BI-870 dielectric constant meter for determining the HLB value of surfactants for an oil in water emulsion

BI-870 dielectric constant meter
BI-870 is a dielectric constant meter for the measurement of permittivity of low conductivity liquids such as cannabinoid oil, extracts, and surfactants used in preparing a nanoemulsion. The BI-870 uses an immersion probe made from two precision concentric cylinders which can measure dielectric constants in two ranges, from 1-20 and 1-200.
- Low- and high- range options
- Precision AISI 316 stainless steel sensors that are easily cleaned
- Simple operation for fast and repeatable measurements

Application Importance
Nonionic surfactants can be classified by their hydrophilic lipophilic balance (HLB).
For example, coconut oil and olive oil have a dielectric constant of 3.251. Oils that have a low DEC are lipophilic and will need surfactants with a high HLB value in order to work as an emulsifier.
The value is calculated by taking the mass of the hydrophilic portion divided by the mass of the whole molecule and multiplying by 20.
Values greater than 10 will be more hydrophilic while values less than 10 will be more lipophilic. The HLB value of a surfactant is linearly related to the log of the dielectric constant2.
The HLB of Tween 80 is 15.0 and has a dielectric constant value of 8.75 while the HLB for Span 80 is 4.3 and has a dielectric constant of 4.16.
The HLB value is important in understanding the effect that the surfactants will have on producing a nanoemulsion.
For cannabinoid and carrier oil the substance is lipophilic and, like all oils, will have a low dielectric constant.
For example, coconut oil and olive oil have a dielectric constant of 3.251. Oils that have a low DEC are lipophilic and will need surfactants with a high HLB value in order to work as an emulsifier.
For example, pine oil has a DEC of 4.67 and it is reported that a HLB of 13 is required to make an oil in water (o/w) emulsion2.
Mixed surfactant systems can be prepared by combining nonionic surfactants with known HLB values in controlled ratios to make a mixture with a desired HLB value.
Gorman and Hall demonstrated the relationship between the weight percent of Tween in Span to the log of the DEC and the approximate equivalent HLB value2. They concluded “the DEC of surfactant required for producing an o/w emulsion of any oil can be approximated from the graph by determining the DEC of the oil”.
The BI-870 is an ideal choice to quantify the dielectric constant of cannabinoids oils, extracts, and select nonionic surfactants for the optimization of a cannabinoid nanoemulsion.
How is Dielectric Constant Measured?
The dielectric constant is a measure of the ability of an insulator to store electric energy. It is determined by applying a stable voltage at a specific frequency to a probe made of two concentric cylinders.
The conductivity of the liquid is compensated by an 180o phase shift of a reference signal. Once the conductive current is compensated then it is possible to measure the capacitive current. The measurement is performed by placing the probe into a glass cylinder, which is then filled with enough liquid to cover the immersion probe.
A coarse and fine adjustment knob are then utilized to dial in to a final value., These fine adjustments are used to compensate for the conductivity component of the solution. The DEC can then be determined and the result is displayed on the LED display. This can be used quite effectively for oils, and other nonpolar liquids with very low conductivity.
HLB Values
< 10 : Lipid-soluble (water-insoluble)
> 10 : Water-soluble (lipid-insoluble)
3 to 6: W/O (water in oil) emulsifier
8 to 16: O/W (oil in water) emulsifier
BI-870 Dielectric Constant Probe
BI-870 Dielectric Constant Probe
- Made from two precision cylinders with a known cell constant
- Factory Calibrated
- Cylinders made from 316SS
- PTFE spacers used to maintain distance between cylinders
PTFE insulated coaxial cable.
BI-870 Specifications:
Dielectric Constant Range…………………1-20; 1-200 Dielectric Constant Resolution………… Dielectric Constant Accuracy……………2% Absolute: Repeatability and Linearity 0.2% Calibration…………………………………..Back Panel Adjustment with Reference Liquid Measurement Signal………………………Low-distortion, 10 kHz sine wave Maximum Conductivity of Sample……..Range 1-20: 1 µS/cm Range 1-200: 10 µS/cm (<0.05 mM 1:1 electrolyte) Operating Temperature……………………22° – 58°C Minimum Liquid Required………………. ~23 mL standard probe Display………………………………………Backlit LED Output……………………………………….Analog Recorder, Full Scale Reading 1.999 volts Probe Materials………………………….…AISI 316 Stainless Steel, PTFE Power Requirements……………………..100/115 and 220/240 VAC; 50/60 Hz; 10 Watts Dimensions…………………………………190 mm x 240 mm x 70 mm Ordering information: BI-870 is supplied with meter, probe, sample vials, power adapter, and instruction manual. References: |
References
1. Paranjpe, G. R.; Deshpande, P. V., Dielectric Properties of Some Vegetable Oils Indian Academy of Sciences 1935, 880-886 2. Gorman, W. G.; Hall, G. D., Use of Dielectric Constant in the Classification of Surfactants Journal of Pharmaceutical Sciences 1963, 52, (5), 442- 446 |
-
Measurement of Cannabinoid Nanoemulsion Droplet Size by Dynamic Light Scattering (DLS)
-
Measurement of Cannabinoid Nanoemulsion Stability with Zeta Potential
-
Contact
Our knowledgeable and dedicated professionals are standing by to assist you with your particle characterization challenges. For Sales or Support, fill out the appropriate form below and we’ll respond within 1 business day.