Synergistic integration of centrifugal ultrafiltration and superhydrophilic substrates for enhanced sensitivity and stability in laser-induced breakdown spectroscopy

Minor variations in serum element concentrations are linked to many diseases, emphasizing the need for sensitive and stable detection methods. Serum analysis faces challenges due to macromolecular interference and non-uniform sample distribution caused by the coffee-ring effect. To address these limitations, a novel methodology integrating centrifugal ultrafiltration with superhydrophilic surface-enhanced laser-induced breakdown spectroscopy (CUSHL-LIBS) has been developed. Centrifugal ultrafiltration isolates macromolecules, reducing interference, while the superhydrophilic substrate suppresses the coffee-ring effect, ensuring uniform sample distribution. Experiments show that this method produces higher plasma signal intensity in serum filtrate than in whole blood or plasma. Repeatability assessments reveal relative standard deviations (RSDs) of 4.49% for calcium (Ca) and 1.98% for potassium (K), whereas quantitative analyses demonstrate detection limits of 0.31 mg L⁻¹ for Ca and 0.61 mg L⁻¹ for K. These results demonstrate that the CUSHL-LIBS method offers an innovative solution for high-sensitivity and high-stability elemental analysis, with significant potential applications in clinical diagnostics, medical research, and personalized treatment strategies.