As a national innovation fund project, micro-electrophoresis meter (Zeta potential meter) developed and manufactured exclusively by Shanghai Powereach Digital Technology Equipment Co., Ltd has been available on the market for 24 years. The instrument can be used to measure the electrical property of solid-liquid interface of dispersed system particulate matter, electrical property of emulsion drop interface and isoelectric point, and to study mechanism in interface reaction process. To get the isoelectric points through measuring Zeta potential of particulate matter is both an important method for getting to know the electrical property of particulate matter, and a key measures in particulate matter surface treatment. It has significant advantages when compared with domestic and overseas similar types of instruments. It can be widely applied in cosmetic, mineral separation, papermaking, medical health, building material, ultra-fine material, environmental protection, marine chemistry and other industries and is a key teaching instrument for chemistry, chemical engineering, medicine, building material and other specialties.
The first national standard Analysis of Zeta Potential of Colloids-Electrophoresis Guidelines GB/T 32668-2016 was issued and implemented on November 1, 2016. The microelectrophoresis method of the standard is complied according to JS94 series of micro-electrophoresis meter (zeta potential meter) developed and manufactured exclusively by Shanghai Powereach Digital Technology Equipment Co., Ltd. The picture on page 16 of this standard is the software interface of JS94 series of micro-electrophoresis meter (zeta potential meter) manufactured by Shanghai Powereach .
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Main models of JS94 series of micro-electrophoresis meter(zeta potential meter) (Table 1) |
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Model |
Applicable system |
Main particle size range （μm） |
Microscopic CCD optical system |
Resolution |
Tax-inclusive price (CNY) |
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JS94H |
Aqueous system |
0.5~20 |
High power microscope optical system |
4pixel/μm |
50000+4000 |
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JS94H2 |
Aqueous system and organic system |
0.5~20 |
High power microscope optical system |
4pixel/μm |
61200+4000 |
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JS94J |
Aqueous system |
0.1~10 |
Japanese WKD High power microscope optical system |
12pixel/μm |
68200+4000 |
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JS94J2 |
Aqueous system and organic system |
0.1~10 |
Japanese WKD High power microscope optical system |
12pixel/μm |
79500+4000 |
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JS94K |
Aqueous system |
0.2~50 |
Japanese continuous zooming optical system, applicable to measurement of wider range of particle size |
8pixel/μm |
81800+4000 |
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JS94K2 |
Aqueous system and organic system |
0.2~50 |
Japanese continuous zooming optical system, applicable to measurement of wider range of particle size |
8pixel/μm |
94000+4000 |
Note 1: the price above is inclusive of dedicated supporting computer, instrument, experiment operation software, standard components, free home delivery, installation, debugging and training (door-to-door service fee will be charged for few individual remote regions), and one-year warranty service, free lifetime upgrade of software, tax-inclusive.
I. Standard configuration of JS94 series of micro-electrophoresis meter (Zeta potential meter)
1. USB system digital CCD 1
2. Silver electrode 1
3. Platinum electrode 1
4. POM electrode 1（for JS94H2, JS94J2 and JS94K2 only）
5. Electrophoresis cup 10
6. Cross 1
7. Application software and operation manual in electronic form 1 set
8. Operation manual in paper form 1 piece
9. A Data acquisition and processing of microcomputer operating terminal with pre-loaded application programs and drive program
II. Common parameters of JS94 series of micro-electrophoresis (Zeta potential meter)
1. Power consumption: <150W
2. Power input voltage: 220V 50Hz
3. Applicable environment: Shock-proof platform
4. Applicable temperature range: Room temperature to 35℃, reading precision: 0.1
5. Measurement accuracy: System error is within 5%
6. pH range: Generally used within the range of 2.0～12.0, also available within the range of 1.6～13.0.
7. Working distance: 7mm
8. Cup-type open electrophoresis device, equipped with special electrode holder
III. Features of JS94 series of micro-electrophoresis meter(Zeta potential meter)
1. The instrument adopts newly designed simple electrophoretic cell and 0.5cm thick glass cup with the electrode built-in the cell. The Electrophoresis cup and built-in electrode are subjected to precise microflow field calculation and surface treatment to form a set of electrophoresis device that is completely different with the electrophoretic cell. The test needs extremely little sample, 0.5ml for each time, and the meter is easy to clean and use and is economical and practical.
2. It uses a well-designed electrode holder which fits well with the Electrophoresis cup to form a cup-shaped open electrophoresis device. The electrode is made of silver, platinum and titanium metal wires and has a stable working state after surface treatment.
3. The cross exquisitely fabricated is embedded in electrophoresis cup and then placed on 3D platform. Cross image can be found clearly on computer screen to find out measuring position, thus avoiding stationary layer.
4. The electrophoresis meter adopts semiconductor light emitting near-field optical system with the power of only tens of microwatts, to avoid the impact on measurement environment and measurement precision caused by heating. Moreover, it adjusts the optical system, increases the amplification factor and uses blue light and green light with short wave length, to see smaller particulate matters clearly.
5. It adopts constant voltage low-frequency conversion power and thus prevents polarization and improves measurement speed greatly. Positive and negative reversal time is 0.30 to 1.20s, which is continuously adjustable, and the sampling time is 3～10s only. The inter-electrode voltage is adjustable as required.
6. It adopts temperature sampling probe for sampling environment temperature in a automatic and continuous way. The sampled data will be transmitted to the computer and parameters will be adjusted automatically to calculate Zeta potential. It uses computer multimedia technology, conducts continuous “shooting” of ultra-fine particulate matters magnified by 1200 times, and offers bi-directional four grayscale images for analysis and calculation.
IV. Advantages and disadvantages in zeta potential measurement using video method and laser diffraction method
Where the contrast of advantages and disadvantages in zeta potential measurement using video method and laser diffraction method is required, refer to Table 2 and Precision and Accuracy-Discussion on two Measurement Method Methods of Zeta Potential.
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Comparative table of domestic and oversea micro-electrophoresis (zeta potential meter) (table 2) |
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Zeta potential
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Shanghai Powereach JS94 series |
Imported micro-electrophoresis(adopts laser diffraction method in general) |
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Measurement method
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It adopts video measurement technology: “what you see is what you get” in entire analysis process, so the data is certainly accurate and is measured value and it is hard to make a mistake. |
It uses laser diffraction measurement technology generally. “According to ISO13320, if the particulate matter size is less than tens of micrometers, Mie Theory shall be used and correct sample refractive index and absorptivity shall be input to obtain more accurate results” Therefore, the calculated value of zeta potential measured by the kind of instrument can be obtained based on correct absorption rate and other parameters. |
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Measurement object
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It is the only instrument which can achieve the most accurate measured value of zeta potential. Restricted by its measurement method, charged particle shape and size can be observed one by one only and histogram of particle size distribution of the entire disperse system cannot be generated. |
It is the best instrument for measurement of histogram of particle size distribution of the entire disperse system, but its zeta potential measurement function is for reference only. |
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Scope of application
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It needs not to measure the particle size distribution of the entire system, so we can use partial charged particles not settled to represent zeta potential of charged particles in entire disperse system. Therefore, it will be acceptable if the measured sample contains some charged particles whose sizes are within 0.1~50 μm. |
“Where the particle size is less than several hundred nanometers, its diffraction intensity almost loses dependence on angle completely”. |
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Sample preparation
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The sample needs no pretreatment, and requires dilution only under extreme conditions (for example, thick and opaque sample). |
Many samples needs pretreatment conducted according to operation manual, measurement of their correct refractive index and absorptivity in advance, and input of them into operation software for obtaining calculated value of zeta potential. |
Note 2: blue words in aforesaid table are quoted from Technical Status and Selection of Laser Particle Analyzer, a monthly publication October 2009, Instrument Express.
