Micelle-dominated distribution strategy for non-matrix matched calibration without an internal standard:...

The analysis of trace hydrophilic targets in complex aqueous-rich matrices is considerably challenging, generally requiring matrix-matched calibration, internal standard, or time-and-labor-intensive sample preparation. To address this analytical bottleneck, a non-matrix-matched calibration strategy without using internal standard was reported for the first time to analyze complicated biosamples such as whole blood, plasma, serum, and cell samples. This strategy, termed micelle-dominated distribution, also aimed at realizing the simple "extract-and-shoot" analytical process for such complex matrices. The micelle-matrix interaction was found to efficiently eliminate the matrix effect by dominating phase separation and analyte distribution between the extraction and matrix phases. Thus, calibration linear curves prepared in water were applicable to the analysis of all the above-mentioned sample types. Rapid distribution equilibrium within 4 min was achieved. This strategy could tolerate direct large volume injection, thereby providing two-order-of-magnitude enhancement in the sensitivity of ion-pair chromatography. The analytical method integrated cell rupture, matrix cleanup, analyte extraction, and on-column preconcentration into a fast and high-throughput operation. The successful application to the determination of exogenous pesticides and endogenous glutathione exhibited low limits of detection (0.0085-0.015 μg mL^-1 for pesticides; 0.52 μg mL^-1 for glutathione), wide linear ranges (0.028-50 μg mL^-1 and 0.049-50 μg mL^-1 for pesticides; 1.7-1000 μg mL^-1 for glutathione), good linearies (R² = 0.9994-0.9999), excellent accuracy (recoveries of 91.3-105.2%), and good precision (0.7-6.2% at the levels of 0.028 (or 0.049), 0.1, 0.5, and 50 μg mL^-1 for pesticides; 0.5-8.7% at 1.7, 500, and 1000 μg mL^-1 for glutathione).