What is the Difference Between HPLC and HPTLC

The main difference between HPLC and HPTLC is that HPLC is the enhanced form of liquid chromatography, whereas HPTLC is the enhanced form of thin-layer chromatography. 

HPLC and HPTLC are two types of automated separation techniques with similar principles of separation. Furthermore, HPLC consists of a pump-driven flow system through the stationary phase filled in a column while HPTLC is a type of planar chromatography in which the solvent moves through a stationary phase fixed on a plate. Moreover, HPLC consists of a closed system, while HPTLC is an open system. 

Key Areas Covered 

1. What is HPLC
     – Definition, Features, Importance
2. What is HPTLC
     – Definition, Features, Importance
3. What are the Similarities Between HPLC and HPTLC
     – Outline of Common Features
4. What is the Difference Between HPLC and HPTLC
     – Comparison of Key Differences

Key Terms

Column Chromatography, HPLC, HPTLC, Separation Plate, TLC

What is HPLC 

HPLC (high-pressure liquid chromatography or high-performance liquid chromatography) is an enhanced form of liquid chromatography. Therefore, it is a type of column chromatography, which involves the high-pressure pumping of a mixture dissolved in the liquid mobile phase through a column filled with the solid stationary phase. Moreover, a carrier gas such as helium or nitrogen is responsible for the movement of the sample through the column. 

Figure 1: HPLC Chromatogram

Furthermore, HPLC is a versatile technique which allows the separation and identification of compounds dissolved in the sample with low concentrations such as parts per trillion. The separation of components is due to the differential interactions of each component with stationary and mobile phases. Generally, these differential interactions occur due to the different polarities of components. 

What is HPTLC 

HPTLC (high-performance thin-layer chromatography) is a sophisticated form of TLC or thin-layer chromatography. Therefore, it provides a high-efficiency separation. Generally, the main difference between HPTLC and TLC is the characteristics of the separation plate. The plate used for HPTLC contains a significantly smaller particle size. It produces a higher packing density as well as a smoother surface. Therefore, with the reduction of the sample diffusion, compact bands or spots can be obtained in HPTLC. On the other hand, the thinner layer in HPTLC increases the detection sensitivity and analysis speed.

Figure 2: (A) Photo of HPTLC Plate, (B) Multi-Wavelength Scan of Mix 1, (C) Calibration Function, (D) Mass Spectra of Selected Zones, (E) Results

Moreover, the other benefits of HPTLC include higher reproducibility, sharp bands for quantitative analysis, usability in the mass spectroscopy, etc.  

Similarities Between HPLC and HPTLC 

• HPLC and HPTLC are two types of enhanced chromatography techniques. 
• Both are automated and produce highly accurate results. 
• Their main function is to separate, identify, and quantify components in a mixture. 
• Also, both use a solid stationary phase and a liquid mobile phase. 
• Moreover, they are responsible for the separation by carrying the mixture to be separated by the mobile phase along with the stationary phase. 
• Thus, it allows the absorption of components into the stationary phase based on their chemical and physical characteristics. 
• Both techniques have applications in many areas, including pharmaceutical, environmental, forensics, and chemicals.  

Difference Between HPLC and HPTLC 

Definition 

HPLC refers to a form of liquid chromatography to separate compounds dissolved in a solution, while HPTLC refers to a most advanced form of planar chromatography. Thus, this is the main difference between HPLC and HPTLC.

Abbreviation 

HPLC is high-pressure liquid chromatography or high-performance liquid chromatography while HPTLC is high-performance thin-layer chromatography. 

Type of Chromatography 

Another major difference between HPLC and HPTLC is that HPLC is a type of column chromatography while HPTLC is a type of planar chromatography. 

Mechanism 

Moreover, HPLC consists of a pump-driven flow system through the stationary phase filled in a column while HPTLC is a type of planar chromatography in which the solvent moves through a stationary phase fixed on a plate. 

Stationary Phase 

The stationary phase of the HPLC is filled into a column while the stationary phase of the HPTLC is fixed on to a plate. 

Normal or Reverse Phase 

While HPLC is mainly a reverse phase chromatography, HPTLC is normal phase chromatography. 

Open or Closed System 

HPLC is a closed system, while HPTLC is an open system. 

Pressure 

Besides, HPLC uses high pressure while HPTLC operates at atmospheric pressure. 

Time per Sample 

HPLC takes 2-60 min per sample while HPTLC takes 1-30 min per sample. 

Parallel Analysis 

Furthermore, HPLC does not allow parallel analysis while HPTLC allows parallel analysis. 

Results 

The results of HPLC come through the machine while the results of HPTLC come through either machine or by eyes. 

Resolution 

Resolution is another difference between HPLC and HPTLC. HPLC has a higher resolution, while HPTLC has a moderate resolution. 

Conclusion 

HPLC is an enhanced chromatographic technique of liquid chromatography. Therefore, it contains a solid stationary phase filled into a column. Moreover, it produces results with high efficiency and resolution. On the other hand, HPTLC is an enhanced form of thin-layer chromatography. Therefore, it contains a solid stationary phase fixed on to a plate. However, it produces moderately resolved but, high-efficiency results. Both HPLC and HPTLC are two types of automated chromatographic techniques used to separate components of a mixture. However, the main difference between HPLC and HPTLC is the type of chromatographic technique. 

References:

1. “High Performance Liquid Chromatography (HPLC).” HiQ, The Linde Group, Available Here.
2. “HPTLC.” Merck, Merck KGaA, Available Here.

Image Courtesy:

1. “Hplc-perfume-chromatogram” By Lukke – Own work (CC BY-SA 3.0) via Commons Wikimedia   
2. “HPTLCplatetoMS” 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) 5 (Attribution) via Commons Wikimedia