Index of refraction monitors, says Entegris, can control biopharmaceutical purification processes in the spirit of process analytical technology. Detection of liquid concentrations by optical means was already known in light is lower than this value, and the refractive index, R.I., of a medium is a The angle of refraction can be calculated by using the simple geometric relations (Fig. The theoretical equation you are looking for is actually referred to as a model, solute concentration of a liquid medium and its refractive index.
Filters are often placed downstream in order to capture any material that escapes the separation method. IoR can also identify buffers for diafiltration and recovery of product, while detecting even small concentrations of cells or cellular debris breakthrough. Due to this identification and detection, processes can be designed to bypass cellular breakthrough filters until, and only if, they are needed.
This can lead to a cost savings. During MF and depth filtration, IoR monitors optimize the diafiltration process by detecting when a product is below its target concentration. Utilizing real-time IoR monitors enhances these processes by reducing process time and product dilution.
Affinity Chromatography In many processes, affinity chromatography performs most of the product purification process. During cell removal, IoR monitors can identify each incoming buffer that prepares and equilibrates the cell removal system. Especially during affinity chromatography, an incorrect buffer can inadvertently damage the resin, causing thousands of dollars in lost material, before processing even begins.
Regarding inadequate resin concentration, IoR monitors detect product breakthroughs, channeling, or high asymmetry in the bed, potentially saving product loss. To optimize product peak detection during the collection process IoR monitors provide augmentation or replacement of ultraviolet-visible spectrophotometry UV-VIS technologies.
Additionally, IoR can determine the post-use removal completion of bound contaminants to ensure a faster and more optimized cleaning process.
As in affinity chromatography and other chromatography steps, IoR monitors can be used to positive identify all incoming buffers and product, as shown in Figure 2. Consequently, IoR can control when each peak is collected. Therefore, these monitors identify process fluids and control the entire process more notably than in other downstream processing steps.
IoR detection of product and buffers in chromatography. There are three distinct process points where positive fluid identification and product concentration knowledge will achieve more process control and faster overall process time.
During product concentration, the process operates until the product is at a target concentration, often verified by sampling and offline quality verification. These sampling and verification steps could be eliminated if IoR monitors are used as a real-time detection method. Next, during diafiltration and buffer exchange, IoR can verify the completed exchange step.
Finally, quality lab sampling and offline verification during the final concentration point would not be required using IoR measurements.
Concentration Measurement with Refractive Index
Various techniques have been developed to determine the contents of sugar in solutions [ 12 - 14 ]. The techniques are Inter digital Capacitor Sensor to determine the contents of sugar in solution [ 12 ]; optical Coherence Tomography to determine blood glucose concentration in diabetic patients [ 13 ]; Quantification of sugar in soft drinks and fruit juices by Density, refractometry, infrared spectroscopy and statistical methods [ 14 - 16 ] are some of the techniques so far developed.
The above mentioned techniques are industrial made instrument used to determine the concentration of sugar in solution. Such kind of instrument is very expensive and also not available in most laboratories. Materials and Methods Materials Locally constructed equilateral hollow prism, Red and Green Diode laser, He-Ne laser as light sources, digital electronic balance with a good accuracy for mass measurement were used.
In addition, different apparatus such as measuring cylinder to measure the volume of water, mercury thermometer to control the temperatures of the solutions and magnetic stirrer with hot plate for heating and mixing the solution. In addition, deionized water as solvent, locally produced sugar and soft drink beverages Pepsi, Coca, 7up, Sprite, Mirind and Fanta were used as our sample.
Concentration Measurement with Refractive Index
Calibration curve developed from the graph of refractive index versus the concentration of the solution. Numerical procedure of fitting the experimental data was carried out by linear curve fitting using origin 8 software.
A theory and method for derivation of refractive index have been discussed elsewhere [ 1 - 25 ]. The angle of incidence is responsible for deviation produced in the path of light beam.
A monochromatic source of light Red, Green Diode laser and He-Ne laser was allowed to fall at angle of incident on the face of the liquid prism and the angle of minimum deviation was determined for each laser light.
During the measurement the solutions were filtered before pouring into the hollow prism. The hollow prism was also rinsed carefully after every measurement. Each measurement has taken three times. Experimental set up for the measurements of angle of minimum deviation using prism spectrometer. Methods of measuring temperature dependent refractive The temperature dependent refractive indices of the solution measured at the temperatures The solutions were heated using magnetic stirrer with hot plate and its temperature controlled by placing the thermometer inside a solution.
The angle of minimum deviation was measured at the interval of 5 K while the solution is cooling down from highest to lowest temperature. Calibration curve developed from the graph of refractive index versus temperature of the solution.
Soft drink beverage solutions preparation In order to measure the sugar contents in soft drink beverages Pepsi, Coca, 7up, Sprite, Fanta and Mirinda each sample was poured into a beaker and stirred for minutes by magnetic stirrer to remove gases within the samples. The refractive index of each solution was calculated from angle of minimum deviation using Equation 1. The sugar contents in soft drink beverages were determined using eqns. From experimental data we can find that RI of sugar solution increase linearly with the concentration.