Anton Paar offers Abbemat refractometers to provide simple, high-precision measurements of NaOH.
Sodium hydroxide (NaOH, also known as lye or caustic soda), is a staple of the chemical industry with applications ranging from the food and beverage industry to petroleum, and nearly everything in between.
The production of downstream products such as solvents, plastics, fabrics, adhesives, herbicides, dyes, inks and pharmaceuticals also requires NaOH.
Such production requires the determination of NaOH concentration for product consistency - traditionally achieved through titration.
However, the process is time-consuming, labour-intensive, and imprecise. In addition, NaOH has the tendency to absorb both water and carbon dioxide from the air, meaning that the the longer the measuring process, the more the NaOH solution will be affected and the more the accuracy of the measurement will be reduced.
Rapid and precise measurement of NaOH concentration can be achieved using refractometry.
Refractometers are used to measure the refractive index of a sample, a value that will remain constant between formulations with identical concentrations of ingredients.
Abbemat refractometers from Anton Paar are designed to provide accurate internal temperature control systems and automatic operation. The devices are capable of providing the kind of rapid, serial quality checks that are required on an assembly line.
The refractometers use an LED light source, which sends a beam of single-wavelength light through a measuring prism in contact with a sample at a controlled temperature.
Depending on the difference of the refractive indices between the NaOH solution and prism, the light is partly refracted and reflected, or totally reflected. The critical angle of total reflection is determined by measuring the reflected light intensity on a CCD array as a function of the incident angle.
Specially designed accessories for NaOH measurements are also available according to the application.
For simple measurement of low-concentrated solutions, a few drops can be placed directly in the optional Hastelloy B3 sample well.
If automation or the measurement of many samples is required, special micro flow cells, made of perfluoroalkoxy alkanes (PFA), are ideal for the measurement because of their high material resistance.
Using this setup, serial quality control checks can be performed without ever having to come into contact with the sample during measurement.