Hanna Instruments solution for a 1000 ppm standard for calibrating a carbon dioxide ion-selective electrode, one model.
HI4005-03
This Hanna Instruments calibration solution measures a 1000 ppm standard for calibrating a carbon dioxide ion-selective electrode.
An ISE reports a ratio against a known point, so it cannot produce a number at all without a standard. Carbon dioxide is also the analyte most easily lost from an open sample, which makes a fresh standard doubly important.
A standard is only a standard while it is uncontaminated and in date. Pour what you need into a clean beaker, never dip an electrode into the bottle, and never return what you poured. Cap the bottle immediately — several of these solutions change value simply by standing open.
Write the opening date on the label. An expired or contaminated standard does not announce itself; it quietly calibrates every instrument in the laboratory to the wrong value.
Fill the vessel to the brim and cap it; headspace above a carbon dioxide sample is where the analyte goes.
Supplied as one model.