Organic Compound Analysis

The development of sensors for the detection of organic compounds in the environment and foods has received increasing attention. At present, organic compound analysis of generally requires the use of analytical instruments, which are expensive and complex to operate. Click chemistry provides a simple and efficient way to fabricate chemical sensors for organic compound analysis. For “clickable” organic compounds, click chemistry could be employed directly for organic compound analysis. As for organic compounds that could only produce weak or no signal, in order to improve the sensitivity of chemical sensors, these compounds could be labeled with electroactive compounds or chromophores by click chemistry^[1].

Applications

• In pesticides residue analysis

Click chemistry has attracted wide interest in pesticide residue analysis. A sensitive and selective fluorescent sensor for flumioxazin analysis was designed by Lu and co-workers (Scheme 1). This sensor is based on the formation of a strong fluorescence compound (1,2,3-triazole compound) via the copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) click reaction between an alkynyl group in flumioxazin and 3-azido-7-hydroxycoumarin, a weak-fluorescent compound^[2]. Because of high sensitivity and selectivity, fluorescent sensor has been applied to test flumioxazin residues in some vegetables or water samples and the results are satisfactory. In addition to flumioxazin residues, chlorpyrifos and organophosphorus pesticide residues can also be detected by chemical sensors prepared by click chemistry.

Scheme 1. The principle of fluorescent sensor.

• In hydroquinone analysis

Wang et al^[3]. developed a three-step method to graft molecularly imprinted polymer (MIP) thin films onto Au electrodes for the determination of hydroquinone (HQ). In the first step, propargyl acrylate was clicked onto an azidoundecanethiol/decanethiol mixed self-assembled monolayer. Then, by applying UV light in the presence of N,N′-methylenebis (acrylamide) and azobisisobutyronitrile as the radical initiator, polymerization was directly carried out on the electrode surface in the presence of an electroactive HQ (Scheme 2). Detection of HQ using the clicked-on MIP sensor was studied using chronoamperometry. The sensitivity of the clicked-on MIP sensor was found to be approximately three times greater than of a sensor prepared by drop-coating MIPs onto Au electrodes.

Scheme 2. Preparation of clicked-on MIP sensor by the 'click' reaction
between azidoundecanethiol and propargyl acrylate.

What Can We Do?

Alfa Chemistry has a strong research foundation in the preparation of chemical sensors for organic compound analysis. We have ability to help you explore the various applications of click chemistry and provide you with related click chemistry reagents, technical advice and services. If you have problems, please don't hesitate to contact us.

References

1. Ji, N.; et al. Progress on click chemistry and its application in chemical sensors. Chinese Journal of Analytical Chemistry. 2015, 4 (43): 609-617.
2. Lu, L.; et al. Determination of flumioxazin residue in food samples through a sensitive fluorescent sensor based on click chemistry. Food Chemistry. 2014, 162: 242-246.
3. Wang, T.; Shannon, C. Electrochemical sensors based on molecularly imprinted polymers grafted onto gold electrodes using click chemistry. Analytica Chimica Acta. 2011, 708: 37-43.