User's Guide Oyster pH - Conductivity - TDS - Meters Models 341350 and 341350-P INTRODUCTION Congratulations on your purchase of the Extech's Oyster Series meter or meter kit. These devices measure pH, Conductivity and TDS. These meters are intended for routine laboratory and field testing. Accurate measurements are provided in a battery operated, portable meter with a hinged display that can be adjusted to any viewing angle. Model 341350 includes a glass conductivity electrode and model 341350-P includes a Polymer conductivity electrode. METER DESCRIPTION 1. LCD display 2. Battery compartment 3. Conductivity cal pot 4. pH temperature adjust 5. pH CAL and SLOPE adjustments 6. Function switch 7. Electrode connectors 8. ON/OFF switch 9. Lanyard attachment pins 10. pH electrode 11. Glass Conductivity cell 12. Polymer Conductivity cell OPERATING INSTRUCTIONS pH Calibration 1. Calibrate the meter and electrode before each use to ensure accuracy. 2. Connect the pH electrode via the BNC connector to the meter. 3. Open the meter to the fully extended position. Open the battery cover and install a 9V battery. Replace the cover and turn the unit ON. The LCD indication should appear. 4. Slide the SELECT switch to pH 5. Adjust the TEMP C knob to approximate the solution temperature. 6. Remove the wetting cap from the tip of the electrode. Rinse in de-ionized water, blot dry and place the electrode in a 7.00 pH buffer solution. Allow to stand for approximately one minute or until the display stabilizes. o 7. Adjust the CALIB knob until the display reads 7.00. 8. Remove the electrode from the buffer and rinse it in distilled water and blot dry. Place the electrode in a 4 or 10 pH buffer solution and allow to stand for approximately 1 minute or until the display stabilizes. 9. Adjust the SLOPE knob until the display reads 4.00 or 10.00 (as required). 10. Repeat steps 6 through 9 until no further adjustment is necessary. Conductivity / TDS Calibration The conductivity cell calibration should be performed frequently to ensure accuracy. 1. Connect the conductivity cell to the input socket on the side of the meter. 2. Prepare a conductivity solution of approximately the same value as the solution to be 0 measured. The solution should be prepared at 25 C. 3. Set the meter to the uS/cm or TDS mode. 4. Place the cell in calibration solution and allow the reading to stabilize. 5. Adjust the Cell knob until the display reads the value of the calibration solution. Example: For a 12560uS/cm conductivity solution the display will read 1256. The user must multiply the reading x 10. 2 341350 V2.0 10/06 pH Measurement 1. Turn the meter ON and set the function slide switch to the “pH” position. 2. Connect the pH electrode to the side BNC connector. 3. Calibrate the electrode if required. 4. Adjust the TEMP °C dial to the temperature of the sample in degrees C. 5. Place the electrode in the sample solution and read the pH value on the LCD. 6. When all measurements have been taken, unplug the electrode and rinse in distilled water, shake and store in the wetting cap or a pH 4 buffer solution. Notes on pH measurements and electrodes 1. The 60120B pH electrode is recessed in the polymer body allowing it to rest against the bottom of a beaker without damage the glass bulb. 2. The Electrode should stored in its wetting cap until used. Use a pH 4 buffer solution or tap water as the storage medium. 3. If bubbles are seen in the bulb area, hold the electrode by its cap and shake downwards until bubbles are removed. 4. To improve speed of response, vigorously stir the electrode in the sample, buffer, or rinse solution. 5. After exposure to a sample, buffer, or rinse solution, shake the electrode with a snap motion to remove residual drops of solution. 6. Use part of the next sample/buffer to be measured as a rinse solution, when possible. 7. When calibrating, use a buffer as close as possible to the expected pH of the sample. 8. Keep buffers and samples at the same temperature to avoid temperature effects. 9. pH readings stabilize faster in some solutions than others; allow time to stabilize. 10. Electrodes deteriorate over time. If accuracy falls to 10% the electrode should be cleaned or replaced. If no improvement is observed, replace the electrode. Conductivity/TDS Measurements (Multiply readings by 10) 1. Turn the meter ON and set the function slide switch to the “uS/cm” or ”TDS” position 2. Place the electrode in the sample solution. 3. Multiply the reading in the LCD display by 10. 4. When finished, unplug the electrode and rinse in distilled water. Notes on the Conductivity/TDS Cell 1. Cell Storage: On sheathed cells, replace the sheath over the cell when storing. For non-sheathed versions, soak the cell tip in de-ionized water for storage. 2. Cell Cleaning: After each use, the cell tip should be rinsed with de-ionized water. If solids build up inside the cell carefully remove with a cotton swab soaked in solvent taking care not to touch the metal parts of the inner cell. 3 341350 V2.0 10/06 pH Troubleshooting Chart Symptom Long response time or reading drift Cause Clogged Junction Recommended Solution o Soak in 4.07 M KCL @ 60 C for 30 minutes Strong Alkaline measurement Soak in 0.1 M HCL overnight Deteriorated Gel layer Protein coating on electrode surface Soak in 1 gm Pepsin dissolved in 100ml of 0.1 m HCL for 30 minutes or as needed Oil, paint, dyes, suspended solids Rinse electrode alternately with on sensor materials solvent then buffer 7.00 Organic solvents are coating sensor Dehydrated membrane Organic mole fraction has to be less than 50% to assure reasonable readings. Limit time of measurement. Keep probe in the 7.0 buffer between readings. Dry Bulb Long term storage without wetting Soak electrode tip in wetting cap filled with 1ml 7.00 buffer for 24 to 48 hours Static Charge Wiping electrodes Rinse electrode in 7.0 buffer and blot. Do no wipe electrode. Same readings in different buffers and samples Cracked or broken bulb Replace electrode. Use bulb guard. Avoid plunging electrode to bottom of container and spinning bars. A wetting cap will protect bulb between measurements. Erratic LCD display Samples have low ionic strength (lacks salt); e.g. distilled, deionized, boiled, lake water (high pressure) For each 50 ml of sample add 1 drop (50uL) of SAT.KCL No alteration in pH will occur by inert KCL. Temperature conversion table °C to °F Conversion °C °F 0 32 20 68 25 77 30 86 40 104 50 122 60 140 70 158 80 176 90 194 100 212 4 341350 V2.0 10/06 SPECIFICATIONS Range (resolution) Accuracy ± 0.5% Conductivity 10 - 19,990µS (10µS) pH 0.00 to 14.00pH (0.01pH) ± 0.02pH TDS 10 - 19,990ppm (10ppm) ± 0.5% o Auto/Manual Temperature Manual for pH/Auto for conductivity/TDS; 0-100 C; o Compensation Correction: 2% per C Power 9V battery Display 3-1/2 Digit LCD (90 to 180 adjustable viewing angle) Overrange Indication Automatic (1---) on all ranges Low Battery Indication Automatic Dimensions/Weight 3.75 x 4.25 x 2" (96 x 108 x 45mm) / 12 oz (340g) Accessories supplied 9V battery, pH electrode, pH buffers, bottle, case, and conductivity cell o MAINTENANCE Conductivity Cell Simulator The meter is supplied with a cell simulator which can be used in place of the conductivity cell to provide a means to verify the operation of the meter. The simulator will produce a reading of approximately 800 - 1200uS (~1mS). The simulator should not be used as a calibration device. This device is helpful in determining if the cause of calibration difficulties is related to the meter or (more likely) an aged or defective conductivity cell. Battery Installation / Replacement Install a new battery when the LOW BATTERY indication appears on the LCD. 1. Open the top cover (display) to its fully extended position. 2. Locate the slot below the arrow on the battery cover. 3. Use a flat bladed screwdriver or small coin to pry up and out in the slot until the cover opens. 4. Install the new battery and replace the cover. Calibration / Repair Services Extech offers complete repair and calibration services for all of the products we sell. For periodic calibration or repair of any Extech product, call customer service for details on services available. Extech recommends that calibration be performed on an annual basis to insure calibration integrity. 5 341350 V2.0 10/06 WARRANTY EXTECH INSTRUMENTS CORPORATION warrants this instrument to be free of defects in parts and workmanship for one year from date of shipment (a six month limited warranty applies on sensors and cables). If it should become necessary to return the instrument for service during or beyond the warranty period, contact the Customer Service Department at (781) 890-7440 ext. 210 for authorization or visit our website at www.extech.com (click on Contact Extech and go to Service Department to request an RA number). A Return Authorization (RA) number must be issued before any product is returned to Extech. The sender is responsible for shipping charges, freight, insurance and proper packaging to prevent damage in transit. This warranty does not apply to defects resulting from action of the user such as misuse, improper wiring, operation outside of specification, improper maintenance or repair, or unauthorized modification. Extech specifically disclaims any implied warranties or merchantability or fitness for a specific purpose and will not be liable for any direct, indirect, incidental or consequential damages. Extech's total liability is limited to repair or replacement of the product. The warranty set forth above is inclusive and no other warranty, whether written or oral, is expressed or implied. Support line (781) 890-7440 Technical support: Extension 200; E-mail: [email protected] Repair & Returns: Extension 210; E-mail: [email protected] Product specifications subject to change without notice For the latest version of this User Guide, Software updates, and other up-to-the-minute product information, visit our website: www.extech.com Extech Instruments Corporation, 285 Bear Hill Road, Waltham, MA 02451 Copyright © 2006 Extech Instruments Corporation. All rights reserved including the right of reproduction in whole or in part in any form. 6 341350 V2.0 10/06