Study On The Fabrication And Analytical Performance Of Colorimetric Sensor Arrays For The Discrimination Of Small Organic Molecules

Small organic molecules?SOMs?are common industrial raw materials and pollutants severely impairing ecological environment and life,which are also considered as potential biomarkers of some diseases and flavoring substances of food.In general,SOMs are closely related to industrial production,environmental monitoring,medical diagnosis and food safety.Therefore,it is of important significance to identify and detect SOMs.Cross-responsive colorimetric sensor arrays have many advantages,such as simple,cheap,rapid,visual,handy,etc.,enabling them serving as an ideal alternative method to detect SOMs.In this work,colorimetric sensor arrays were constructed to discriminate specifically and detect quantitatively organic acids and aldehydes,respectively.Additionally,a nanoporous dyes-based colorimetric sensor array using functionalized dyes with nanomaterials was developed for fast recognition of various gases of SOMs.The main contents of this work carried out are as follows:?1?A colorimetric sensor array based on indicator displacement assay for the discrimination and detection of organic acidsDyes-metal ions complexes,including murexide-Ni²⁺,murexide-Cu²⁺,zincon-Zn²⁺and xylenol orange-Cu²⁺,were used as sensing units to construct a 3×3 colorimetric sensor array.Based on indicator displacement assay?IDA?among dyes,metal ions and organic acids,the array achieved fast discrimination for 14 important organic acids within 5 minutes with high classification specificities and accuracies of>92%.In addition,the IDA array exhibited excellent ability to quantitatively detect pyruvic acid,which showed a good linear range of 10¹500?M and a detection limit of 3.45?M,accompanying good recovery rates in real samples of human serum and Chinese liquors ranging from 84.8%to 114.3%.The experimental results showed an excellent anti-interference ability and a great repeatability of the IDA array.?2?Detection of aldehydes with a GNPs-based colorimetric sensor array based on silver mirror reactionA GNPs-based colorimetric sensor array was constructed successfully to differentiate 10 aldehydes at low concentrations based on silver mirror reaction between aldehydes and Tollens'reagent.Silver from reduction of Ag⁺was coated onto GNPs,leading to the formation of Au@Ag core-shell nanostructures and consequently resulting in the significant color change of GNPs solution.Good specificities and accuracies of>90%were obtained for all aldehydes except for isobutyraldehyde.Furthermore,the array presented a good linear relationship between responsive signals and logarithms of concentrations of formaldehyde in the wide range of 0.05?M to50000?M with a low detection limit of 0.03?M.Moreover,the array exhibited excellent selectivity and reproducibility for aldehydes,indicating the array had good performances to detect aldehydes.?3?Fast recognition of volatile gases of SOMs with a nanoporous dyes-based colorimetric sensor arrayIn order to enhance the abilities of colorimetric sensor arrays for the recognition of SOMs,four nanomaterials including silica hydrogel?Sol-gel?,gold nanoparticles?GNPs?,graphene oxide?GO?and molybdenum disulfide quantum dots?MoS₂ QDs?were prepared and characterized by TEM,FT-IR,XPS,etc.Based on functionalized dyes with above nanomaterials,a nanoporous dyes-based colorimetric sensor array was developed for fast recognition of 16 volatile gases in 4 minutes including organic acids,aldehydes,ketones,alcohols,alkanes,aromatics and so on.Specificities and accuracies of analytes were larger than 91%.Additionally,the array showed an excellent stability against the changes in humidity or temperature over a wide range with a good batch to batch reproducibility.All results implied that the dyes functionalized with nanomaterials is one of most promising paths to improve the analytical performance of arrays for SOMs discrimination applications.