APERA INSTRUMENTS / PH8500-MS / AI5554

Small samples.
A carefully matched measuring end.

PH8500-MS pairs portable pH measurement and USB logging with the refillable LabSen 243-6 pH/temperature electrode. Its 6 mm semi-micro measuring end reaches into suitable small-sample containers without requiring a full-size electrode shaft at the sensing point. The current AI5554 configuration includes the Apera AI3303 semi-micro container, giving the conditional 60 µL method a defined container rather than an arbitrary droplet claim.

Choose this kit when sample volume and vessel access matter together. Routine small-sample use is specified for more than 0.2 mL in suitable containers; the 60 µL minimum applies only with the included compatible 6 mm semi-micro container. Both the measuring membrane and reference junction must contact the sample. A test tube in a photograph does not establish that minimum for every vessel.

Slim geometry with a defined contact requirement

LabSen 243-6 has a lead-free glass body, S-type cylindrical glass membrane, ceramic junction and Long-Life reference. Its measuring section is 6 mm in diameter and 100 mm long, but that length is not a required immersion depth or a universal vessel-fit guarantee. Position the electrode so both the measuring membrane and reference junction contact liquid. The AI3303 container is the supported accessory for the 60 µL minimum; ordinary tubes, wells or free droplets do not inherit that rating simply because the glass tip fits.

Temperature sensing is already in the electrode

The supplied 243-6 includes an NTC 30 kΩ temperature sensor. Blue BNC carries the pH signal and black RCA carries temperature, so connect both to use automatic temperature compensation. There is no separate temperature probe to add for this supplied configuration. The electrode is specified for 0–14 pH and 0–100°C, while the meter displays a wider pH interval. Keep those boundaries distinct. Automatic compensation corrects electrode response; it does not make every sample’s chemistry independent of temperature or authorize every aggressive liquid.

Small-sample results with a record

The PH8500 meter stores up to 500 data sets using manual saves or timed logging. Date, time, value, unit and temperature help retain the context of a sample run. USB PC-Link supports review and transfer; current Web PC-Link uses desktop Chrome or Edge on Windows and Mac, with CSV export and report printing. Newly logged data while connected goes to PC-Link instead of the meter memory. Export and back up before closing the session. This is not Bluetooth, ZenTest or a claim of validated compliance software.

Test tubes and narrow containers

Use the slim measuring section in suitable vessels containing more than 0.2 mL, with enough liquid to contact the membrane and junction. Check the actual container geometry before testing a valuable sample. The supplied electrode is glass, so support the vessel and avoid contact with its walls or bottom. Illustrated test tubes and liquids are props, not promised kit contents.

Volume-limited liquid samples

For the conditional 60 µL workflow, use the included AI3303 container made for a 6 mm LabSen electrode. Position the sample and measuring end according to the electrode instructions and verify both sensing contacts are wetted. This method does not support a 15 µL claim, an arbitrary droplet, a microplate well or every narrow vial.

Repeatable laboratory checks

Use clean portions of appropriate buffers and a consistent measurement sequence when comparing small samples. Minimize carryover from the preceding buffer or sample through careful rinsing. The meter’s ±0.01 pH ±1 digit accuracy is an instrument specification, not a guarantee for every formulation. Confirm suitability before strong acid, strong alkali, dehydrating media or difficult-temperature work.

Two connections.
Two sample contacts.

Lock the blue BNC connector into the pH socket and insert black RCA into the temperature socket. Remove the electrode from its storage bottle, rinse with DI or distilled water, then open the blue reference refill plug as instructed to allow electrolyte flow. Check the reference-solution level and support the glass electrode carefully. Connectors must remain clean and dry during sample preparation.

Perform at least a two-point calibration before measuring with a newly connected electrode. Start with the neutral standard for the selected buffer series and choose additional points around the expected sample. The meter supports one- to three-point automatic pH calibration. Rinse between buffers and samples, and use fresh portions so contamination is not transferred into the original bottles. Calibration liquids are required consumables, not an unverified promise of particular bottles in the MS pack.

For general small-sample work, use more than 0.2 mL in a suitable container. Use the matched AI3303 for the conditional 60 µL method, ensuring both the membrane and reference junction contact sample rather than just wetting the lowest tip. Wait for stabilization, then save the reading with its sample identity in your records. Avoid mechanical contact that could chip or break the glass.

Refill the reference.
Store the sensing end wet.

Refill the reference chamber with 3M KCl when its level falls to about half the electrode height, using the refill opening and an appropriate syringe or pipette. The blue material inside the sensing membrane is a separate proprietary gel, not the liquid you replenish. Do not replace the specified 3M KCl with Protelyte; those care instructions belong to different LabSen models. Refill tools and extra solution are not promised kit extras.

After measurement, rinse away sample residue and return the electrode to its external storage bottle containing 3M KCl. Secure the cap and close the refill plug between uses. Replace contaminated storage solution. DI or distilled water is appropriate for rinsing, but not for long-term storage of this pH electrode. Follow the electrode-specific cleaning and reconditioning procedure, then recalibrate after cleaning before trusting the next measurement.

Plan routine care around the glass membrane and ceramic junction rather than treating the reference as sealed or nonrefillable. Meter power uses three AA batteries; inclusion is unconfirmed. Current limited warranty terms cover the instrument for three years and the probe for six months from delivery, with exclusions for misuse, improper storage, wear and other causes. Neither a longer meter warranty nor a portable housing protects the glass electrode from damage.

Read the meter.
Know what is held.

Use the physical controls for standalone measurement and calibration. The stable-reading indicator and HOLD help you read a result; a held display is not an onboard measurement-history logger for later upload.

Keep the connectors and battery compartment dry when changing parts. Follow the exact manual for key sequences, battery orientation and cap sealing. Screen values in photographs are illustrative, not test results or a promise of compatibility with another sensing head.