Hand pH Meter
Portable pen-type digital pH meter providing ±0.05 pH accuracy across 0.00-14.00 pH range with automatic temperature compensation and waterproof design for laboratory and field applications.
Louise Corscadden, PhD
Neuroscience · ConductScience
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The Hand pH Meter (Model PH-981) is a portable pen-type digital pH meter designed for precise pH measurements in laboratory and field applications. This instrument provides accurate pH measurements across the full pH scale (0.00-14.00) with ±0.05 pH accuracy and 0.01 pH resolution, making it suitable for routine water quality testing, environmental monitoring, and laboratory protocols requiring reliable pH determination.
The meter features automatic temperature compensation (ATC), data hold functionality, and a backlit display for enhanced usability in varied lighting conditions. With waterproof construction and compact pen-style design (168×37×20mm, 65g), the instrument enables direct immersion measurements in aqueous samples while maintaining portability for field work. The one-point calibration system simplifies routine maintenance while the 4-minute auto shut-off conserves battery life during extended use.
How It Works
The pH meter operates using potentiometric measurement principles, employing a glass electrode sensitive to hydrogen ion activity in aqueous solutions. The electrode generates a voltage proportional to the logarithm of hydrogen ion concentration, which the instrument converts to pH units through internal calibration algorithms. The glass membrane selectively responds to H+ ions, creating a potential difference across the electrode that correlates directly with solution pH.
Automatic temperature compensation adjusts readings based on solution temperature, accounting for the temperature dependence of electrode response and solution pH. The digital processing unit amplifies the electrode signal, applies temperature correction factors, and displays the corrected pH value on the backlit LCD. The waterproof construction allows direct immersion of the electrode tip while protecting internal electronics from moisture exposure.
Features & Benefits
Measuring range
- 0.00~14.00pH
Research Domain
- Analytical Chemistry
- Food Science
- Industrial Hygiene
- Microbiology
- Pharmaceutical QC
- Water Quality & Environmental Monitoring
Calibration
- 1point
Feature
- Backlit screen;Data hold function
Model
- PH-981
Working temperature
- 0~60°C, Râ¤H95%
Auto shut-off
- Approx. 4 minutes
Automation Level
- manual
Brand
- ConductScience
Accuracy
- ±0.05pH
Power/Voltage
- 4Ã1.5v alkaline
Dimensions
- 168Ã33Ã20mm
Weight
- 65g
Weight
- 0.07 kg
Dimensions
- L: 6.61 mm
- W: 1.46 mm
- H: 0.79 mm
| Feature | This Product | Typical Alternative | Advantage |
|---|---|---|---|
| pH Measurement Range | 0.00-14.00 pH (full scale) | Many entry-level meters offer limited ranges or reduced accuracy at pH extremes | Full pH scale capability accommodates highly acidic and alkaline samples without range limitations. |
| Measurement Accuracy | ±0.05 pH | Basic meters often provide ±0.1 or ±0.2 pH accuracy | Higher precision supports analytical chemistry applications requiring reliable quantitative results. |
| Temperature Compensation | Automatic temperature compensation (ATC) | Manual temperature adjustment or no compensation | Eliminates user error and improves measurement reliability across varying sample temperatures. |
| Display Resolution | 0.01 pH resolution | Lower-cost models may offer 0.1 pH resolution | Finer resolution enables detection of small pH changes important in process monitoring and quality control. |
| Environmental Protection | Waterproof construction | Many portable meters lack waterproof ratings | Direct sample immersion capability reduces contamination risk and enables field measurements in wet conditions. |
| Power Management | 4-minute auto shut-off | Manual power control or shorter auto-off times | Balances battery conservation with measurement workflow convenience for extended field use. |
The PH-981 combines analytical-grade accuracy (±0.05 pH) with field-portable design and waterproof construction. The automatic temperature compensation and backlit display enhance usability while the pen-style form factor provides exceptional portability for field applications.
Practical Tips
Store calibration buffer solutions in sealed containers and replace monthly to maintain accuracy.
Why: Buffer degradation and contamination directly impact calibration precision and measurement reliability.
Rinse the electrode with distilled water between samples and store with the protective cap in place.
Why: Prevents cross-contamination and electrode surface contamination that can cause drift and sluggish response.
Allow the electrode to equilibrate in sample for 30-60 seconds before recording readings.
Why: Electrode response time varies with sample composition and temperature, affecting measurement stability.
If readings drift or respond slowly, soak the electrode tip in pH 7 buffer for several minutes.
Why: Electrode surface conditioning can restore response time and stability after exposure to extreme pH or contaminating samples.
Record sample temperature alongside pH measurements for documentation and trend analysis.
Why: Temperature affects solution pH independent of electrode compensation, providing important analytical context.
Avoid measuring pH in samples containing hydrofluoric acid or strong organic solvents.
Why: These chemicals can permanently damage the glass electrode membrane and compromise measurement accuracy.
Verify calibration with a second buffer (pH 4.0 or 10.0) periodically to check electrode slope.
Why: Electrode aging affects response slope, and two-point verification helps identify when electrode replacement is needed.
Replace batteries when the display becomes dim or readings become unstable.
Why: Low battery voltage affects amplifier stability and can cause measurement errors or display irregularities.
Setup Guide
What’s in the Box
- Hand pH Meter (Model PH-981)
- Protective electrode cap
- User manual with calibration procedures
- Four 1.5V alkaline batteries (typical)
- Calibration buffer solutions (typical)
- Carrying case (typical)
Warranty
ConductScience provides a standard one-year manufacturer warranty covering defects in materials and workmanship, with technical support for calibration procedures and troubleshooting assistance.
Compliance
References
Background reading relevant to this product:
What calibration frequency is recommended for maintaining ±0.05 pH accuracy?
One-point calibration with pH 7.0 buffer should be performed daily for routine use, or before each measurement session when maximum accuracy is required. Consult product datasheet for specific calibration stability data.
Can this meter measure pH in non-aqueous or high-ionic-strength solutions?
The glass electrode is optimized for aqueous solutions. Non-aqueous solvents or high ionic strength matrices may affect accuracy. Consult manufacturer specifications for specific solution compatibility limits.
How does temperature compensation work across the 0-60°C operating range?
Automatic temperature compensation applies standard temperature correction algorithms to adjust for electrode slope and solution pH temperature dependence. Accuracy specifications apply across the full operating temperature range.
What is the typical electrode lifespan under normal laboratory use?
Electrode lifetime varies with sample types and storage conditions. Proper maintenance with appropriate storage solutions and regular calibration typically provides 6-12 months of reliable service.
Does the data hold function store readings for later download?
The data hold feature temporarily freezes the display for manual recording. This meter does not include data logging or computer connectivity features for automated data transfer.
How does this pen-style meter compare to benchtop pH meters for accuracy?
The ±0.05 pH accuracy is suitable for most routine applications but may be less precise than research-grade benchtop meters with ±0.01 pH specifications. The trade-off provides portability and field measurement capability.
What maintenance is required for the waterproof construction?
Rinse the electrode after each use and ensure the protective cap is properly sealed. Avoid exposing connection points to moisture and check O-ring seals periodically for wear or damage.
Can the meter be used for continuous monitoring applications?
The 4-minute auto shut-off and manual operation design make this meter suitable for spot measurements rather than continuous monitoring. Consider dedicated process pH controllers for continuous applications.
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