APERA INSTRUMENTS / LABSEN 241-6 · 243-6 · 246-5 / AI3103 / AI3117 / AI3235

A Ø6 mm tip
for test tubes and small samples.

LabSen 241-6, 243-6 and 246-5 have a slim Ø6 mm sensing section for test tubes and small-volume samples above 0.2 mL; with Apera’s semi-micro container the smallest test volume is 60 µL. The 241-6 (BNC) and 243-6 (BNC/RCA with temperature) are refillable; the 246-5 is the non-refillable 8-pin pH/temperature version for PH60/PH60-Z testers with the compatible 8-pin adapter/socket installed.

It reads pH 0 to 14 from 0 to 100°C. Choose the version that matches your meter’s connector from the menu above. Apera warrants LabSen electrodes for six months from delivery.

BNC versions plug into any pH meter with a BNC input. They have no temperature sensor, so pair them with a separate temperature probe such as Apera’s MP500 where compatible with the meter, for automatic temperature compensation; manual temperature entry is an option only if the meter supports it at the sample temperature. Electrode ratings do not extend the meter’s or separate temperature probe’s operating or compensation limits.

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/PH60-Z testers require the compatible 60/60-Z-series 8-pin connection adapter/socket to be installed; a standard tester is not a direct plug-in host. Confirm adapter inclusion before ordering. The electrode’s temperature rating does not expand the connected meter’s measurement or compensation range.

Check the specifications.

All versions share: pH range 0–14; temperature range 0–100°C; body lead-free glass; junction ceramic.

Reference electrolyte: 241-6 3M KCl; 243-6 3M KCl; 246-5 gel KCl.

Dimensions: 241-6 and 243-6 each have a Ø6 × 100 mm measuring end. Their current manuals specify a Ø12 × 148 mm body; current product pages use a nominal 150 mm length. Confirm clearance for a tight-fitting vessel. The 246-5 is Ø12 × 120 mm with a Ø6 mm sensor tip; the 100 mm narrow-section length does not apply to it.

The full specification table is in the Product Specifications tab.

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 241-6 and 243-6 are refillable: keep the fill hole open while measuring and top up the reference electrolyte when the level drops.

The 246-5 is sealed and needs no refilling.

Apera’s manual advises avoiding strong acids, strong alkalis and dehydrating media such as absolute ethanol or concentrated sulfuric acid; if exposure is unavoidable, keep immersion short and clean the electrode carefully afterward.

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