode response to fluoride. As an example, no hydroxide interference with fluoride measurements take place at pH 7 when the hydroxide concentration is 1.0X10 or less. -
Page 17: Electrode Storage
Instruction Manual Fluoride Electrode Electrode Storage The fluoride electrode may be stored for short periods of time in 1.0X10 M fluoride solution with TISAB added. For longer storage (longer than two weeks), rinse and dry the sensing pellet and cover the membrane tip with any protective cap shipped with the electrode. The reference portion of the combination electrode (or the outer chamber of the reference electrode) should be drained of filling solution, if refillable, and the rubber insert placed over the filling hole. -
Page 18: Troubleshooting Guide
Instruction Manual Fluoride Electrode In the case of high and constant ionic strength relative to the sensed ion concentration, the activity coefficient, γ, is constant and the activity, X, is directly proportional to the concentration. All samples and standards containing fluoride ions have TISAB added so that the background ionic strength is high and constant relative to variable concentrations of fluoride. -
Page 19: Standards And Reagents
GENERAL PREPARATION Refer to the instruction manual again. Reread the sections ELECTRODE CHARACTERISTICS. If trouble still persists, call Eutech Instruments Pte Ltd. at (65) 6778-6876 and ask for the Customer Services Department. -
Page 20: Troubleshooting Hints
Instruction Manual Fluoride Electrode TROUBLESHOOTING HINTS Symptom Possible Causes Next Step Out of Range defective meter check meter with shorting strap Reading (see meter instruction manual) defective electrode check electrode operation electrodes not plugged unplug electrodes and reset in properly reference electrode be sure reference electrode is not filled... - Page 21 Instruction Manual Fluoride Electrode Complexation to complexing agents air bubble on membrane remove bubble by re-dipping probe "Incorrect Answer" incorrect scaling plot millivolts on the linear axis. (but calibration of semi-log paper On the log axis, be sure that curve is good) concentration numbers within each decade are increasing with increasing concentration...
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Page 22: Specifications
Instruction Manual Fluoride Electrode SPECIFICATIONS Concentration Range: Saturated solutions to 1.0X10 (saturated solutions to 0.02 ppm) pH Range: 5 to 7 at 1.0X10 (0.02 ppm F 5 to 11 at 1.0X10 (1900 ppm F Temperature Range: to 80 to 100 C intermittent use) Resistance: 150-200 kohm...
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