Standards in the extraction phase, a new approach to calibration of microextraction processesElectronic supplementary information (ESI) available: Materials and methods. See http://www.rsc.org/suppdata/an/b4/b406310d/

Abstract

A standard, preloaded onto the extraction phase prior to the extraction step, partially desorbs to the sample matrix during sampling. The amount lost can be used as a means of calibration.

In vivo solid-phase microextraction for single rodent pharmacokinetics studies of carbamazepine and carbamazepine-10,11-epoxide in mice

“…A kinetic on-fibre standardization calibration method was used for in vivo PK and in vitro validation experiments [4,8,[19][20][21]. Simultaneous pre-conditioning and pre-loading of the in vivo probes were performed using 1000 ng/mL standard solution of CBZ-d10 calibrant prepared in methanol/water (1/1, v/v) for a minimum of 120 min with 1000 rpm vortex agitation, which was sufficient to reach equilibrium [18].…”

Comparison and validation of calibration methods for in vivo SPME determinations using an artificial vein system

“…To date several pre-equilibrium extraction calibration methods were developed and derived by a proposed theoretical model based on a diffusion-controlled mass transfer processes [11,12]. Using the proposed model, Chen et al demonstrated the feasibility of using the desorption process to calibrate the extraction process since a symmetric relationship existed between the amount of standard desorbed from the fibre and the amount of analyte extracted from the sample matrix [13,17,18]. This kinetic calibration, called on-fibre standardization (OFS), was subsequently applied to the pharmacokinetic studies of beagles [1,3,4] and rats [5].…”

“…In contrast, fibres with thicker coatings (45 m) were recently developed by Supelco and aimed for single-use in vivo with good inter-fibre reproducibility [10]. For these fibres or any fibres with thick coatings [10], pre-equilibrium extraction in combination with kinetic calibration offers an alternative sampling method for in vivo studies [11][12][13][14][15][16][17][18][19][20]. To date several pre-equilibrium extraction calibration methods were developed and derived by a proposed theoretical model based on a diffusion-controlled mass transfer processes [11,12].…”

Automation of solid‐phase microextraction

“…It also allows calibration in non-uniform agitation conditions. To maximise reproducibility, the internal standard loading step and extraction procedures have been fully automated [53,54]. To obtain a reproducible, workable loading of the internal standard on the fibre it was necessary to use a loading solution of the internal standard in vacuum pump oil.…”