Chromatography

Capillary GC column installation

Brief procedure for column installation

• Cool all heated zones of GC
• Check gas purifiers and if they are spent, replace them.
• Clean injector and detector
• Replace injector/detector liners with new ones.
• Replace critical injector and detector seals.
• Replace septum in the injector.
• Set make-up and detector gas flow rates.
• Carefully inspect the column for damage or breakage.
• Install a nut and ferrule on each end of the column.
• Cut 10 centimeters from each end of the column. Use a sapphire scribe or ceramic scoring wafer to cut fused silica capillary columns. Use the serrated edge of a ceramic scoring wafer or the edge of a sharp file to cut metal capillary columns. See our catalogue for capillary cuting tools.
• Mount the capillary column in the oven using a bracket that protects the column from becoming scratched or abraded.
• Insert column the appropriate distance into the inlet as indicated in the instrument manual.
• Install the column so that the capillary does not touch the oven walls.
• Set the approximate column flow rate by adjusting the head pressure to the value listed on the test chromatogram included with the column.
• Set split vent, septa purge, and any other applicable inlet gases according to the instrument specifications.
• Confirm the flow by immersing the column outlet in a vial of solvent (acetone or isopropyl alcohol).
• Insert column the appropriate distance into the detector as indicated in the instrument manual.
• Check for inlet and outlet leaks using a thermal conductivity leak detector. Do not use soaps or liquid-based leak detectors or the column may be damaged.
• Set injector and detector temperatures. Turn the detector on when the temperatures have equilibrated. Caution - do not exceed the phase's maximum operating temperature!
• To set the proper dead time (linear velocity), inject methane or a non-retained substance compatible with the detector being used.
• Verify system integrity by checking the dead volume peak. It should not tail.
• Condition the column at its maximum operating temperature to stabilize the baseline. (See the test chromatogram included with the column for the maximum temperature.)
• Set oven to appropriate temperature and inject methane or an appropriate unretained substance, again to set the proper linear velocity.
• Inject a duplicate of the original test mixture or your specific test mixture to confirm proper installation, system, and column performance.
• Calibrate the instrument and inject samples.

Note: If the column is new, you have to run conditioning procedure prior setting the proper dead time.

GC Column conditioning

Conditioning at elevated temperatures without flow will permanently damage or destroy the performance of the capillary column. Conditioning with an oxygen leak present causes the column bleed and destroys its utility at high operating temperatures. Therefore prior the conditioning a column:

• Check proper carrier gas flow settings
• Make a leak test to verify that there is not oxygen present in the system

GC column conditioning:

• Install the column to the injector. Do not connect the column to the detector. Leave the column end in the GC oven.
• Set the GC oven to 40°C
• Hold this temperature 15 minutes
• Set the temperature gradient to 10°C/min
• Set the maximum operation temperature 20°C above your final temperature of the GC temperature program (the maximum temerature must be 25°C below the column maximum operating temperature)*
• Leave the column at high temperature ovenight until the baseline stabilizes. If the column is pre-conditioned, leave tha maximum temperature for 2 hours and untill the baseline stabilizes.

^*Note: Overnight conditioning is not necessary with pre-conditioned columns. Read carefully the conditioning instructions supplied by the column manufacturer. They have priority to the general conditioning recommendation above .

EasyFlash columns

Chromservis has launched new EasyFlash columns for high efficient flash chromatography. In this article, you will learn about the Flash chromatography benefits.

HPLC connections (TN #539)

This technical note shows possible types of connection between column and LC system. Bad connection may influence peak separation and should be avoided. The right connection is presented below.

How the Triple Quadrupole works?

The principle of Triple Quadrupole (TQ) is explained on EVOQ™ system by Bruker. The key points of the system are:

• Axial Ion Source
• Active Focusing Q1
• Lens-Free Ion Path
• 180° Collision Cell
• Elliptical Design
• Off Axis Detector

puriFlash

puriFlash^® Flash Cartridges

Interchim developed new technique for flash chromatography - Ultra Performance Flash Purification (UPFP) using special flash cartridges. The flash cartridges are in the form of regular or irregular silica. UPFP enables to run purifications with high purity of the yield and less solvent use.

Preparative LC

Task for preparative HPLC systems differs to analytical one. While analytical HPLC task is qualitative and quantitative determination of defined compounds in samples, preparative HPLC task is separation, purification and isolation of value products from mixtures.

Preparative chromatography can be devidet into three main areas:

• Semi-preparative separations
• Batch preparative chromatography (pilot or industrial scale)
• True Counter-current chromatography
• Simulated moving bed (SMB)
• Continuous chromatography

Scale definition

Preparative chromatography can be conbined with Flash chromatography in one system - purification device. The PuriFlash (Advion-Interchim) offers different modes of operation:

• Preparative line + Flash line
• Two Flash lines
• Two Preparative lines.

Introduction

Amino acids are key building blocks of life and play pivotal role in various metabolic pathways. They mostly act as intermediates often not directly involving proteins. Due to their chemical complexity and dynamic range, their reliable quantitative and qualitative analysis in biological fluids and tissues is crucial for nutritional information, compound identification and diagnostics.

For that purpose, a simple, elegant and thus far the most expeditious method for an invaluable amino acid analysis has been developed. LC/GC-MS based Metamino® kit offers comprehensive solution up to 75 metabolites including basic proteinogenic amino acids, biogenic amines and coenzymes with the possibility to a further analyte extension.

Features

• In principle suitable for any matrices (urine, blood serum, tear, cerebral liquid, tissue extracts, soil extracts, etc.)
• Easy sample preparation
• Sample derivatization and analysis under 20 minutes
• Broad portfolio of analytes (75) with the possibility for a further extension
• No sample heating/ freezing needed
• NIST Library for GC/MS available
• Possible to determine substances with a low molecular weight that can be degraded in the ion source (e.g., GLY, ALA, etc.)
• Suitable for the analysis of substances that are difficult to quantify, such as polyamines
• All necessary reagents, accessories, HPLC column and clear instructions for derivatization and analysis with high accuracy and sensitivity are included

Allowable Adjustments to HPLC Methods

Chromservis HPLC columns corresponding to USP and Eur. Pharmacopoeia methods and the extent to which the various parameters of a chromatographic test may be adjusted without fundamentally modifying the pharmacopoeial analytical procedures are listed in this technical note. Changes other than those indicated require revalidation of the procedure.