ZetaPotential analyzer is a core tool for evaluating the stability of colloidal systems, which measures the surface charge distribution of particles（ZetaPotential guidance for formula optimization and quality control in fields such as nanomaterials, pharmaceuticals, and food. This article focuses on typical electrophoretic light scattering（ELS）Taking the type of instrument as an example, systematically explain its usage method, covering the operation process, key parameter settings, and maintenance points.

1、 Preparation before operation: Environmental and sample requirements

1. environmental conditions

Temperature: The laboratory temperature needs to be controlled within the specified range of the instrument (usually5-40℃）To avoid temperature fluctuations affecting conductivity measurement.

Humidity: Relative humidity is recommended to be below80%To prevent moisture from affecting the sample pool or optical components.

Shock resistant: The instrument should be placed on a stable experimental platform to avoid vibration interference with laser scattering signals.

2. Sample preparation

Dilution and filtration: High concentration samples need to be diluted to an appropriate range (such as colloidal particle concentration)0.01-1% w/v）To avoid multiple scattering interference; Turbid samples need to pass through0.22μmMembrane filtration.

pHAdjustment: If research is neededpHtoZetaThe influence of potential needs to be controlled using buffer solution (such as phosphate buffer solution)pHValue, avoid direct addition of acid and alkali to prevent uneven local concentration.

Degassing treatment: Samples containing bubbles (such as protein solutions) require ultrasonic degassing5-10Minute, to prevent bubbles from interfering with the distribution of electric field.

2、 Operation steps: from startup to data analysis

step1: Instrument initialization and calibration

Power on self-test: After connecting the power, the instrument automatically detects the laser source, photodetector, and electric field module, and confirms that there are no error prompts (such as“Laser Error”or“Field Stability Fault”）.

Electric field calibration: using standard solutions (such as1mM KClPerform electric field strength calibration on a solution with known conductivity to ensure that the actual electric field deviates less than the set value2%.

Optical path calibration: operation“Optical Alignment”Program to adjust the position of the laser beam and detector to achieve maximum scattered light intensity.

step2Sample loading and parameter setting

Select sample pool: Choose the appropriate pool based on the sample type:

Conventional aqueous solution: Foldable capillary cell（Folded Capillary Cell）.

Organic solvents:UType quartz pool (equipped with anti volatilization cover).

Online monitoring: circulation pool（Flow Cell）Connect the peristaltic pump to achieve continuous injection.

Loading samples: Slowly inject samples into the pool using a pipette2/3Height, avoid generating bubbles; Organic solvent samples need to be pre wetted into the pool wall30In seconds.

Parameter settings:

Electric field strength: Adjust according to the conductivity of the sample (use high field strength for low conductivity samples, and lower field strength for low conductivity samples).

Temperature: Set the measurement temperature (such as25℃）The instrument automatically starts upPeltierTemperature control system.

Measurement frequency: It is recommended to repeat3-5Take the average value to improve data reliability.

step3: Data Collection and Processing

Start measurement: Click“Start”Button, the instrument applies an electric field and records the frequency change of scattered light, and calculates the electrophoresis rate through Doppler frequency shift.

Real time monitoring: observe whether the electrophoresis curve is stable, and if there is any fluctuation (such as curve jitter>5%）It is necessary to check the uniformity of the sample or the stability of the electric field.

Data analysis:

ZetaPotential calculation: The software automatically calculates based onSmoluchowskiModel (high conductivity solution) orHückelThe conversion electrophoresis rate of the model (low conductivity solution) isZetaPotential value.

Distribution statistics: GenerateZetaPotential distribution map, evaluate sample uniformity (such as multi-modal distribution indicating particle aggregation or uneven surface modification).

Report export: supportedPDFTheCSVFormat output, including measurement conditions, raw data, and statistical results.

3、 Key precautions: Avoid common errors

1. Electric field stability control

High conductivity solution (such as saltwater): electric field strength required≤100V/cmTo avoid Joule heating causing local temperature rise and affecting electrophoresis rate measurement.

Low conductivity solution (such as organic solvents): Platinum electrodes should be used and cleaned regularly to prevent electrode polarization from generating bubbles.

2. Sample uniformity guarantee

Magnetic stirring: Perform magnetic stirring on the sample before measurement (speed)200-500rpm）5Minutes, ensure that the particles are evenly dispersed.

Avoid settling: High density particle samples (such as metal oxides) need to be sonicated before measurement1Minutes to prevent data deviation caused by settlement.

3. Optical interference elimination

Environmental light shielding: Turn off laboratory lights and use the instrument's built-in light shield to prevent stray light from entering the detector.

Sample cell cleaning: Rinse the sample cell with ultrapure water after each measurement, wipe the optical window with isopropanol to prevent residual samples from interfering with subsequent measurements.

4、 Typical Problems and Solutions

problem1：ZetaPoor repeatability of potential values

Possible reasons: sample settling, electric field fluctuations, and unstable temperature.

Solution: Increase mixing time, reduce electric field strength, and check temperature control module.

problem2Weak scattered light signal

Possible reasons: low sample concentration, laser attenuation, and optical path deviation.

Solution: Increase the sample concentration and replace the laser lamp (usually with a longer lifespan)20000Hour by hour, recalibrate the optical path.

problem3Electric field cannot be applied

Possible reasons: poor electrode contact, sample conductivity exceeding the range.

Solution: Check electrode connections, dilute samples, or replace high conductivity specialized electrodes.

5、 Maintenance and upkeep: Extend the lifespan of the instrument

1. Daily cleaning

Optical components: Clean the laser window and detector lens with a dust-free cloth dipped in isopropanol every week.

Sample pool: Clean immediately after each use to avoid sample crystallization blocking the pool body.

2. periodic calibration

Electric field calibration: Verify the accuracy of electric field strength using standard solutions every month.

Temperature calibration: Calibrate quarterly with high-precision thermometersPeltiermodular.

3. Consumables replacement

Laser lamp: When the scattered light intensity drops to the initial value70%When necessary, the laser source needs to be replaced.

Electrode: When an oxide layer appears on the surface of a platinum electrode, polish it with fine sandpaper or replace it with a new electrode.

Conclusion

ZetaThe accurate measurement of a potential analyzer relies on standardized operating procedures and meticulous environmental control. By strictly following the steps of sample preparation, parameter setting, data collection, and maintenance, error sources can be effectively avoided and reliable results can be obtainedZetaPotential data. With the improvement of instrument automation, such as one click calibrationAIThe operational threshold for auxiliary analysis is gradually decreasing, but understanding the core principles and key considerations remains the foundation for ensuring data quality.