APERA INSTRUMENTS / LABSEN 851-H · 853-H · 855 / AI3168 / AI3180 / AI3243

Thick, salty, alkaline samples.
One pressurized electrode.

LabSen 851-H, 853-H and 855 are non-refillable pre-pressurized pH electrodes for highly viscous samples such as skin care products, coatings, syrups, resin, glue and honey, including samples with high salinity or strong alkalinity. Their HA-type membrane minimizes alkaline error. The 851-H has a BNC connector, the 853-H adds a built-in temperature sensor with an RCA plug, and the 855 is the 8-pin pH/temperature version for PH60 and PH60Z testers fitted with the required 8-pin socket/adapter.

Listed operating envelope: pH 1–14 as a conservative common range; electrode/sample temperature 0–100°C from current US standalone pages, subject to host limits. Choose the version that matches your meter’s connection and temperature requirements from the menu above. Apera warrants LabSen electrodes for six months from delivery.

BNC versions connect to the pH input of BNC pH meters. They have no temperature sensor: use a separate temperature probe supported by the host meter (Apera’s MP500 only where the meter supports it), or manual temperature entry where available.

BNC/RCA versions carry a built-in 30 kΩ NTC temperature sensor on an RCA plug for automatic temperature compensation on Apera meters with BNC and RCA inputs, such as the PH700, PH850, PH8500, PH820, PH910 and PH9500. Apera notes they may not work with other brands’ meters because the thermistor might not be compatible.

The 8-pin version is a pH/temperature electrode for Apera meters with an 8-pin socket, including the PH60, PH60-Z, PH400, PH400S and the PC400, PC400S, SX736 and SX751. PH60 and PH60Z require the appropriate installed 8-pin socket/adapter; this cabled electrode does not replace the native tester probe directly. Confirm the adapter separately; its inclusion is not implied.

Temperature figures are electrode/sample ratings, not a complete-system rating. Use a meter and temperature-compensation method rated for the actual sample temperature; keep the meter body, cable connection and adapter within their own confirmed limits. Connector fit alone does not establish temperature or ATC compatibility.

Check the specifications.

Operating envelope: pH 1–14 as a conservative common range; electrode/sample temperature 0–100°C from current US standalone pages, subject to host limits. Common construction: body lead-free glass; glass membrane HA, hemispherical; junction ceramic; reference electrolyte pre-pressurized gel KCl.

The full specification table is in the Product Specifications tab. This listing retains the current US standalone-page temperature limit rather than adopting wider 130°C manual values. It uses a conservative common pH 1–14 range because 853-H regional specifications and 855 kit sources differ at the lower endpoint. The 853-H has BNC/RCA and a 30 kΩ NTC sensor; the 851-H manual is not its instruction manual.

Keep the tip in its cap with 3M KCl storage solution whenever it is not measuring.

Never store a pH electrode in pure, deionized or distilled water.

The 851-H, 853-H and 855 are sealed and need no refilling.

These models are intended for viscous, alkaline or salty sample measurements, not as a blanket recommendation for prolonged immersion or storage in the sample. The 851-H manual both recommends alkaline samples and cautions against strong alkali; confirm suitability with Apera for the actual concentration, temperature and exposure time before demanding caustic use. The exact European 853-H manual cautions against strong acid and dehydrating media such as absolute ethanol or concentrated sulfuric acid. Keep any such exposure brief and clean carefully afterward; store the tip in 3M KCl, not the sample.

Rinse with distilled or deionized water between samples. For stubborn deposits, use Apera electrode cleaning solution, then recondition and recalibrate.