Categories
Troubleshooting

WebEx. The future of instrumental services?

Online communicationI had to solve connection problem in between the Bruker MS and Agilent LC (Agilent shutdown). On the very end, I found out there was no problem in their mutual communication. However, it shows me the future of the instrumental services. WebEx communication.

Categories
Troubleshooting

Agilent 1100 shutdown

Agilent 1100
Agilent 1100

From time to time, we all face problems with HPLC instruments. Then, we all search the internet for the solution for our problem. In this troubleshooting section I would like to point out my problems with instruments and their solutions. Hopefully, it can help also you.

Recently, I was asked to run the HPLC-MS instrument which was off for several months. The LC part was Agilent 1100 and MS was from the Bruker (HCT+). The instruments themselves worked fine, but there was a problem with their connection. At least I thought so. The Agilent HPLC went always to power off mode after couple of minutes. No matter what I have done, no matter what I have tried. It always went to shutdown mode.

Categories
Chromatography

Inverse size-exclusion chromatography

Calibration curve in inverse size-exclusion chromatography (Ve/Vc - elution volume of the polymer divided by the volume of the column, log Mr - logarithm of (polystyrene) molar mass)
Calibration curve in inverse size-exclusion chromatography (Ve/Vc - elution volume of the polymer divided by the volume of the column, log Mr - logarithm of (polystyrene) molar mass)

The inverse application of the size-exclusion chromatography (SEC) concept, inverse size-exclusion chromatography (ISEC) [1], utilizes a set of molecular probes with defined sizes to determine pore dimensions, and is also referred as chromatographic porosimetry [2].

Categories
Chromatography

Stationary phase: superficially porous particles

Superficially porous particles with thicker outer shells were used extensively for liquid-liquid chromatography [1] and as the support for early bonded-phase packings in reverse phase HPLC [2].

Categories
Chromatography

Stationary phase: non-porous particles

Non-porous polymer particles
Non-porous particles (crawfordscientific.com)

It is known that the kinetics of mass transfer in wide pore bonded silica can be slow, because of restricted intraparticle diffusion and, furthermore, remaining active surface sites can give rise to undesired interactions.