Engineering Grey Nanosystem as Activatable Ratio-colorimetric Probe for Detection of Lead Ions in Preserved Egg

Abstract

A grey system based on the principle of complementary colors was constructed as an activatable probe for sensitive and specific Ratio-colorimetric detection lead ions (Pb 2+) in complex food matrix. This grey system was prepared through mixing purple-red AuNPs-capped glutathione (GSH) and green-blue sulfonated pigment green 7 (SPG7), named SPG7/AuNPs probe. In the presence of Pb 2+ , the strong chelation of Pb 2+ with GSH could trigger the aggregation of AuNPs, leading to the color activation of SPG7. Hence, the absorbance ratio A523 nm/A628 nm of AuNPs at ~ 523 nm and SPG7 at ~ 628 nm could be used for highly-specific reporting of Pb 2+ levels with a low detection limit of 0.33 g/L. Moreover, this probe exhibited promising practical applications in real preserved egg samples with recoveries of 89.2% to 107.5% and relative standard deviations (R. S. D.)in the range of 0.28% to 2.12%, revealing its great potential in harmful substance detection.

Use of Incinerated Eggshells to Produce Pidan

“…Uncontrolled doses of metal ions used Sustainability 2022, 14, 6797 2 of 9 to minimize pickling and maturation times increase the heavy metal residues in pidan, which influences the food's safety and quality. The previous process used lead (Pb 2+ ) as the main addition of divalent metal ions until the lead was reported as hazardous to human health [17,18]. Many results indicated that preserved eggs formed with PbO, CuSO 4 , FeCl 3 , ZnSO 4, and CuSO 4 /ZnSO 4 preparation are potentially dangerous to human health.…”