Development of fluorescent sensor for environmental
Transcription
Development of fluorescent sensor for environmental
Author’s preference: oral Development of fluorescent sensor for environmental pollutants from quenching of novel functional monomers based molecularly imprinted polymer Abstract Nowadays, a large number of environmental pollutants (antibiotics, herbicidses, pesticides, et al) are wide used in the process of the food cultivation, production and preservation. In order to detect the trace compounds from complex matrix, determination methods with low sensitivity and high selectivity remains to be a challenge. In our work, molecular-imprinted polymer sensors were given fluorescent-responsive feature for rapid and direct sensing of these trace pollutants. Two novel fluorescent compounds, 2-acrylamide-6-methoxybenzothiazole and 7-acryloxy-4-methylcoumarin were synthesized via a simple one-step reactions, using as both fluorescent reporter and functional monomer to prepare molecular imprinted polymers for detecting alachlor and sulfadiazine respectively. Schematic illustration of the process used to prepare the alachlor-imprinted polymer was shown as a representative in Fig. 1. A particular MIP can specially bind the target analyte, producing changes in the fluorescence of the sensor (either quenching or enhancing), with the degree of change correlating exactly to the concentration of the target analytes. In this manner, binding events on MIPs can be converted into physically detectable fluorescence signals, and analytes can therefore be measured directly without any additional treatment or tests. In this way, and the environmental pollutants could therefore be quantified by converting the physically detectable fluorescence signals. Binding experiments demonstrated that the fluorescence intensity of the resultant polymer decreased linearly with increases in the concentration of alachlor in the range of 1–150 μM (Fig. 2) with a detection limit of 0.43 μM and sulfadiazine in the range 1–40 μM with a detection limit of 0.46 μM respectively. In addition, the fluorescent sensor exhibited significant selectivity over their potentially competitive molecules. Finally, the proposed method was successfully applied for the determination of alachlor in corn seed samples with excellent recoveries ranging from 95.58% to 103.83% (Table 1) and sulfadiazine in milk samples with excellent recoveries ranging from with excellent recoveries ranging from 85.73% to 102.11%. The developed method shows that fluorescent MIPs are expected to be excellent chemosensory materials for the rapid detection of environmental pollutants. Fig. 1. Schematic illustration of the process used to prepare the alachlor-imprinted polymer. Fig. 2. Fluorescent spectra for (a) MIPs, and (b) NIPs, with increasing alachlor concentration in the acetonitrile. The inset shows the corresponding Stern–Volmer plots. Table 1. Determination of alachlor in corn seeds. Concentration taken ( nmol g-1) Found (mean, n=3) ( nmol g-1) Recovery % 1 0.96±0.05 96.00±5.00 5 4.81±0.14 96.20±2.80 10 10.34±0.33 103.40±3.30 30 29.98±0.07 99.93±0.23 60 57.35±0.47 95.58±0.78 90 93.45±0.91 103.83±1.01