| Abstract: | The coadsorption of mixed anionic–nonionic surfactants, sodium dodecylbenzenesulfonate with Triton X‐100, on the surface of eggshell membrane was investigated based on adsorption isotherms to improve the solid‐phase extraction performance of eggshell membrane toward organic contaminants. Results showed that even though excess Triton X‐100 might inhibit the adsorption of sodium dodecylbenzenesulfonate, a low dosage of Triton X‐100 can significantly improve sodium dodecylbenzenesulfonate modification and enhance the extraction efficiency of eggshell membrane from 73.7 to 100.4% because of the formation of mixed hemimicelles. The highest recovery was achieved at 2:8 (Triton X‐100/sodium dodecylbenzenesulfonate mass ratios), and multiple mechanisms involving π–π interactions, hydrophobic effect, and π–π electron donor–acceptor interactions contributed to the strong extraction affinity. When mixed, the Triton X‐100 and sodium dodecylbenzenesulfonate modified eggshell membrane packed cartridge coupled with high‐performance liquid chromatography was applied for the simultaneous determination of trace Sudan I–IV, and low detection limits (0.16–0.26 ng/L) were achieved with satisfactory linearity (R 2 > 0.999) in 10–10 000 μg/L. For real samples, Sudan II and III in one chilli sauce sample were found at 4.3 and 1.7 μg/kg. Sudan I–IV recoveries at three spiked levels were 87.4–102.9% with precisions <6.8%. Comparison with commonly used solid‐phase extraction adsorbents and methods further reflected the superiorities of the proposed adsorbent in sensitivity, retention ability, and applicability. |
