Which Pumps Are Used in HPLC?

To understand the types of pumps used in HPLC, we first need to explore why high pressure is essential in the process.

Why High Pressure in HPLC?

Over the past 20 years, there has been a shift towards using smaller particles in HPLC columns. When I first joined Chrom Tech in the 90s, most of the columns we sold had a 5µm particle size. However, scientists quickly began adopting the smaller 3.5µm particle size for method development, as it allowed for greater efficiency and faster chromatography. Fortunately, HPLC pumps were able to manage the increased back pressure associated with the transition from 5µm to 3.5µm particles.

Historically, HPLC pumps had a typical maximum pressure limit of 6,000 psi (400 bar). Since most labs are trying to increase efficiency and do more work in less time, the trend is continuing for smaller particle sizes in HPLC columns, resulting in more back pressure on the HPLC pump. With the popularity of the sub 2µm particle sizes available for chromatography columns, there became a new need for an Ultra High Pressure HPLC Pump with a maximum pressure rating of 18,000 psi (1200 bar). In essence, the need for high-pressure pumps comes down to the urgency to produce better, faster separations.

What Is a Binary Pump?

Binary Pumps (two solvent gradient formation) are the most popular HPLC pumps on the market. Binary pumps are typically high-pressure mixing pumps that have gradient formation of two solvents. In reversed phase applications, you typically have Solvent A and B. Solvent A is the aqueous/buffered solvent and Solvent B is typically the organic solvent (Acetonitrile, Methanol).

What Is a Quaternary Pump?

Quaternary pumps typically use low-pressure mixing of up to four solvents to form gradients. Since this is low-pressure mixing, solvent degassing or the use of a vacuum degasser is a must. Due to gradient delays inherent in low-pressure mixing, the preferred HPLC pump for most applications is the high-pressure binary mixing pumps.

What Is an Isocratic Pump?

Isocratic Pumps deliver a single solvent for HPLC applications. We find these pumps are used for a variety of metering applications and not limited to just chromatography applications.

When using an isocratic pump for HPLC applications (or other high-performance applications), we recommend Dual-Piston isocratic pumps.

Dual-Piston Isocratic Pumps

Dual-Piston Pumps have two pistons operating in parallel, fully out-of-phase with each other, to produce naturally smooth fluid flow. This is critical for many analytical chromatography applications. Reciprocating piston pumps have the ability to produce consistent volumetric fluid flow under very high-pressure conditions. However, they do not produce pressure. System pressure results from flowing liquid through a resistive circuit (column, tubing, reactor vessel, etc.). These constant-flow pumps produce precise and predictable fluid flow dependent on system resistive pressure and the fluid being pumped.

Single Piston Isocratic Pumps

Single-Piston pumps offer an economical option for metering, dispensing, and general fluid-transfer applications. Single-piston pumps have a ‘rapid-refill’ feature drawing liquid into the pumping chamber quickly, regardless of the metered dispensing rate. This helps minimize flow pulsation. Often, these pumps are configured with a secondary pulse dampener to further smooth fluid flow.

What are the Benefits of Using HPLC Pumps?

When it comes to high-performance liquid chromatography (HPLC), the choice of pump can make all the difference. So, why should one consider HPLC pumps for their applications? Let's dive into their numerous advantages.

Consistent and Smooth Flow

HPLC pumps excel in delivering a very steady and almost pulseless flow, which is crucial when working against high backpressure. This stability ensures accurate and repeatable results, even as the backpressure fluctuates during experiments.

Precision and Reproducibility

The hallmark of HPLC pumps is their ability to maintain consistent flow rates. This consistency is vital for reproducible results, a key factor in any scientific analysis or industrial application.

User-Friendly Operation

Most HPLC pumps are available as standalone units, designed for ease of use. These models are straightforward to operate, making them accessible even for those new to HPLC technology.

Gradient Formation

HPLC pumps also offer the flexibility to create gradients, which enhances their versatility. The ability to manipulate solvent compositions opens up a range of applications, not only for HPLC but also for other analytical methods.

Versatility Across Applications

Beyond traditional HPLC uses, these pumps are adaptable to a variety of other applications, making them a versatile tool in any laboratory setting.

What Types of Liquids Can HPLC Pumps Handle?

HPLC (High Performance Liquid Chromatography) pumps are designed for versatility, capable of handling a diverse array of liquids essential for various analytical processes. Here's a closer look at the types of liquids they can manage:

• Water-Based Solutions: Excellent for use with aqueous buffers that require precise measurement and delivery.

• Organic Solvents: Ideal for situations where organic compounds are present and need specific solvent systems.

• Viscous Fluids: Designed to accommodate thicker liquids without compromising performance.

• Aggressive Chemicals: Built to withstand liquids that are corrosive or reactive, maintaining reliability even under challenging conditions.

• Radioactive Liquids: Safe handling of these sensitive materials is crucial, and HPLC pumps are equipped to manage them effectively.

• Salt Solutions: Manage solutions like brine efficiently, crucial for specific industrial and laboratory applications.

This adaptability makes HPLC pumps invaluable in research, pharmaceuticals, and various laboratory settings, providing precision and reliability across diverse liquid types.

HPLC Pumps: Industry Applications

High-Performance Liquid Chromatography (HPLC) pumps play a critical role across numerous industries due to their precision and reliability. Here's a closer look at where these pumps make a significant impact:

1. Pharmaceuticals

HPLC pumps are essential in drug manufacturing and quality control. They assist in the precise measurement and analysis of chemical compounds, ensuring that medications are safe and effective.

2. Biotechnology

In biotech research, HPLC pumps facilitate the analysis and purification of complex biological samples. They are vital in processes like protein and peptide analysis.

3. Food and Beverage

Quality control in the food and beverage industry relies on HPLC pumps to detect contaminants, ensure nutrient labeling accuracy, and maintain product safety.

4. Environmental Testing

Environmental agencies use HPLC pumps to test water, soil, and air samples for pollutants and toxins. It's a key component in preserving ecological integrity.

5. Chemical Manufacturing

In the chemical sector, HPLC pumps help in the synthesis and analysis of materials. They are crucial for quality control and product development.

6. Clinical Laboratories

Clinical labs employ HPLC pumps in diagnostics to analyze blood and other bodily fluids, aiding in the detection and monitoring of diseases.

The versatility and precision of HPLC pumps make them indispensable across these diverse fields, proving their value in both research and industry settings.

Wetted Flow Path Materials in Chrom Tech HPLC Pumps

Chrom Tech HPLC Pumps are available in various wetted materials. In addition to the primary fluid path material, Stainless Steel, or PEEK (for bio-applications), other wetted materials may include: synthetic ruby, synthetic sapphire, fluoropolymers, and UHMWPE. Stainless Steel fluid paths are most common with broad acceptance in HPLC, processing, and metering applications. Corrosion resistance, high-pressure capability, and general ruggedness make stainless steel the primary choice of materials. PEEK Pumps are used for applications where stainless steel is not chemically compatible.

Chrom Tech offers a range of low-cost, high-pressure liquid chromatography pumps; reach out to Chrom Tech to get more information on isocratic or binary HPLC pumps. Not sure which HPLC pump is best for your application? Reach out to our technical team today—we are here to help!