Logistics Delay- An important notice

Due to the current COVID-19 situation in China, all of our logistics are being affected. Specific shipments may be delayed due to the circumstances. We are sorry for any kind of inconvenience during these days. Kindly stay with us. We will constantly keep you updated. If you have any problem or require further information, please contact info@welchmat.com

The importance of a stable pH environment in HPLC detection

In liquid chromatography, buffer solution is often added to the mobile phase, one of the purposes is to make the entire HPLC system charge a stable chemical environment, so that the detection has better reproducibility. If the pH of the system is not stable enough, there will be various problems such as drift of retention time, unreproducible retention time of multiple detections, multi-component peak sequence, inconsistent peak composition and so on. Especially in the detection Read more…

Case sharing – take you to understand the separation of peptides

1. Properties of peptides Polypeptide is a compound formed by connecting multiple amino acids in sequence. Amino acids are amphoteric compounds with the characteristics of zwitterions. 2. Factors Affecting Peptide Separation Column packing pore size (120Å, 300Å) Additives and concentrations (formic acid, ion pair reagents) pH Elution solvent (acetonitrile, methanol, isopropanol) Gradient Temperature Flow rate Pore ​​size refers to the diameter of the pores on the silica ball. Molecules enter the pores and are adsorbed Read more…

New arrivals – Perfect match of medium pressure glass column and packing materials

What kind of strange chemical reaction will happen when the medium pressure glass column meets the bulk media? It is a high-efficiency purification tool, a low-cost purification method, and a new user experience. Let medium pressure chromatography speed up purification, save time for yourself, and make “passing the column” no longer difficult! Advantages of medium pressure glass columns ● High column efficiency: the longer the column length, the higher the column efficiency, and high-purity samples can Read more…

A Brief Talk on Ion Pair Chromatography

When you are doing daily testing, you will find that some items, such as sodium heptane sulfonate, tetrabutylammonium hydroxide, tetrabutylammonium bromide and other reagents are added to the mobile phase used in the test standard. We call these reagents ion pairing Reagents, which can be used to improve separation and peak shape, narrow the retention range of samples, etc. Ion pairing reagents can be seen as a manifestation of the introduction of ion chromatography in Read more…