Apera PH700 Benchtop pH Meter Instruction Manual

1 Brief Introduction

Thank you for purchasing the Apera Instruments PH700 Benchtop pH meter. This instrument combines advanced electronics design and sensor technology, offering an economical and reliable lab-grade benchtop pH meter. Please read this manual carefully for proper use and maintenance. Apera Instruments reserves the right to update the manual's contents without prior notice.

1.1 Main Features

• The meter features a built-in microprocessor chip enabling intelligent functions such as automatic calibration, automatic temperature compensation, data storage, parameter setup, and max/min reading display.
• The advanced automatic calibration mode includes a calibration guide and self-diagnosis functions, automatically recognizing standard buffer solutions (USA or NIST series).
• Advanced digital processing technology enhances response time and measurement accuracy with a stable reading display mode.
• The kit includes a 3-in-1 combination pH Electrode that measures pH and temperature simultaneously.
• The instrument is IP54 dustproof and spillproof, with connectors protected by silicone seal caps for reliability in harsh environments.
• A detachable electrode holder and three bottles of pH buffer solutions are included for convenient use.

2 What's in the Box?

3 Technical Specifications

4 Instrument Description

4.1 LCD Display

The LCD display shows various measurement values, icons, and status indicators. Key elements include:

• (1) Measurement value: Displays the current pH or mV reading.
• (2) Calibration icons and numberings: Indicates calibration status and step.
• (3) Measurement unit: Shows the unit (pH or mV).
• (4) Temperature and reminder icons: Displays temperature and other status reminders.
• (5) pH unit during calibration: Shows the pH value being calibrated.
• (6) pH value during calibration: Displays the calibration buffer value and storage/recall numberings.
• (7) Data storage and recall icons: M+ for storing data, RM for recalling data.
• (8) Self-Diagnosis icons and numberings: Indicates error codes or diagnostic information.
• (9) Temperature compensation mode icons: ATC for Auto Temperature Compensation, MTC for Manual Temperature Compensation.
• (10) Completed calibration icons: Indicates successful calibration steps.
• (11) Stable reading icon: A smiley face ? indicates a stable measurement.
• (12) Icons for maximum and minimum values: Indicates max/min reading mode.

Diagram Description: Figure-1 illustrates the Apera PH700 pH meter's LCD display with numbered indicators pointing to different functional areas and icons.

4.2 Keypad

The keypad provides control for all meter functions. Operations are categorized by short press (<1.5 seconds) and long press (>1.5 seconds).

4.3 Connectors

The meter features various connectors for electrodes and power:

Diagram Description: An illustration shows the rear panel of the pH meter with labeled sockets for REF, pH/mV, TEMP, and DC9V power input.

4.4 Stable reading display mode

When a measurement is stable, a smiley face icon ? appears on the LCD. Calibration or recording should only be performed when this icon is visible and remains steady.

Figure-3 shows the LCD displaying a stable pH reading with the smiley face icon ?.

Figure-4 shows the LCD after data has been stored, displaying the M+ icon and storage numberings.

4.5 Data storage, recall, and deletion

Storage: When the measurement is stable, press the M+ RM key. The meter displays the M+ icon and storage numberings, saving the current measurement. Pressing M+ RM again continues storing data.

Recall stored data: In measurement mode, long press the M+ RM key to recall the last stored measurement. The meter displays the RM icon and storage numberings. Use the ▲ and ▼ keys to scroll through stored data. Press and hold ▲ or ▼ to scroll quickly. Short press CAL MEAS to return to measurement mode.

Clear stored data: The meter can store up to 50 groups of data. If storage is full, pressing M+ RM will display a FUL icon. Data can be cleared via parameter setting P4.

Figure-5 shows the LCD displaying recalled data with the RM icon and a specific data number (e.g., 28).

Figure-6 shows the LCD indicating that the storage is full, displaying the FUL icon.

The numberings for M+ indicate the total stored data across all modes. The numberings for RM indicate data stored within the current mode (pH or mV). For example, if 20 groups are stored in pH mode and 10 in mV mode, M+ will show "M+30", RM in pH mode will be "RM20", and in mV mode "RM10".

4.6 Max/Min Function

This function displays the maximum or minimum recorded values from a series of measurements. In measurement mode, press the MAX MIN key; the LCD will show flashing MAX/MIN icons. After testing, pressing MAX MIN again will alternately display the maximum and minimum values. Press CAL MEAS to return to regular measurement mode.

5 pH Measurement

5.1 Preparation

Install the electrode holder

The electrode holder consists of a metal stand base, a supporting pole, and an electrode clip. Attach the metal stand base to the meter (screw it on), ensuring it can be installed on either side. Then, attach the supporting bar to the base and the electrode clip to the supporting bar.

Connect the power adapter

Plug the power adapter into the DC9V socket. Ensure the adapter's voltage meets the meter's requirements.

Things needed in addition to what's included in the box

A clean cup, distilled water (8-16oz), and tissue papers for rinsing and drying the probe are required.

5.2 pH Electrode Information

pH Electrode

The meter is supplied with a 201T-F 3-in-1 combination electrode featuring a built-in temperature sensor for automatic temperature compensation. This electrode is suitable for regular water solutions. For specific applications, refer to Section 7. The electrode housing is made of polycarbonate, offering resistance to shocks and corrosion. A 3M KCL storage bottle is provided to maintain electrode sensitivity when not in use.

Technical Specifications of the 201T-F pH Electrode

• Measurement Range: 0 - 14 pH, 0 - 80°C (32 – 176°F)
• Junction: Single Ceramic
• Reference Electrode: Ag/AgCl
• Connector: BNC/RCA
• Size: Ø12*160 mm
• Temperature unit: 30K Thermistor

Electrode Connectors

The pH electrode has two connectors: the BNC connector for the pH probe and the RCA connector for the temperature sensor. Connect these to the 'pH/mV' and 'TEMP' sockets respectively. Avoid pulling the cables to prevent poor contact. Keep connectors clean and dry. Refer to section 4.7 for maintenance.

Use the Electrode

Remove the electrode from its KCL storage bottle (do not spill the solution). Rinse the electrode in distilled water for a few seconds. Gently shake off excess water and pat dry with clean tissue paper (do not rub). Stir the electrode gently in the sample solution for a few seconds, then let it stand still until a stable reading (indicated by ? icon) is achieved. Record the reading. After testing, place the electrode back into the storage bottle and tighten the cap to preserve its sensitivity.

5.3 Information regarding Calibration

pH buffer solutions

The meter supports two series of standard buffer solutions: USA and NIST, selectable via parameter P1 (see 4.6.1). Calibration can be performed using 1, 2, or 3 points.

Table-2 lists the standard buffer solutions for USA and NIST series, associated with calibration icons [L], [M], and [H].

3-Point Calibration

Calibration can be performed using 1, 2, or 3 points. The first point must use the 7.00 pH (or 6.86 pH) buffer. Subsequent points use other buffers. The calibration process displays the slope of acidity and alkalinity ranges, indicating probe health; a slope closer to 100% signifies better probe condition.

Table-3 details the calibration modes, corresponding buffer solutions, icons, and recommended usage scenarios.

How often to calibrate

Calibration frequency depends on the samples, electrode condition, and accuracy requirements. For high-accuracy measurements (≤ ±0.02pH), calibrate before each test. For ordinary-accuracy measurements (≥ ±0.1pH), calibration is typically valid for about a week. Recalibration is necessary if:

• The electrode has not been used for a long time or a new electrode is connected.
• After measuring strong acid (pH<2) or strong base (pH>12) solutions.
• After measuring fluoride-containing or strong organic solutions.
• There is a significant temperature difference between the test sample and the buffer solution used in the last calibration.

5.4 pH Meter Calibration

Follow these steps for pH meter calibration:

1. Press CAL MEAS to enter calibration mode. The CAL1 icon and '7.00 pH' will flash, indicating the first calibration point.
2. Rinse the electrode with distilled water and pat dry. Dip it into the pH 7.00 buffer solution, stir gently, and wait for a stable reading (indicated by ?). The meter will show the buffer recognition process. Pressing ENTER before recognition may result in an 'Er2' error.
3. When the meter recognizes 7.00 pH and the ? icon appears, press ENTER to calibrate. An 'End' icon confirms completion. The CAL2 icon will flash, and '4.00 pH'/'10.01 pH' will alternate, prompting for the second calibration point.
4. Rinse and dry the electrode. Dip it into the pH 4.00 buffer solution, stir gently, and wait for a stable reading. When 4.00 pH is recognized (? icon appears), press ENTER to calibrate. The 'End' icon and the electrode slope will be displayed. The CL3 icon will flash, and '10.01 pH' will appear, prompting for the third calibration point.
5. Rinse and dry the electrode. Dip it into the pH 10.01 buffer solution, stir gently, and wait for a stable reading. When 10.01 pH is recognized (? icon appears), press ENTER to calibrate. The 'End' icon and the electrode slope of alkalinity range will be displayed. The meter returns to measurement mode with calibration icons L M H shown.
6. Press CAL MEAS at any time to exit calibration mode. The meter supports one-point, two-point, and three-point calibrations.

Figure-7 illustrates the LCD display sequence during a 3-point calibration process.

5.5 Measuring pH

To measure pH:

1. Remove the electrode from its storage bottle. Rinse with distilled water and pat dry.
2. Gently stir the electrode in the sample solution for a few seconds, then let it stand still.
3. Wait for the stable measurement indicator (? icon) to appear and remain steady.
4. Record the reading.

Figure-8 provides a flowchart outlining the calibration and measurement process.

Notes:

1. The default 201T-F electrode may not provide accurate readings for purified water (distilled or deionized) due to low ion concentration. For such samples, a specialized electrode like the LabSen™ 803 Pure Water pH Electrode is recommended. Contact Apera Instruments for details. Testing purified water like spring or drinking water may require longer stabilization times (3-5 minutes) due to fewer ions.
2. Distilled or deionized water is recommended only for rinsing the probe.
3. The 201T-F electrode is not suitable for high-temperature samples (>176°F), as it may cause permanent damage. Use specialized electrodes like LabSen™ 213 (up to 225°F) for such applications.
4. The electrode housing is polycarbonate. Avoid cleaning agents like carbon tetrachloride, trichlorethylene, tetrahydrofuran, or acetone, as they can dissolve the housing.

For best results, the test sample's temperature should be close to the calibration solution's temperature. For samples at 150°F, warm calibration solutions to the same temperature before calibrating.

The instrument has a factory default reset function (parameter P5, section 5.6). This restores theoretical values (pH 7.00, slope 100%) and default settings. Use this function if calibration or measurement is abnormal. This reset is irreversible.

5.5.3 Self-Diagnosis

The meter performs self-diagnosis during calibration and measurement. Error codes and their solutions are listed below:

Note: An air bubble in the pH sensor's glass bulb can significantly decrease measurement stability. Gently shake the probe to remove it.

5.6 Parameter Setting

The meter allows adjustment of various parameters:

How to do the parameter setting:

From measurement mode, long press MODE SETUP to enter parameter setting P1. Use ▲ or ▼ to navigate through P1 to P5.

5.7 pH Electrode's Maintenance

5.7.1 Daily maintenance

The soaking solution in the protective bottle maintains electrode activation. Loosen the cap, remove the electrode, and rinse it in distilled water before measurement. Reinsert and tighten the cap after use. If the soaking solution becomes cloudy or moldy, replace it with fresh 3M KCL solution.

Note: Do not use other brands' soaking solutions, as incompatible chemicals may damage the electrode.

Note: The electrode should not be soaked or stored in purified/distilled water, protein solutions, acid fluoride solutions, or organic lipids. Distilled or purified water is only for rinsing.

5.7.2 Calibration buffer solution

For accurate calibration, use reliable buffer solutions. Refresh them frequently, especially after heavy use. It is recommended to replace buffers after 10-15 uses.

5.7.3 Protect glass bulb

The sensitive glass bulb should not contact hard surfaces, as scratches or cracks can cause inaccurate readings. Rinse the electrode with distilled or purified water before and after each measurement. If the electrode is contaminated, clean it with a soft brush and mild soap, rinse with distilled water, and soak in KCL solution for at least 6 hours.

5.7.4 Renew glass bulb

Aged electrodes can be renewed. Submerge the electrode in 0.1mol/L hydrochloric acid for 24 hours, rinse in distilled water, then soak in KCL solution for 24 hours. To prepare 0.1mol/L HCl: dilute 9mL HCl in distilled water to 1000mL. For serious passivation, briefly submerge the bulb in 4% HF for 3-5 seconds, rinse in distilled water, and soak in KCL solution for 24 hours.

5.7.5 Clean contaminated glass bulb and junction

6 mV measurement

6.1 ORP measurement

To switch to mV measurement mode, press the MODE SETUP key. Connect an ORP electrode (e.g., 301Pt-C, sold separately) and dip it into the sample solution. Stir briefly and allow it to stabilize until the ? icon appears. ORP stands for Oxidation Reduction Potential, measured in mV.

6.2 Notes on ORP measurement

6.2.1 ORP measurement

ORP measurement does not require calibration. To verify electrode or meter performance, use an ORP standard solution. Table-9 provides data for a standard ORP solution at 222 mV.

Table-9 shows the mV values of a standard ORP solution at various temperatures.

6.2.2 Clean and activate ORP electrode

Polluted platinum surfaces on ORP electrodes can cause inaccurate measurements and slow response. Follow these cleaning methods:

1. For inorganic pollutant: Submerge the electrode in 0.1mol/L dilute hydrochloric acid for 30 minutes, rinse in distilled water, then soak in the KCL solution for 6 hours.
2. For organic or lipid pollutant: Clean the platinum surface with detergent, rinse in distilled water, then soak in the KCL solution for 6 hours.
3. For heavily polluted platinum surface (oxidation film): Polish the platinum surface with toothpaste, rinse in distilled water, then soak in the KCL solution for 6 hours.

7 Recommended pH Electrodes for Specific Applications

The following table lists Apera pH electrodes recommended for use with the PH700 meter for various applications:

8 Warranty

APERA INSTRUMENTS (Europe) GmbH warrants this instrument to be free from defects in material and workmanship for a period of TWO YEARS (SIX MONTHS for the probe) from the delivery date. This warranty covers malfunctions or damage attributable to APERA INSTRUMENTS (Europe) GmbH. It does not cover damages due to transportation, storage, improper use, failure to follow instructions, unauthorized modifications, combination with unauthorized products, unauthorized repairs, normal wear and tear, or external causes beyond reasonable control.

APERA INSTRUMENTS (Europe) GmbH
Wilhelm-Muthmann-Straße 18, 42329 Wuppertal, Germany
Email: info@aperainst.de | www.aperainst.de | Tel. +49 202 51988998