Key Difference – HPLC vs HPTLC
The key difference between HPLC and HPTLC is that HPLC allows quantitative separation of components in a sample whereas HPTLC does not allow quantitative separation of components in a sample.
Chromatography is a physical separation method that is used to separate and identify the components in a mixture. Both HPLC and HPTLC are chromatographic techniques. HPLC is high performance liquid chromatography. HPTLC is high performance thin layer chromatography.
CONTENTS
1. Overview and Key Difference
2. What is HPLC
3. What is HPTLC
4. Side by Side Comparison – HPLC vs HPTLC in Tabular Form
5. Summary
What is HPLC?
HPLC is high-performance liquid chromatography. It is an analytical technique used to separate, identify and quantify components in a mixture. In this technique, the sample is dissolved in a suitable solvent. Then the solvent with the sample is passed through a pump with a given pressure. The pump is filled with solid adsorbent material. Then some components bind strongly to the absorbent material whereas other components bind loosely. This causes the components to have different flow rates through the pump. Therefore, the components can be separated easily.
Figure 01: A HPLC System
The adsorbent material that fills the pump is known as the stationary phase. The solvent with the dissolved sample is known as the mobile phase. The pump used in this technique is called the column. The column is filled with an adsorbent material, most commonly, silica particles. The size of these particles may range from 2-50 μm. The separation process is affected by the composition of the mobile phase and the temperature of the system. The interactions between the stationary phase and the component in the sample can be hydrophobic interactions, dipole-dipole interactions, ionic bonding, etc.
The operation pressure of the HPLC is considerably higher than that of the traditional liquid chromatography. It lies around 50-350 bar. The difference between liquid chromatography and HPLC is that in liquid chromatography, the sample falls through the column under gravity whereas, in HPLC, the sample is pressurized through the column. The size of the column and the absorbent particles are also very small when compared to the traditional liquid chromatography. However, the resolution given by the HPLC technique is superior.
What is HPTLC?
HPTLC is high performance thin layer chromatography. It is the advanced and automated form of traditional TLC. This technique provides an efficient resolution at a short time period. In this method of analysis, the sample and a reference can be analyzed at the same time, which allows the sample to be compared with the reference. It gives an improved analytical accuracy than other chromatographic techniques. The time taken for the analysis is less. The technique is a low-cost technique.
Figure 02: An Analysis of Food Dyes using HPTLC
The HPTLC method is a simple process, and the sample preparation step is also eliminated (In traditional TLC, the sample preparation step is included prior to the separation. This step involves cleaning and enrichment). The solvent can be used directly without any pre-treatment although other chromatographic techniques require pre-treatments such as degassing, filtration, etc.
The adsorbent material used in HPTLC is silica with very small particle sizes. In traditional TLC, the particle size of silica is 5-20 μm whereas, in HPTLC, it is 4-8 μm. The sample is applied to the HPTLC plate using an applicator. It gives a uniform and safe application. Then the plates are placed in a chamber having the mobile phase. The chamber should be saturated with the vapor of the mobile phase. After the HPTLC process, the spots that have moved can be detected. When detecting the spots on the plate, HPTLC technique uses a suitable UV region or an iodine chamber.
What is the Difference Between HPLC and HPTLC?
HPLC vs HPTLC |
|
| HPLC is high performance liquid chromatography. | HPTLC is high performance thin layer chromatography. |
| Technique | |
| In HPLC, the mobile phase with the solvent is passed through a column filled with the stationary phase. | In HPTLC, the sample is spotted on a TLC plate and is placed inside a chamber containing the mobile phase; then the sample is allowed to migrate upward the plate along with the mobile phase. |
| Measurement | |
| In HPLC, the differences between flow rates of components through the column is used to separate the components in the sample. | In HPTLC, the differences between distances traveled by each component in the sample is used to separate the components in the sample. |
| Quantitative Separation | |
| HPLC allows quantitative separation of components in a sample. | HPTLC does not allow quantitative separation of components in a sample. |
Summary – HPLC vs HPTLC
HPLC and HPTLC are two chromatographic techniques. The key difference between HPLC and HPTLC is that HPLC allows quantitative separation of components in a sample whereas HPTLC does not allow quantitative separation of components in a sample.
Reference:
1. “High-Performance Liquid Chromatography.” Wikipedia, Wikimedia Foundation, 10 Apr. 2018, Available here.
2. “HPTLC.” LinkedIn SlideShare, 30 May 2011, Available here.
Image Courtesy:
1. “HPTLCplatetoMS” By Kjaergaard at English Wikipedia – Transferred from en.wikipedia to Commons (Public Domain) via Commons Wikimedia
2. “Hplc”By PD Dr. rer. nat. habil. Gertrud MorlockAssociate Professor (Privatdozentin) University of HohenheimInstitute of Food Chemistry – G. Morlock, C. Oellig, CAMAG Bibliography Service 103 (2009) via Commons Wikimedia