APERA INSTRUMENTS / PH700-HT / AI5019

Hot, complex and caustic baths.
Start with a junction that stays open.

The PH700-HT pairs Apera’s PH700 benchtop meter with the Swiss LabSen 863 pH/temperature electrode. Apera’s PH700-HT manual describes the 863 as designed for accurate measurement in high-temperature solutions and in complex or caustic solutions such as electroplating baths, with a PHY glass membrane, a PTFE junction and a gel KCl reference.

Choose AI5019 when the sample chemistry, rather than the meter, decides the electrode. The kit manual lists the 863 at 0–13 pH and 0–130°C. The PH700 measures temperature and compensates from 0 to 100°C, so plan compensated readings inside that window. The gel reference needs no refilling, but the tip must still be stored wet in 3M KCl.

PHY glass for heat and chemical attack

The 863’s PHY membrane is rated to 130°C and built for corrosive, complex solutions. Apera notes that hot samples still age any pH electrode faster, so keep high-temperature immersions short. It is glass: avoid impact and thermal shock.

PTFE junction

Complex baths such as plating solutions block small ceramic junctions and cause drift. The 863 uses a PTFE junction specified to resist clogging by complex chemicals. Immerse the full junction during measurement.

Gel reference, built-in temperature sensor

A KCl gel reference does not flow and needs no refilling. A 30K NTC sensor on a separate black RCA plug lets the PH700 show ATC and compensate automatically between 0 and 100°C.

Where this configuration fits.

Use the PH700-HT for electroplating and metal-finishing baths, hot process liquids and complex or caustic mixtures that foul conventional ceramic junctions, measured inside the 863’s 0–13 pH range and the meter’s 0–100°C compensation range.

Apera’s electrode manual advises against using the 863 in strong acid and strong alkali solutions, as well as dehydrating media such as absolute ethanol and concentrated sulfuric acid. For strong acids and fluoride-containing samples, compare the PH700-HF with LabSen 833; for strong alkali and high-salinity samples, the PH700-SA with LabSen 843 is the matching configuration.

Calibrate near the working temperature.
Then keep hot immersions short.

The PH700 takes one to three calibration points, and the first must always be 7.00 pH (6.86 in the NIST series). This kit ships with 4.00, 7.00 and 10.01 pH buffers for a three-point calibration across the range; for one side only, use 7.00 → 4.00 below pH 7 or 7.00 → 10.01 above it.

Apera’s PH700-HT manual asks you to calibrate in buffers at a temperature close to the sample’s whenever you measure hot solutions, and warns that high temperatures accelerate electrode aging, so minimize time in the hot sample. Automatic compensation corrects the electrode response; it does not remove real pH changes with temperature.

After a two- or three-point calibration the meter shows the electrode slope; the closer to 100%, the healthier the electrode. Use heat-resistant PPE with hot baths and let the electrode cool gradually.

Set up the bench.
Connect pH and temperature.

Screw the metal stand base to either side of the meter, fit the supporting bar, then the electrode clip. Plug the 9V adapter into the DC9V socket, clip the electrode into the holder, and connect the blue BNC plug to pH/mV and the black RCA plug to TEMP. The banana REF socket is for a separate reference electrode and is not used with this combination electrode.

To prepare the electrode, loosen the locking ring on the storage vial, pull the electrode out slowly, rinse it with pure water and blot it dry. Never rub the glass membrane. The 863 has no refill hole to open. Run at least a two-point calibration before first use.

Read the meter.
Save the readings you need.

Wait for the stable-reading smiley to appear and stay before you record a value or confirm a calibration point. Short-press M+ to save a stable reading; long-press RM to recall saved data. The PH700 stores 50 sets in total across pH and mV, each with its number, value, unit, temperature and compensation status. When memory is full the meter shows FUL; clear it in parameter P4.

MAX/MIN mode tracks the highest and lowest readings since you entered it. The meter has no documented USB or PC export, so transcribe saved values into your own records. If a calibration fails, the Er codes on screen point to the cause in Apera’s troubleshooting guide.

Four sockets, labeled.
One for each job.

The rear panel carries a Φ2 banana REF socket for a separate reference electrode, a BNC pH/mV socket for pH and ORP electrodes, an RCA TEMP socket for the temperature sensor and a Φ2.5 DC9V power socket. Fit the connector cap whenever no electrode is connected to keep the BNC clean and the readings steady.

Press MODE to switch to mV. With a pH electrode connected, mV shows the electrode’s raw potential; with an ORP electrode such as Apera’s 301Pt-C, the PH700 reads ORP directly.

No refilling.
Store the glass wet.

The 863 uses a sealed gel reference, so there is no electrolyte to top up. Store the electrode in its vial with 3M KCl soaking solution and twist the locking ring tight. Replace the solution if it becomes contaminated, and as a rule of thumb once a month.

White KCl crystals on the outside of the vial are normal; rinse them off. Never store the electrode in tap, RO, distilled or deionized water. If it happens, soak it overnight in 3M KCl and recalibrate before use.

Apera puts typical pH-electrode life at one to two years; hot caustic duty sits at the demanding end. The replacement electrode is LabSen 863, AI3176.

Clean for the contaminant.
Then rehydrate and recalibrate.

Rinse with distilled or deionized water before and after every measurement, and blot rather than wipe. For deposits that rinsing does not remove, Apera’s table matches the cleaning agent and soak time to the contaminant: dish soap water for oils and fats, Apera cleaning solution AI1166 for proteins, scale and unknown residues, 0.1M NaOH for acidic coatings, thiourea for sulfide staining.

Use a soft brush where needed. After any cleaning, soak the electrode in 3M KCl for 12–24 hours to rehydrate it, then recalibrate before measuring.

Where the electrode sits
in Apera’s range.

Apera’s application guide assigns the LabSen 861/863 to both high-temperature solutions and complex, caustic solutions such as electroplating baths. The same PH700 meter accepts any BNC/RCA LabSen electrode, so a lab that later needs a different sample type can swap the electrode rather than the meter.

Every pH electrode ages; Apera recommends replacing yours at least every one to two years, depending on use, samples and maintenance.

Check the meter limits.
Then the electrode’s.

The PH700 displays 0 to 14.00 pH at 0.01 or 0.1 resolution with ±0.01 pH ±1 digit accuracy, −1999 to 1999 mV at 1 mV (±0.1% F.S.), and temperature from 0 to 100°C at 0.1°C (±0.5°C), with automatic or manual compensation from 0 to 100°C. It runs on a DC 9V/300 mA adapter, carries an IP54 dustproof and spillproof rating, and measures 240 × 235 × 103 mm at 1 kg.

The supplied LabSen 863 sets the practical limits: 0–13 pH and 0–130°C per the PH700-HT manual, with temperature compensation capped at the meter’s 100°C. Confirm unusual chemistries against Apera’s documentation before measuring.