HI4000-47 is a package containing pH 4 and pH 7 buffer packets with chloride ions and two plastic beakers. The special pH 4 and pH 7 buffers have a chloride background to verify the inner pH glass assembly housed within the ammonia and carbon dioxide gas sensing ISEs.

Before assembling an ammonia or carbon dioxide ISE for the first time, or if reactivating after storage, the inner glass assembly should be conditioned and tested as a pH electrode. The pH buffer packets can be added to 50 mL of deionized or distilled water and the sensor assembly carefully immersed in solution. When the mV measurement in each buffer solution is stable and recorded, the mV difference can be calculated. A calculated mV difference equal or greater than 160 mV is acceptable for temperatures between 20 and 25°C.