Characteristics of a novel on-line micro pressurized liquid extraction method

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2020-10-05
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Abstract
A novel on-line micro pressurized liquid extraction (μPLE) method is introduced, which directly interfaces miniaturized solid sample preparation with HPLC for fast analysis. The technique employs rapid heating to remove analytes from 5-10 mg samples in typically 20-40 seconds using only about 300 μL of solvent. The resulting extract is then internally transferred to an HPLC injector for chromatographic analysis. Results show that good analyte recoveries can be achieved, similar to conventional PLE and off-line μPLE approaches, without manual sample handling. For example, 103 ± 3% (n= 4) of the acetylsalicylic acid present in pharmaceutical tablets was extracted into methanol after 20 seconds at 180 oC. Further, 105 ± 9% (n= 4) of the caffeine present in a green tea sample was extracted into methanol after 40 seconds at 275 oC. Typical time to analysis was about 95 seconds total for most samples and solvents could also be easily alternated during trials to increase extract selectivity. The on-line μPLE system was applied to the extraction of model PAHs from a biochar matrix and was found to extract 97 ± 5% (n= 4) of anthracene present in the sample after a 30 second static and 60 second dynamic extraction at 220 oC. This yield is much better than results obtained by previous approaches and is attributed to the small size, high temperature, low thermal mass, and dynamic flow of the system. Findings indicate that the on-line μPLE system can greatly assist in such extractions and provide a useful method for rapidly preparing solid samples for analysis using little solvent.
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Taylor, B. M., & Thurbide, K. B. (2020). Characteristics of a novel on-line micro pressurized liquid extraction method. "Canadian Journal of Chemistry". http://dx.doi.org/10.1139/cjc-2020-0107. pp. 1-27.