- Define the customer-critical parameters
- Measure how the process performs
- Analyze the causes of imperfections
- Improve processes to minimize defects
- Control processes to ensure continued and improved performance
ES Industries has been producing HPLC columns for over 40 years during which time we have gained extensive insight into and an indepth understanding of all the factors affecting the quality and consistency of HPLC columns. This has resulted in the transformation of our company and an adaptation of a Quality Focus Program which is incorporated into every facet of our production process. Providing you with the peace of mind when selecting any ES Industries product.
The Quality Focus Program
The ES Industries Quality Focus Program (QFP) required a critical review of all our manufacturing processes starting with the silica, bonding reagents, bonding procedures, batch testing, column packing, and ending with the final column test and the institution of strict quality control procedures and parameters. The QFP is composed of five key steps which begins with the application of a systematic method for each packing material.
Ultra High Purity Spherical Silica
The finest silica based HPLC and SFC columns start with the highest quality spherical silica which is the product resulting from the control and measurement of several key parameters. It is impossible to produce high quality columns from low quality silica.
Metal Free Silica
Metal ion impurities, generally stem from the silica preparation process and from the synthesis of bonded phases and is one of the most important parameters to control during the production and use of silica, resulting in undesirable effects such as tailing and lower efficiencies. Metal ions are strong adsorption sites for complexing solutes where chelating analytes can bind directly to metal ions resulting in poor peak shape; can also increase the acidity of adjacent silanol groups, resulting in tailing of basic compounds. The presence of metal ions can influence bonding of the stationary phase, reducing coverage and increasing residual silanols.
ES Industries utilizes only the finest synthetically produced metal free ultra-high purity silica available and the metal free character of this silica is carefully protected from contamination from reagents, equipment, and material han- dling which are monitored and minimized and is tested for metal content several times before the packing materials are used to produce HPLC and SFC columns. These controls ensure that our columns provide repeatable performance for even the most challenging analysis. You, the chromatographer, can rest assured that a difficult separation is not the product of an uncontrolled metal interaction.
Controlled Particle Size, Pore Size, Surface Area, and Surface Hydroxylation
The most efficient and durable columns are produced from monodispersed particles unfortunately, even the highest quality spherical silica available is not monodispersed, and there is a distribution of particle sizes associated with all silica materials. The key to high performance spherical silica is to achieve the tightest particle size distribution possible with HPLC columns produced from a tight particle size silica material being reliable for analysis of closely eluting components.
Many analyses fail because they were developed on columns containing widely dispersed silica particles which leads to fluctuations in column efficiencies and can ultimately lead to breakdown in resolution of separated components. We obtain precise measurements of particle distributions for all bulk silica utilized and only the bulk silica that conforms to the set parameters or tight particle size distribution is released for use in production ensuring that all columns produced at ES Industries meet the highest efficiency requirements.
Other specific parameters affecting column performance include pore size distribution and surface area consistency. A bulk silica material with a poor pore size distribution will contain many micropores which will produce poor peak shapes for many components. Surface area (SA) consistency is critically important to bonded phase reproducibility and SA measurements are carefully reviewed at ES industries and only silicas with consistent surface areas can be used for our columns. As a final step, we treat all of the qualified silica before bonding to ensure that the particle surface is completely hydroxylated.
A hydroxylated surface ensures that complete surface coverage is produced during phase bonding reactions, unreacted silanol groups can lead to peak tailing and adsorption of critical analyte components. Our proprietary surface hydroxylation procedure maximizes bonded phase coverage while minimizing the number of silanol groups and yields the best deactivated columns available commercially.
Bonding Reagents and Bonding Chemistry
Once the high-quality ultra-pure silica has been established, bonding of the stationary phase is the next critical step, our extensive knowledge and experience in developing and producing bonded reagents for HPLC and SFC results in superior materials and columns. Bonding reagent purification is critically important to stationary phase consistency and reproducibility as many off-the-shelf bonding reagents are low purity, and contain significant amounts of isomers. These impurities and isomers lead to variability in the final bonded stationary phase. We carefully analyze and purify all bonding reagents to ensure consistent stationary performance.
The quality of the bonded phase does not end with stable bonding chemistry or highly purified reagents and the bonding process is only completed when the stationary phase is thoroughly washed to remove reaction by-products, catalysts, and unreacted chemicals. This cleansing procedure is a necessity for the production of stable and reproducible packing materials. Without this step the packed column bed would be unstable and baseline performance would be unacceptable. We subject all of our packings to a battery of washing procedures which yield high quality packings that produce columns of unmatched performance and stability.
Column Packing and Hardware
One of the most important parts of the whole HPLC column production sequence is the packing of the column. Stationary phases have been carefully prepared and washed, but unless these materials are packed with the highest precision possible, the integrity of the packing material can be lost. Over the last 40+ years of HPLC column production, we have developed and refined techniques for packing columns and now utilize the most advanced column packing technology in the industry. This technology enables us to pack the finest columns available across a wide variety of internal diameters from 0.5 mm to 4 inch and in lengths from 10 mm to 500 mm.
A significant part of our superior packing technology resides in unsurpassed column hardware where only end fittings and column tubing of the highest quality and performance are acceptable and our strict performance criteria for stainless steel columns also apply to PEEK and glass lined columns. Stainless steel column tubing with highly polished, mirrored finished internal bores are used. As a result, the chromatographer can be confident that they are receiving the highest quality column hardware in the industry.
Every step of our column production sequence is strictly monitored and controlled by an extensive battery of tests which are applied to all steps including silica particle formation, bonding reagents and reactions, column hardware, and packing which ensure the quality of the final product – with each test designed to measure a customer-critical parameter.
The final batch test for each product has been carefully designed and tailored to test the performance standard set for each phase and each column is tested individually to check the integrity and performance of the packed bed.
Every ES Industries column is guaranteed to deliver the highest plate counts and most symmetrical peaks for even the most difficult analysis. We are confident the Quality Focus Program will deliver the highest quality and most reliable HPLC columns available to you, HPLC chromatographer.