Instruction Manual Cyanide Electrode EUTECH INSTRUMENTS PTE LTD.
Cyanide Electrode Instruction Manual TABLE OF CONTENTS GENERAL INSTRUCTIONS .......................................................................................................... 3 Introduction ..............................................................................................................................................3 Required Equipment.................................................................................................................................
Instruction Manual Cyanide Electrode EUTECH INSTRUMENTS PTE LTD. CYANIDE ION ELECTRODE INSTRUCTION MANUAL GENERAL INSTRUCTIONS Introduction Eutech Instruments Cyanide Ion Electrode is used to measure cyanide ions in aqueous solutions quickly, simply, accurately, and economically. *IMPORTANT NOTICE* Acidic cyanide solutions produce hydrogen cyanide (HCN) gas, highly toxic whether breathed or absorbed through the skin.
Cyanide Electrode Instruction Manual 3. Cyanide Standard, 1X10-2M. To prepare this solution from your own laboratory stock, add 10 ml of ISA and about 500 ml of distilled water to a one liter volumetric flask. Add 0.49 grams of dry, reagent-grade sodium cyanide, NaCN, to the solution and swirl the flask gently to dissolve the solid. Dilute to the mark with distilled water, cap, and upend the flask several times to thoroughly mix the contents. Store all standards in plastic bottles and prepare weekly. 4.
Instruction Manual Cyanide Electrode 1. Prepare standard cyanide solutions whose concentrations vary by tenfold. Use either the 1.0X10-2M or the 1,000 ppm cyanide standard. Use the serial dilution method for this preparation. 2. To a 150 ml beaker, add 100 ml of the lower value standard and 1 ml of ISA. Place the beaker on a magnetic stirrer and begin stirring at a constant rate. Lower the electrode tips into the solution. Assure that the meter is in the concentration mode. 3.
Cyanide Electrode Instruction Manual All samples must be aqueous and not contain organics which can dissolve the epoxy electrode body and/or the cement bonding the sensing crystal to the electrode body. Infrequent measurements in solutions containing methanol, benzene, or acetonitrile are permitted. Highly polar solvents slowly attack the epoxy body electrode. Please check with Eutech Instruments Pte Ltd. before using the electrode in other solvents.
Instruction Manual Cyanide Electrode NaOH (ISA). After assuring that the meter is in the mV mode, lower the electrode tips into the solution. After the reading has stabilized, record the mV reading. 3. Place 100 ml of the mid-range solution in a 150 ml plastic beaker. Place the beaker on the magnetic stirrer and begin stirring at a constant rate. Add 1 ml of 10M NaOH (ISA). After rinsing the electrodes with distilled water, blot dry, and lower the electrode tips into the solution.
Cyanide Electrode Instruction Manual 7. For low level measurements (below 8X10-6M or 0.2 ppm), place the rinsed, dried electrodes into a solution containing 100 ml of distilled water and 1 ml ISA. After stabilization, fix the blank value in the meter according to the meter manufacturer's instruction. 8. After rinsing the electrodes and blotting dry, place the electrode tips into 100 ml of the sample and 1 ml of ISA. After stabilization, read the concentration directly from the meter display. 9.
Instruction Manual Cyanide Electrode 4. On a semi-logarithmic paper, plot the concentration (log axis) against the millivolt reading (linear axis) as in Figure 1. Reserve the final solution for checking the electrode each hour. 5. To a 150 ml plastic beaker, add 100 ml of sample and 1 ml of ISA. Place the beaker on the magnetic stirrer and begin stirring at a constant rate. After rinsing the electrodes, blot dry and lower the electrode tips into the solution.
Cyanide Electrode Instruction Manual Using Table 3, the maximum ratio is: [Br-1] ———— = 5X103 [CN-1] [Br-1] = 5X103 [CN-1] = (5X103) (1X10-5) [Br-1] = 5X10-2M = maximum bromide concentration for no interference Complexation Total concentration, Ct, consists of free ions, Cf, and complexed or bound ions, Cc, in solutions: Ct = Cf + Cc Since the electrode only responds to free ions, any complexing agent in the solution reduces the measured concentration of ions.
Instruction Manual Cyanide Electrode TABLE 4: Temperature vs. Values for the Electrode Slope Temp.(oC) 0 10 20 25 30 40 50 "S" 54.20 56.18 58.17 59.16 60.15 62.13 64.11 If changes in temperature occur, the electrodes should be re-calibrated. The temperature range for the cyanide electrode is 0o-80oC, provided that temperature equilibrium has occurred. If the temperature varies substantially from room temperature, equilibrium times up to one hour are recommended.
Cyanide Electrode Instruction Manual Limits of Detection Cyanide levels from 5X10-6M to 1X10-2M cyanide can be measured with the cyanide electrodes. However, since cyanide ion attacks the electrode membrane, measurements above 1X10-3M should be done only intermittently. The electrodes respond to cyanide in the sample as well as to ions dissolved from the membrane at low levels. The electrode membrane shows a very slight water solubility. The detection limit of the electrode is determined by this factor.
Instruction Manual Cyanide Electrode Electrode Operation Eutech Cyanide Ion Electrodes consist of a solid membrane containing a mixture of inorganic silver compounds bonded into the tip of a glass or epoxy electrode body. An electrode potential develops across the membrane when the electrode is in contact with solution containing cyanide ions and is capable of measuring free cyanide ions. This potential is measured against a constant reference potential, using a standard pH/mV meter or an ion meter.
Cyanide Electrode Instruction Manual ions diffuse at different rates. When making measurements, it is important to remember that this potential be the same when the reference is in the standardizing solution as well as in the sample solution or the change in liquid junction potential will appear as an error in the measured electrode potential. The composition of the liquid junction filling solution in the reference electrode is most important.
Instruction Manual Cyanide Electrode - Measure correctly and accurately. - Review TROUBLESHOOTING HINTS. Standards and Reagents Whenever problems arise with the measuring procedure that has been used successfully in the past, be sure to check the standard and reagent solutions. If in doubt about the credibility of any of the solutions, prepare them again.
Cyanide Electrode Instruction Manual TROUBLESHOOTING HINTS Symptom Out of Range Reading Noisy or Unstable Readings (readings continuously or rapidly changing) Drift (reading slowly changing in one direction) Possible Causes defective meter Next Step check meter with shorting strap (see meter instruction manual) defective electrode electrodes not plugged in properly check electrode operation unplug electrodes and reset reference electrode not filled be sure reference electrode is filled air bubble
Instruction Manual Low Slope or No Slope "Incorrect Answer" (but calibration curve is good) Cyanide Electrode standards contaminated or incorrectly made prepare fresh standards ISA not used use recommended ISA standard used as ISA use ISA electrode exposed to complexing agents check section entitled air bubble on membrane remove bubble by re-dipping probe incorrect scaling of semi-log paper plot millivolts on the linear axis.
Cyanide Electrode Instruction Manual SPECIFICATIONS Concentration Range: 1X10-2M to 5X10-6M 260 to 0.1 ppm pH Range: 11-13 Temperature Range: 0o-80oC Resistance: <1 Mohms Reproducibility: ±2% Size: 110 mm length; 12 mm diameter; 1 m cable length Storage: store in cyanide standard with ISA added ORDERING INFORMATION CODE NO.
