At Crawford Scientific our technical support centre deals with many issues regarding irreproducibility of retention and selectivity in reversed phase HPLC.  Very often, the problem lies in poor equilibration of the HPLC column between injection, which in gradient HPLC can affect the separation selectivity as well as analyte retention. We have a rule of thumb when developing methods that 10 column volumes of mobile phase, at the starting composition of the gradient, should pass through the…See More

At Crawford Scientific our technical support centre deals with many issues regarding irreproducibility of retention and selectivity in reversed phase HPLC.  Very often, the problem lies in poor equilibration of the HPLC column between injection, which in gradient HPLC can affect the separation selectivity as well as analyte retention. We have a rule of thumb when developing methods that 10 column volumes of mobile phase, at the starting composition of the gradient, should pass through the…See More

What makes a stationary phase HILIC?What is it that makes a stationary phase HILIC? I know you can use bare sililca, amine, amides, etc. and I have even heard of people running pentafluorophenyl (PFP) columns in HILIC mode. is it only that the stationary phase is very hydrophobic and that it can retain a stagnant water layer? Is there anything else that is required for a stationary phase have HILIC capabililty?See More

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The Food and Drug Administration (FDA) in the USA and the European Commission in the EU has established lists of tolerance levels, also known as maximum residue limits (MRLs) for different food contaminants in different animal edible tissues. Therefore, reliable analytical methods are needed to determine compliance with both national and international regulations in all areas of food quality and safety.In the latest issue of The Column, we…See More

Isolation and purification techniques play a massive role in drug discovery. Being able to strategically control your synthetic route is vital. In recent years both High Performance Liquid Chromatography (HPLC) and Supercritical Fluid Chromatography (SFC) have provided high quality compounds for biological testing cheaply and to time. With shorter turnaround times required, alongside increased throughput and cost restrictions, purification departments are being pushed to the limit. This is no…See More

Isolation and purification techniques play a massive role in drug discovery. Being able to strategically control your synthetic route is vital. In recent years both High Performance Liquid Chromatography (HPLC) and Supercritical Fluid Chromatography (SFC) have provided high quality compounds for biological testing cheaply and to time. With shorter turnaround times required, alongside increased throughput and cost restrictions, purification departments are being pushed to the limit. This is no…See More