Digital pH Measuring Meter
Pen-type digital pH meter with 0.01 pH resolution, ±0.05 pH accuracy, waterproof design, and automatic temperature compensation for portable field and laboratory measurements.
Louise Corscadden, PhD
Neuroscience · ConductScience
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The Digital pH Measuring Meter PH-98108 is a pen-type pH measurement instrument designed for portable field and laboratory applications. This waterproof unit features a large LCD display with automatic temperature compensation (ATC) and provides pH measurements across the full 0.00-14.00 pH range with 0.01 pH resolution and ±0.05 pH accuracy. The instrument operates on standard AG13 watch batteries and includes automatic shutdown after 4 minutes to conserve power.
The meter employs manual 2-point calibration for measurement accuracy and functions reliably in temperatures from 0-60°C with relative humidity up to 95%. At 90g and measuring 175×41×23mm, the unit provides laboratory-grade pH measurement capability in a compact, field-portable form factor suitable for diverse research and monitoring applications.
How It Works
The pH meter operates using a glass electrode system that generates a voltage proportional to hydrogen ion activity in the test solution. The glass membrane develops an electrochemical potential difference when exposed to solutions of different pH values, following the Nernst equation relationship where voltage changes approximately 59.16 mV per pH unit at 25°C.
The instrument's automatic temperature compensation (ATC) feature adjusts readings based on solution temperature, accounting for the temperature dependence of the Nernst slope. This ensures accurate pH measurements across the 0-60°C operating range without manual temperature corrections.
Manual 2-point calibration using standard buffer solutions (typically pH 4.01 and 7.00, or pH 7.00 and 10.01) establishes the electrode response curve and corrects for electrode aging and drift, maintaining the stated ±0.05 pH accuracy specification.
Features & Benefits
Measuring range
- 0.00~14.00pH
Research Domain
- Analytical Chemistry
- Environmental Monitoring
- Food Science
- Industrial Hygiene
- Microbiology
- Pharmaceutical QC
Model
- PH-98108
Calibration
- Manual, 2point
Working temperature
- 0~60°C, RHâ¤95%
Auto shut-off
- Approx. 4minutes
Automation Level
- manual
Brand
- ConductScience
Accuracy
- ±0.05pH
Power/Voltage
- 4x1.5V (AG13 Watch battery)
Dimensions
- 175Ã41Ã23mm
Weight
- 90g
Weight
- 0.09 kg
Dimensions
- L: 6.89 mm
- W: 1.61 mm
- H: 0.91 mm
| Feature | This Product | Typical Alternative | Advantage |
|---|---|---|---|
| Measurement Accuracy | ±0.05 pH | Entry-level models often provide ±0.1-0.2 pH accuracy | Higher accuracy reduces measurement uncertainty in quality control and research applications. |
| Resolution | 0.01 pH | Basic units may offer 0.1 pH resolution | Finer resolution enables detection of small pH changes in buffer optimization and process monitoring. |
| Calibration Method | Manual 2-point calibration | Single-point or no user calibration options | Two-point calibration corrects for both offset and slope errors, improving accuracy across the measurement range. |
| Temperature Compensation | Automatic Temperature Compensation (ATC) | Manual temperature correction required | ATC eliminates calculation steps and reduces user error in temperature-variable environments. |
| Operating Temperature Range | 0-60°C | Limited to room temperature operation | Extended temperature range supports field measurements and heated sample analysis. |
| Design Rating | Waterproof construction | Water-resistant or splash-proof only | Full waterproof rating enables use in wet field conditions and simplifies decontamination procedures. |
The PH-98108 combines analytical-grade accuracy and resolution with field-portable design, featuring automatic temperature compensation and waterproof construction. The manual 2-point calibration system provides measurement traceability while maintaining simplicity for routine use.
Practical Tips
Calibrate using buffers that bracket your expected measurement range for optimal accuracy.
Why: Calibration accuracy is highest within the buffer range used for calibration setup.
Allow buffer solutions to reach measurement temperature before calibration to minimize temperature-related errors.
Why: Temperature differences between calibration and measurement can introduce systematic errors despite ATC correction.
Rinse electrode with distilled water between samples and store in pH 4 buffer solution.
Why: Proper storage maintains electrode hydration and prevents contamination between measurements.
Replace batteries when LCD display becomes dim or readings become unstable.
Why: Low battery voltage affects analog-to-digital conversion accuracy and measurement stability.
Stir samples gently during measurement to ensure electrode equilibration with the bulk solution.
Why: Stirring eliminates local pH gradients and accelerates electrode response time.
Record both pH and temperature values for documentation of measurement conditions.
Why: Temperature affects chemical equilibria and provides context for pH measurement interpretation.
If readings drift or become sluggish, clean electrode with dilute HCl followed by distilled water rinse.
Why: Protein deposits and mineral buildup on the electrode surface reduce response speed and accuracy.
Verify accuracy periodically with a third buffer solution not used in the calibration procedure.
Why: Independent verification confirms calibration validity and detects electrode drift between calibrations.
Setup Guide
What’s in the Box
- PH-98108 Digital pH Meter
- 4 × AG13 watch batteries
- Protective electrode cap
- User manual and calibration instructions
- Calibration certificate (typical)
- Carrying case (typical)
Warranty
ConductScience provides a 1-year manufacturer warranty covering defects in materials and workmanship, with technical support for calibration and operational questions.
Compliance
What calibration frequency is recommended for maintaining accuracy?
Calibrate daily for critical measurements or weekly for routine work. Recalibrate if readings drift beyond ±0.1 pH when testing known buffer solutions.
Can this meter measure pH in samples containing organic solvents?
The glass electrode is designed for aqueous solutions. Organic solvents may damage the electrode or provide inaccurate readings. Consult product datasheet for specific solvent compatibility.
How does temperature affect measurement accuracy?
The ATC feature compensates for temperature effects on electrode response, but sample temperature should be within 0-60°C range for accurate compensation.
What is the expected electrode lifespan?
Electrode life varies with usage conditions and maintenance. Typical lifespan ranges from 6-24 months depending on sample types and storage conditions.
Is the meter suitable for continuous monitoring applications?
This is a portable spot-measurement device with 4-minute auto-shutdown. It is not designed for continuous monitoring or data logging applications.
What buffer solutions are recommended for calibration?
Use certified pH 4.01, 7.00, and 10.01 buffer solutions. Select two buffers that bracket your measurement range for optimal accuracy.
How should the electrode be stored between measurements?
Store with protective cap containing pH 4 buffer solution or electrode storage solution. Never store dry or in distilled water as this damages the glass membrane.
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