Detection of organophosphorus compounds using a surface acoustic wave array sensor based on supramolecular self-assembling imprinted films
In this paper, diisopropyl methyl phosphonate （DIMP）, tributyl phosphate (TBP) and dimethyl methyl phosphonate (DMMP) were selected as organophosphorus chemical warfare agents (CWAs) simulants, an effective surface acoustic wave (SAW) array sensor coated with three self-assembled imprinted supramolecule films and two polymer coatings were prepared to detect CWAs simulants at low concentrations. As supramolecule films, 25-(thioalkyl-alkoxy)-p-tertbutylcalixarene was synthesized by two step nucleophilic substitute reaction in NaH-THF phase with p- tertbutylcalixarene and dibromodecne. 25- (thioalkyl-alkoxy)- p-tertbutylcalixarene, 1, 7, 13, 20-four-(thioalkyl-alkoxy)- resoricinarene and mono[6- Deoxy- 6-[(mercaptodecamethylene)thio]]-β-CD were coated on SAW gold delay lines by self-assembled method to detect DIMP, DMMP and TBP respectively, and the imprinted effect was proved. The response frequency shifts to DIMP had a linear relationship in the concentrations of 0.05-0.60 mg/m3, the sensitivity of SAW sensor at difference temperature was also examined, and the possible mechanism of interactions between the supramolecule coatings and DIMP was discussed. To further porve the effect of supramolecular films, a SAW array sensor was prepared with supramolecular 25- (thioalkyl-alkoxy)- p- tertbutylcalixarene, mono[6- deoxy- 6-[(mercaptodecamethylene)thio]]- β- CD, 1, 7, 13, 20- four- (thioalkyl-alkoxy)- resoricinarene and polymers SXFA and PECH for detecting DIMP, DMMP, TBP and CEES, the results indicated that the fabricated SAW array sensor was high sensitive to CWAs, and might be used to discriminated CWAs and their related compounds. To the three supramolecular self-assembly imprinted coatings, the aging experiments proved that response of the SAW array sensor might decreased about 23%, 11%, 17% respectively after 18 months storage.