Doubly imprinted polymer nanofilm-modified electrochemical sensor for ultra-trace simultaneous analysis of glyphosate and glufosinate.
A rapid, selective, and sensitive double-template imprinted polymer nanofilm-modified pencil graphite electrode was fabricated for the simultaneous analysis of phosphorus-containing amino acid-type herbicides (glyphosate and glufosinate) in soil and human serum samples. Since both herbicides respond overlapped oxidation peaks and only glyphosate is prone to nitrosation, n-nitroso glyphosate and glufosinate were used as templates for obtaining the well-resolved quantitative differential pulse anodic stripping voltammetric peaks on the proposed sensor. Toward sensor fabrication, a nano-structured polymer film was first grown directly on the electrode via initial immobilization of gold nanoparticles at its surface. This was followed by linking of monomeric (N-methacryloyl-l-cysteine) molecules through S-Au bonds. Subsequently, these molecules were subjected to free radical polymerization, in the presence of templates, cross linker, initiator, and multiwalled carbon nanotubes as pre-polymer mixture. The modified sensor observed wide linear ranges (3.98-176.23 ng mL(-1) and 0.54-3.96 ng mL(-1)) of simultaneous analysis with detection limits as low as 0.35 and 0.19 ng mL(-1) (S/N=3) for glyphosate and glufosinate, respectively, in aqueous samples. The respective oxidation peak potentials of both analytes were found to be substantially apart by 265 mV. This enabled the simultaneous determination of one target in the presence of other, without any cross reactivity, interferences, and false-positives, in real samples.
Analytical Division, Department of Chemistry, Faculty of Science, Banaras Hindu University, Varanasi 221005, India. Electronic address: prof.bbpd@yahoo.com.
Bhim Bali
BB
Prasad
Analytical Division, Department of Chemistry, Faculty of Science, Banaras Hindu University, Varanasi 221005, India.
Darshika
D
Jauhari
Analytical Division, Department of Chemistry, Faculty of Science, Banaras Hindu University, Varanasi 221005, India.
Mahavir Prasad
MP
Tiwari
D000613:Aminobutyrates / Q000032:analysis* / Q000097:blood; D055664:Electrochemical Techniques / Q000295:instrumentation*; D004867:Equipment Design; D005998:Glycine / Q000031:analogs & derivatives* / Q000032:analysis / Q000097:blood; D006540:Herbicides / Q000032:analysis* / Q000097:blood; D006801:Humans; D057230:Limit of Detection; D054802:Molecular Imprinting; D049329:Nanostructures / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D012987:Soil / Q000737:chemistry; D014867:Water / Q000032:analysis; D000097797:Glyphosate
D000613:Aminobutyrates; D005998:Glycine; D006540:Herbicides; D011108:Polymers; D012987:Soil; D014867:Water; D000097797:Glyphosate; C003121:phosphinothricin
Differential pulse anodic stripping voltammetry; Double template imprinted polymer film; Glufosinate; Glyphosate; Gold nanoparticle; Simultaneous ultra-trace analysis