| Acrylamide (AM), a well-known neurotoxic compound, has been found with especially high levels in potato chips, french fries, and other food products produced with high-temperature cooking, which can damage the human nervous system and reproductive system. It is very important to detect AM in food.In this work, we have developed a sensitive molecularly imprinted electrochemical sensor for detection of the AM. It is based on a glassy carbon electrode (GCE) modified with a composites prepared from gold nanoparticles (Au NPs), multiwalled carbon nanotubes (MWCNTs) and chitosan (CS) along with a sol-gel based molecularly imprinted polymer (MIP) film. HPLC analysis was also conducted to detect AM in the same samples and underpinned the applicability of the electrochemical MIP sensor. The MIP sensor offers advantages for detection of AM, with (i) good selectivity, (ii) good sensitivity and (iii) low cost, and was used for AM determination in potato chips samples successfully. In addition, repeatability and storage stability of the MIP sensor are also reliable. The main results as follows:(1) The Au NPs of 17 nm were synthesized by the sodium citrate chemical reduction method. And the Au NPs-MWCNTs composites were obtained through Au-S bond.(2) The imprinting conditions had been optimized, he results indicated that the optimal monomer/cross-linker ratio was 1:4, pH was 8.0, addition of template molecule was 0.055 g, eluent was 100% ethanol, incubation time was 30 min.(3) The MIP/MWCNTs-CS/GCE and NIP/MWCNTs-CS/GCE sensor for the determination of AM was structured. The results indicated that only MIP sensor had special selectivity for AM. The MIP sensor, when operated at a working voltage of 0-0.4V, has a linear response range to AM in the 0.2 to 10.0 ug/mL range. The linear regression equation was expressed as I (ΔμA)= 5.78 c (μg/mL)+0.10 (R2=0.9878), with a lower detection limit of 0.079 μg/mL (S/N=3).(4) The MIP/Au NPs-MWCNTs-CS/GCE sensor for the determination of acrylamide was structured. The MIP sensor, when operated at a working voltage of 0-0.4 V, has a linear response range to AM in the 0.05 to 5 μg/mL range. The linear regression equation was expressed as I (Δ μA)= 16.5 c (μg/mL)+2.17 (R2= 0.9880), with a lower detection limit of 0.028 μg/mL (S/N= 3). The content of AM detected based on MIP sensor was 148μg/kg (RSD:5.51%) in the potato chips sample, the recovery was in the range of 84.7% to 94.8%. The proposed MIPs sensor has the acceptability stability in nine days.(5) The HPLC method was used to detect AM. The HPLC has a linear response range to AM in the 0.71 μg/mL-4.26 μg/mL. The linear regression equation was expressed as y=6010x-5048(R2=0.997), with a detection limit of 0.24 μg/mL (S/N=3). The content of AM detected based on HPLC was 134.3 μg/kg (RSD:2.79%) in the potato chips sample. The recovery was in the range of 83.4% to 90.5%. The results indicate that the MIP/Au NPs-MWCNTs-CS/GCE sensor for detecting acrylamide is reliable, and had a better sensitivity than the HPLC. The cost was also much lower than the HPLC method, which will has more important practical applications for detection of AM. |
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