Go Direct^® Calcium Ion-Selective Electrode (GDX-CA)
Specifications and User Guide

TROUBLESHOOTING
-Primary Test: Check the readings in the standards. The high should be around 1000 mg/L. The low should be around 10 mg/L.
-Secondary Test: Refer to General tips for using Ion Selective Electrodes (ISE).

RELATED TIL ENTRIES
–Do any of your sensors require special storage?
–Do you sell ISE Standards?
–General tips for using Ion Selective Electrodes (ISE).
–How do I sterilize an Ion-Selective Electrode?

SPECIFICATIONS
-Range: 1 to 40,000 mg/L or ppm
-pH range: 3 to 10
-Interfering ions: Pb2+, Hg2+, Si2+, Fe2+, Cu2+, Ni2+, NH3, Na+, Li+, Tris+, K+, Ba2+, Zn2+, Mg2+
-Electrode slope: +28 mV/decade
-Approximate calibration voltages: 80 mV in 1000 mg/L, 30 mV in 10 mg/L
-Accuracy: ± 10% of full scale (calibrated 10 to 1000 mg/L)
-Temperature range (can be placed in): 0 to 40°C (no temperature compensation)
-Minimum immersion: 1.1 inch
-dimension ISEA: 8.5 cm height x 3 cm wide x 1.75 cm depth
-dimension electrode: 15.5 cm length, 12 mm OD
-shaft diameter: 12mm OD

CALIBRATION
-Calibrate? Yes. Conduct a two-point calibration, using the standard solutions that are shipped with the sensor. First point: The ISE should be soaking in the High Standard. Enter the concentration value of the High Standard. Second point: Remove the ISE from the High Standard, rinse well with distilled water from a wash bottle, and gently blot dry with a paper towel or lab wipe. Place the electrode into the Low Standard. Wait for the relative stability reading to stabilize. Enter the concentration value of the Low Standard.
-Important: Make sure the ISE is not resting on the bottom of the container, and that the small white reference contacts are immersed. Make sure no air bubbles are trapped below the ISE. Hold the ISE still and wait for the voltage reading to stabilize. Stirring the solution during this process is ideal.

BATTERY TROUBLESHOOTING
If the sensor can be turned on when connected by USB but not when disconnected from USB, the battery either needs charging or has reached its end of life and can no longer hold a charge. First, try charging the sensor for several hours. If the sensor still won’t turn on when disconnected from USB, the battery has likely reached its end of life. If you intend to use this sensor wirelessly, the battery will need to be replaced. The rechargeable battery in this sensor is covered by a one year warranty but should last two to five years in typical use.
How do I replace the battery in a Go Direct Wand-Type Sensor?

RELATED VERNIER PRODUCTS
-ISE Calcium Replacement Module, Calcium Replacement Module (CA-MOD)
-ISE Calcium Low Standard, Standard Ca ISE Solution (CA-LST)
-ISE Calcium High Standard, Standard Ca ISE Solution (CA-HST)