In a vacuum, light travels at 300.000 km/s while travelling through water, the speed is about 225.000 km/s,
which is 25 % less. In a sapphire it will only reach 170.000 km/s.
A refractometer is a measuring instrument for the speed of light. The result will not be indicated directly but related to the speed of light in air. This comparison is called refractive index. The indication, that a certain material has a refractive index of 1.5 thus means, that the speed of light travels 50 % faster through air than through this material.
Who is interested in the speed of light in samples?
The refractive index is a value specific to a material. It depends on temperature and wavelength (colour) of the light. Thus using a refractometer, will enable you to determine the concentration of a material, if temperature and wavelength are known. But it is also possible, that different materials have the same refractive index at various concentrations. Thus a clear determination of liquid substances may only be successful with binary mixtures (Mixtures consisting of two compounds).
In practice, the refractive index determines the mixing ratio also of multicompound solutions quite exactly and easily as in general only the concentration of one of the componends needs to be determined. Thus it is a quantitative measurement. With known compounds, also quality may be determined. For mixtures like for example olive oil or orange juice, the measuring value within a certain range corresponds to a certain quality.
Thus refractometry is a quality control of substances.
There is a definite correlation between the refractive index and the composition of many two-compound solutions. The best known example for such a mixture is a solution of sucrose in water, which has been studied throughly. A refractometer can be grated in a way that the value may be indicated directly as dry substance % RTS. For sucrose, this unit is also named Brix (abb. Bx).
The determination of the density of samples can also be done with refractometry. As a rule in optical measuments density and dry substance corresponds to each other.
Refractometers convert the measured refractive indices in concentration or density.
Laboratory refractometer with integrated Peltier-Thermostat The ATR-B Touch series with integrated Peltier-Thermostat gives you the possibility to work between 5 and 80°C. It has extremely low noise with a LED light source. It stays highly accurate and provides excellent reproducible measurements. The electronic unit is separated from the measuring head and can be placed horizontal or vertical, with the possibility to use the system as a flow-through instrument. The operation system is displayed on a broad 7” TFT touchscreen with integrated storage for your test results. The integrated software of ATR-B Touch allows you to personalize the display and data output of your results. It has an export interface to MS Excel, to txt and pdf-file and is easy to integrate to other LIMS systems. You can quickly set-up user-specific measurement scales with password protection for administrators and/or user profiles. ATR-B Touch: measuring range: 1.29000 - 1.58000 RI/100% Brix
• Dry substance
• Mass %
• Standard scales with automatic temperature compensation
• Quantitative analysis of dissolved solids in water or other solvents
Laboratory refractometer with integrated Peltier-Thermostat
The ATR-F Touch has an integrated Peltier Thermostat that gives you the possibility to work between +5°C and 100°C. The ATR-F Touch has a measuring range from 1.32000 to 1.7000 refractive index, with a resolution for this range of 0,00001 RI or 0,01% brix! With a precision of 0,00002 RI this instrument will meet all of your expectations. ATR-F Touch Full ABBE measuring range 1.32000 – 1.7000 RI/100% Brix with better resolution. Standard methods according to ASTM 1218, 1747 and others .
The SUGAR Refractometer
The critical angle refractometer ATR-P is especially designed for applications in the sugar industry. The complete system consists of the PURE-S measuring head and the "L-Display" electronic unit. As an alternative to the "L-Display" electronic unit, the PURE-S measuring head can be connected to a PC or laptop. In the minimal version configuration and calibration are performed using a supplied basic-software.
The basic model for standard applications is the ATR-C Economic model from Schmidt & Haensch. It has a robust and modern enclosure for rough environments. It has everything that is needed to produce highly accurate and reproducible measuring results in no time with an extreme low noise level at the detector side. The cleaning and handling procedure are very easy and the system could be calibrated with sucrose solutions or certified Chemical Reference Materials (CRM). Documentation according to GLP/GMP, 21 CFR part 11 are delivered with the instrument. The Energy saving LED light source can burn up to 100.000 hours without replacement.
Compact laboratory refractometer which is perfectly suitable for aggressive solutions and measurement of solids.
The new ATR-BR is a critical angle refractometer for the measuring of liquid media from low to high viscosity
and independent of opacity and color. The ATR instruments are available in a variety of configurations for
laboratory and production quality control.
The newly designed casing offers more space for a bigger LCD display and a splash proofed foil keyboard. Batch numbers can be entered directly and also a simple form may be created and printed out.
Four special scales, one of them being programmed as Brix scale by the factory, allow various applications in production and laboratory. All functions may also be controlled via PC using the remote control program.
Features of ATR Automatic Refractometers:
Refractometer with integrated Peltier-Thermostat, working t° up to 80 °C.
This SCHMIDT + HAENSCH automatic microprocessor controlled critical angle refractometer is designed to measure refractive index of liquid media independent of opacity, viscosity and color. It consists of separate electronic and measuring devices. A sample volume of 0.3 ml is sufficient for measuring. The sample is simply and easily placed by dropper or pouring onto the Peltier-thermostable sapphire prism. The prism is illuminated by long life yellow LED and the angle of totalreflection is detected by diode array which guarantees high resolution and stability.
The ATR-W1 enables to complete measurements in a quick and simple way by using splash proofed touch-in panel. Its new housing for the electronic offers more space for a bigger LCD display and an alphanumeric foil keypad. Batch numbers can be entered directly and also simple forms can be created and printed out. The % Brix is temperature corrected within +10 to +50 °C.
In the ATR-W series are four difference models, they have different parameters for the measuring ranges, the resolution and the precision. Please see table “Specifications“.
The digital, fully automatic spectral refractometer ATR-L consists of an electronic unit separated from the stainless steel measuring unit. Dispersion measurement at 7 wavelengths over the full visible range. A sample volume of 0,3 ml is sufficient for measuring. The refractometer is equipped with a Peltier thermostat (no external water bath/thermostat necessary).
Because the modern light sources like LED`s are offering highly directed light of a variety of wavelengths and are simple in use, it was possible to develop a robust multi-wavelength automatic refractometer, allowing to perform simple measurements of dispersion. The use of discrete LEDs also makes it possible to implement any combination of customer-specified wavelengths in the instrument and carry out quasi-spectral measurements in almost real time.
The digital multiple wavelength refractometer of SCHMIDT + HAENSCH is based on CCD-sensor detection of the critical angle of total reflection. This is done sequentially for all LEDs (colors) and displayed as refractive indices according to these wavelengths.
Potential applications will be found in research and development, where the exact knowledge of material properties is of great importance. Further fields of application will also be in the medical research (plastic lenses, contact lenses) and in communication technology (polymer materials, special optical liquids and glues).
The exact knowledge of material properties is of great importance for successful research and development. DSR-L can be used for example in medical development (plastic lenses, proteins …) and in the optical communication technology (polymer materials, special optical liquids, glasses and glues). In the petrochemical industry ATR-L can perform valuable services in scientific research and standard ASTM measurements.
The measurement principle of ATR-L relies on a complete refractive index measurement at visible wavelengths, which is also sensitive to absorption, leading to a full optical characterization of the measured substance. For example measuring a fruit juice will not only determine the sugar content but also provide valuable information on color and turbidity.
The measuring principle of the ATR-L is similar to DNA analysis giving unique fingerprint-like data for a particular product. Using this fingerprinting characterization, high quality products like wine, perfumes, alcoholic beverages etc. can easily be identified along with possible forgeries.
Digital handheld refractometer for directly display the measured values in terms of dry matter.
Two models (measuring ranges) are available.
Measurement of liquid media from low to high viscosity. Handy design, simple operation, reliable, automatic temperature compensated brix value within +10 to 70 °C.
Features of the DHR-B
Handheld refractometers are classic, visual refractometers and are used for the determination of the refractive
index of liquid media of low or high viscosity. They are mainly used for quick on-the-spot-control of process streams
and the field analysis in fruit and vegetable plantations.
Different models of handheld refractometers for special application available.
The Schmidt+Haensch ABBE refractometer AR12 is a classical, visual refractometer, named after its inventor Ernst Abbé and designed for the determination of the refractive index of liquid media with high or low viscosity. It is used in the fast control of liquids and the "in-field analysis".
The ABBE refractometer AR12 is equipped with hose connections at the prism unit for the thermostatisation of the optical parts. The temperature is measured with a digital thermometer. The measuring principle is based on the law of Snellius (law of refractive index) and is able to measure with transmitted or totally reflected light. With a contact fluid even solids can be measured with the ABBE refractometer.
Optional an illumination unit is available for prism and scale illumination with a red LED.
Digital thermometer (AR12)
ATR sample room cover
Stainless steel sample cover for single measurements with Schmidt +Haensch refractometers of the ATR series
ATR flow through compartment door
Stainless steel flow through compartment door (sample room volume approx. 80 μl) for laboratory refractometers of the ATR series from SCHMIDT + HAENSCH.
Certified Reference Material for refractometers
Certified reference material (CRM): 10 ml paraffin oil, refractive index ca. 1.467 (accuracy:10-4) for refractometer
Sugar reference solution, different concentrations, separate containers for saccharose and distilled water, after shuffle one week durable (concentration: 0 - 55 Bx)
Sugar reference solution, different concentrations, separate containers for saccharose and distilled water, after shuffle one week durable (concentration: 0 - 55 Bx), with factory certificate
10 ml standard reference solution with factory certificate, customer specified refractive index in the range 1.4 - 1.7,calibrated to 5 x 10-5 accuracy
10 ml paraffin oil with PTB certificate, refractive index 1.479. RI (accuracy 1 x 10-5)
10 ml silicone oil with PTB certificate, refractive index 1.403.. RI (accuracy 1 x 10-5)
10 ml paraffin oil with factory certificate, refractive index approx. 1.479.. RI (accuracy: 5 x10-5)
10 ml silicone oil with factory certificate, refractive index approx. 1,403.. RI (accuracy: 5 x10-5)
10 ml monobromo nahpthalen with factory certificate, refractive index approx. 1,655. RI (accuracy: 5 x10-5) (for ATR-F only)
10 ml technical white oil with factory certificate, refractive index approx. 1,473.. RI (accuracy: 5 x10-5)
10 ml Cyclohexane (RI 1.42662) pur, without certificate
10 ml monobromo naphtalin, index matching fluid, without certificate
Index matching (Diiodomethane) oil with certificate, 10 ml