User manual EUTECH INSTRUMENTS CALCIUM EPOXY

[. . . ] Instruction Manual Calcium Electrode EUTECH INSTRUMENTS PTE LTD. INSTRUCTION MANUAL CALCIUM ION ELECTRODE 1 Calcium Electrode Instruction Manual 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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Measuring Hints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Sample Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Units of Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 MEASUREMENT PROCEDURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [. . . ] Adjust the meter to the concentration of the calcium standard and fix the value in the memory according to the meter manufacturer's instructions after stabilization of the reading. Place the more concentrated solution on the magnetic stirrer and begin stirring at a constant rate. Adjust the meter to the concentration of the calcium standard and fix the value in the memory according to the meter manufacturer's instructions after stabilization of the reading. For low level measurements, place the rinsed, dried electrodes into a solution containing 100 ml of distilled water and 2 ml of ISA. After stabilization, fix the blank value in the meter according to the meter manufacturer's instructions. Immerse the electrode tips in the solution and wait for the reading to stabilize. Assuming no change in ambient temperature, place the electrode tips in the first calcium standard. After the reading has stabilized, compare it to the original reading in Step 3 above. A reading differing by more than 0. 5 mV or a change in ambient temperature will necessitate the repetition of Steps 2-6 above. The meter should be re-calibrated daily. 2. 3. 4. 5. 6. 7. 8. 9. Low Level Calcium Determination (using a pH/mV meter) This procedure is recommended for solutions with ionic strengths less than 1. 0X10-2M. If the solution is high in ionic strength, but low in calcium, use the same procedure, but prepare a calibration solution with a composition similar to the sample. 8 Instruction Manual Calcium Electrode 1. Dilute 10 ml of the 0. 1M standard to 1, 000 ml to prepare a 1. 0x10-3M standard solution for measurements in moles per liter. Dilute 10 ml of the 1, 000 ppm or 1 ml of the 100 ppm standard to 1, 000 ml to prepare a 10 ppm standard solution for measurements in ppm. Soak the calcium electrode for at least 1 hour in 1. 0x10-3M or 100 ppm calcium standard solution. Place the beaker on the magnetic stirrer and begin stirring at a constant rate. Add increments of the 1. 0X10-3M or 10 ppm standard as given in Table 2 below. After the reading has stabilized, record the mV reading after each addition. TABLE 2: Step-wise Calibration for Low Level Calcium Measurements Added Volume (ml) 0. 1 0. 1 0. 2 0. 2 0. 4 2 2 Concentration M ppm 1. 0X10-6 1. 0X10-2 2. 0X10-2 2. 0X10-6 -6 4. 0X10 4. 0X10-2 -6 6. 0X10 6. 0X10-2 9. 9X10-6 1. 0X10-1 -5 2. 9X10 2. 9X10-1 4. 8X10-5 4. 8X10-1 2. 3. 4. 6. Step 1 2 3 4 5 6 7 Pipet A A A A A B B Pipet A = 1 ml graduated pipet Pipet B = 2 ml pipet Solutions: additions of 1. 0x10-3M or 10 ppm standard to 100 ml of distilled water. On semi-logarithmic graph paper, plot mV reading (linear axis) against the concentration (log axis) as in Figure 1. Measure out 100 ml of the sample into a 150 ml beaker and place the beaker on the magnetic stirrer and begin stirring. After the reading has stabilized, record the mV reading and determine the concentration from the low level calibration curve. Check the calibration curve every 1-2 hours by repeating Steps 2-7 above. 8. [. . . ] To adjust the background ionic strength to a high and constant value, ionic strength adjuster (ISA) is added to samples and standards. The recommended ISA for calcium is potassium chloride, KCl. 14 Instruction Manual Calcium Electrode Solutions other than this may be used as ISA's as long as ions that they contain do not interfere with the electrode's response to calcium ions. When two solutions of different composition are brought into contact with one another, liquid junction potentials arise. Millivolt potentials occur from the inter-diffusion of ions into the two solutions. [. . . ]