Ultrasensitively sensing acephate using molecular imprinting techniques on a surface plasmon resonance sensor

Area of Science:

• Analytical Chemistry
• Materials Science
• Biosensing

Background:

• Organophosphate pesticides like acephate pose significant environmental and health risks.
• Accurate and sensitive detection methods are crucial for monitoring pesticide residues.
• Surface plasmon resonance (SPR) offers label-free detection capabilities.

Purpose of the Study:

• To develop an ultrasensitive and selective SPR sensor for acephate detection.
• To fabricate an ultrathin molecularly imprinted polymer (MIP) film on an Au surface for enhanced acephate binding.
• To evaluate the sensor's performance in terms of sensitivity, selectivity, and applicability to real samples.

Main Methods:

• Fabrication of an ultrathin MIP film on an Au surface using a surface-bound photo-radical initiator.
• Polymerization in the presence of acephate to create specific binding sites.
• Utilizing SPR to monitor wavenumber changes upon acephate binding.
• Assessing selectivity against structurally related analogues.

Main Results:

• The SPR sensor demonstrated ultrasensitive detection of acephate with a high association constant (K(ass) = 7.7×10(12) M(-1)).
• The MIP film exhibited excellent selectivity for acephate over analogues (selectivity efficiencies of 1.0 vs. 0.11-0.37).
• Achieved low detection limits (1.14×10(-13) M for apple, 4.29×10(-14) M for cole) with good recoveries and precision.

Conclusions:

• The combination of SPR sensing and MIP film is a highly effective strategy for organophosphate detection.
• This developed sensor offers a promising alternative for the sensitive and selective analysis of acephate in food samples.
• The method shows potential for widespread application in pesticide residue monitoring.