Interfering components present in samples must be removed before most analysis procedures. Manual sample preparation based on Gel Permeation Chromatography (GPC) is time-consuming and labor-intensive. Both time and human resources can be saved by automation of the GPC cleanup technique.
Moreover, quality and reproducibility of the cleanup are enhanced. Following sample loading, the dedicated system completely automates the processing of up to 15 samples. Mobile Control, which is a cost-effective software, offers a touch-optimized user interface for spontaneous device control directly at the system.
What Is GPC Cleanup?
GPC Cleanup is mainly employed for performing basic cleanup of a broad range of sample matrices such as plants, tissues, foodstuffs, and environmental samples. The components are separated based on their molecular size and shape because of the heterogeneous pore size of the solid phase. The column material serves as a molecular sieve. High-molecular substances such as proteins and lipids that interfere with subsequent analysis of, for example, pesticides are efficiently eliminated.
The AZURA GPC Cleanup System
The AZURA GPC Cleanup system has 15 sample loops regulated by two 16-port multiposition valves. The GPC tubing guide sorts outlet tubings originating from the fraction collection valve. The wound-up sample loops are stored in a tray that includes a drainage system and can be easily accessed for inspection and replacement. An extra multiposition valve can be used for collecting 15 fractions and waste. The manual injection valve and all the multiposition valves are combined into a compact AZURA® Assistant ASM 2.1L.
Using a variable single wavelength UV detector, elution of separated substances or standard components can be observed. A second assistant docks the small detector, the system pump consisting of a pressure sensor and a valve to circumvent the GPC column or select between two columns.
The process is performed in accordance with the following proven techniques to establish pesticide residues:
- Method 984.21—AOAC international
- AEN 12393 and EN 1528—European Standard
- L 00.00-34 Method in accordance with §64 LFGB (formerly §35 LMBG)
- SW-846 Method 3640A—US Environmental Protection Agency
The economical Mobile Control software is used for operating the GPC Cleanup System. The touch-optimized and distinctly arranged user interface can be accessed on a tablet that is directly mounted on the system.
It automatically identifies devices, thereby configuring the system with just a few finger swipes. As the setup is in the form of functional blocks such as eluent delivery, detection, sample injection, and fraction collection, programs can be rapidly developed with a marginal number of clicks.
Intuitive and touch-optimized control software Mobile Control Chrom
GPC Cleanup of Olive Oil Samples
The chromatogram of the GPC calibration standard eluted with cyclohexane/ethyl acetate (1:1, v/v) can be seen in Figure 1. The three detected pesticides were baseline separated and could be recognized easily. Figure 2 illustrates the elution profile of one olive oil sample comprising of various types of pesticides. It is evident that all pesticides were identified using the US EPA technique 3640A.
In contrast to the measurement of the standard solution, the spiked sample revealed fewer matrix effects. This indicates that all interfering high molecular elements were eliminated during cleanup. The recovery for all of the compound groups was greater than 70%.
Figure 1. Chromatogram of US EPA method 3640A calibration standard containing (1) corn oil matrix, (2) bis-(2-ethylhexyl)phthalate, (3) methoxychlor, and (4) perylene.
Figure 2. Chromatogram of olive oil sample, spiked with pesticides: (1) olive oil matrix, (2) bis-(2-ethylhexyl)phthalate, (3) methoxychlor, and (4) perylene.
GPC sample preparation is a beneficial tool for separating small quantities of target molecules from high molecular weight species.
The AZURA® GPC Cleanup System automates sample preparation and relieves the load of labor-intensive handling. Regular processing of a broad range of different sample matrices can be resolved. The setup of the 15 sample loops and one wash loop prevents cross-contamination, thereby enabling a powerful sample preparation procedure.
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This information has been sourced, reviewed and adapted from materials provided by KNAUER Wissenschaftliche Geräte GmbH.
For more information on this source, please visit KNAUER Wissenschaftliche Geräte GmbH.