Liquid phase online sample preparation techniques possess lot of benefits over offline sample preparation techniques. Through online coupling, advantages of solid phase extraction (sample clean-up and pre-concentration) and direct injection (sample analysis) techniques can be achieved. Due to elimination of the most significant error source (human factor) from the sample handling process, online sample preparation techniques can significantly increase overall efficiency: reduce sample preparation time, operational costs and simultaneously increase both method repeatability and reproducibility values.On-line coupling of sample preparation (trap) and conventional HPLC or (U)HPLC columns can be performed in many different ways: wide variety of column materials and separation principles are available and can be combined in order to achieve effective clean-up and/or enrichment on the trap column (conventional SPE, size exclusion, turbulent flow etc...) and further, complete separation on the coupled analytical column. Orthogonality is key parameter for efficient and selective online system performance, however it is often difficult to apply or ignored resulting in complicated or even impossible method set-up or optimisation.   Online sample preparation methods are recently widely used in clinical laboratories, however only few applications are known for food safety relevant compounds. This presentation aims to fill a gap and report on special hardware set-up making even non-orthogonal online systems capable to perform according to the current legislation requirements for multi-residue pesticide applications. Developed online clean-up and pre-concentration method for 50 broad spectrum pesticides (very polar to apolar) in different liquid or solid matrices will be shown and established method performance parameters (matrix effect, detection limit, intermediate precision, and method bias) presented.

High efficient online sample preparation methods for pesticide residue analysis

248th National Meeting (2014)

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