Differbetween
The key difference between rate theory and plate theory is that rate theory describes the properties of a chromatographic separation via comparing the rate of analyte that elutes through the column whereas plate theory describes the properties of chromatographic separation via determining the number of hypothetical ...
- What is rate theory?
- What is plate theory of chromatography?
- What is a theoretical plate and the relationship between separation efficiency?
- How do you find theoretical plates?
- What is a theoretical plate and why is it important?
- How do you calculate flow rate in HPLC?
- What is a good number of theoretical plates?
- What is column efficiency?
- What does the term theoretical plate mean?
- What is an ideal plate?
- How is Hetp calculated?
- What is the most common type of plate you have at home?
What is rate theory?
The Rate Theory of Chromatography• In the rate theory, a number of different peak dispersion processes were proposed and expressions were developed that described • the contribution of each of the processes to the total variance of the eluted peak • the final equation that gave an expression for the variance per unit ...
What is plate theory of chromatography?
Theoretical plates represent a hypothetical division of chromatographic columns, and each plate represents an equilibrated partitioning of the solute between the stationary and mobile phases.
What is a theoretical plate and the relationship between separation efficiency?
The number of theoretical plates is the number of discrete distillations that would have to be performed to obtain an equivalent separation. This number is commonly used as a measure of separation efficiency and is a useful number to use when comparing the performance of various chromatographic columns.
How do you find theoretical plates?
Should you need to calculate the number of theoretical plates per meter, you must use the following equation:
- Number of theoretical plates per column x 100/length of HPLC column (cm)= Number of theoretical Plates per m.
- Rss = (tr2 – tr1) / ((0.5 * (w1 + w2)
- Rs = (tR2 – tR1) / ((1.7 * 0.5 (w0.5,1 + w0.5,2))
What is a theoretical plate and why is it important?
Theoretical plate number (N) is an index that indicates column efficiency. It describes the number of plates as defined according to plate theory, and can be used to determine column efficiency based on calculation in which the larger the theoretical plate number the sharper the peaks.
How do you calculate flow rate in HPLC?
When going from a 4.6 to a 2.1mm ID or to any smaller ID column decrease the flow rate by the square of the ratios of the column diameters. As mentioned above the standard flow rate for a 4.6 mm column is 1 ml/min. In our example the new flow rate determined for the 2.1 mm column is 0.208 ml/min.
What is a good number of theoretical plates?
The number of theoretical plates is often used to establish the efficiency of a column. Plate numbers range from 100 to 106. The more theoretical plates available within a column, the more equilibrations between the stationary and mobile phases are possible and the better the quality of the separation.
What is column efficiency?
Column efficiency, also known as plate count, is a measure of the dispersion of a peak. Narrow peaks take up less space in the chromatogram and thus allow more peaks to be separated. ... A high value for efficiency indicates that more peaks can be separated. The number of plates will increase with the length of the column.
What does the term theoretical plate mean?
A theoretical plate in many separation processes is a hypothetical zone or stage in which two phases, such as the liquid and vapor phases of a substance, establish an equilibrium with each other. Such equilibrium stages may also be referred to as an equilibrium stage, ideal stage, or a theoretical tray.
What is an ideal plate?
An ideal plate is defined as one where. [A]. the vapour and liquid leaving streams are in equilibrium. [B]. the vapour and liquid entering streams are in equilibrium.
How is Hetp calculated?
HETP — in order to normalize N across columns of different sizes, divide the length of the column by N. This provides the height equivalent to theoretical plate (HETP) value. The lower your HETP the more efficient the separation. The HETP can be measured over time to monitor column performance.
What is the most common type of plate you have at home?
Ceramic. Ceramic plates are perhaps the most common type of plate that people use on a daily basis. These types of plates are incredibly useful and can be used for many years without any problem. Of course, ceramics are a very versatile type of plate as well.
