How to Improve Peak Shape Consistency in Multiresidue Pesticide Analysis

by | Environmental

Agilent Technoloies has produced an application note demonstrating how the Agilent Intuvo 9000 gas chromatograph addresses issues associated with multiresidue pesticide analysis of food products and offers the additional advantage of an innovative inert flow path.

Multiresidue pesticide analysis has become the prevalent method for analysis of food products because it allows the simultaneous determination of multiple pesticides, the number of which is continuously increasing. QuEChERS is the preferred method for sample preparation. It reduces the matrix load, but does not produce a clean sample. Despite sample cleanup, pesticide analysis can suffer from reduced response and increasingly asymmetric peaks over time. Reducing batch size or increasing the frequency of inlet or column/retention gap maintenance can be a reasonable solution for conventional gas chromatograph systems.

The Solution – using the Agilent Intuvo 9000 Gas Chromatgraph
Agilent_Intuvo_9000.pngThe Agilent Intuvo 9000 gas chromatograph offers a redesigned modular flow path featuring a reimagined retention gap that protects the analytical column from matrix, and eliminates the need to trim the column. The innovative flow path aids in maintaining chromatographic integrity (response and peak shape) for even the most challenging analytes. Lastly, the Intuvo 9000 GC is only 27 cm wide affording additional flexibility, especially in laboratories with limited bench space.

Results and Discussion
After calibrating with the tea extract (consisting of 24 injections), the 50 ppb standard was evaluated to determine whether it was still within a 70–120 % recovery window. Upon passing that specification, 60 injections of the 50 ppb standard (with matrix) were made. After the 60 matrix injections were completed, the liner and Intuvo Guard Chip were replaced to mimic the maintenance often performed after batch analyses on conventional GC systems.

Analysing pesticides with the Agilent Intuvo 9000 GC using a 15 m Intuvo HP-5ms Ultra Inert Column yields consistent results throughout the batch. Peak shape is well maintained throughout calibration and matrix samples. For the application shown here, nearly 100 injections were performed before maintenance was performed.

Published  Jul 5, 2017

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