Design of fluorescent self-assembled multilayers and interfacial sensing for organophosphorus pesticides

doi:10.1016/j.talanta.2008.04.020

Talanta

Volume 76, Issue 4, 15 August 2008, Pages 747-751

https://doi.org/10.1016/j.talanta.2008.04.020 Get rights and content

Abstract

This paper details the fabrication of indole (ID) self-assembled multilayers (SAMs) and fluorescence interfacial sensing for organophosphorus (OP) pesticides. Quartz/APES/AuNP/l-Cys/ID film was constructed on l-cysteine modified Quartz/APES/AuNP surface via electrostatic attraction between ID and l-cysteine. Cyclic voltammetry indicates that ID is immobilized successfully on the gold surface. Fluorescence of the Quartz/APES/AuNP/l-Cys/ID film shows sensitive response toward OPs. The fluorescent sensing conditions of the SAMs are optimized that allow linear fluorescence response for methylparathion and monocrotophos over 5.97 × 10⁻⁷ to 3.51 × 10⁻⁶ g L⁻¹ and 3.98 × 10⁻⁶ to 3.47 × 10⁻⁵ g L⁻¹, with detection limit of 6.1 × 10⁻⁸ gL⁻¹ and 3.28 × 10⁻⁶ gL⁻¹, respectively. Compared to bulk phase detection, interfacial fluorescence sensing based on the SAMs technology shows higher sensitivity by at least 2 order of magnitude.

Introduction

Since organochlorine pesticides were banned using in agriculture, organophosphorus (OP) derivatives started to find worldwide use in insecticides and pesticides [1]. Organophosphorus compounds are structurally similar to nerve gases and act as neurotoxins by inhibiting the enzyme acetylcholinesterase that is responsible for transmitting nerve impulses across synapses [2], [3], [4]. Because of their acute toxicity, rapid detection of OPs in food and ground water has become increasingly demanding for human security and health protection [5]. Traditional analytical methods such as chromatography [6], [7] and electrochemical analysis [8] have been devised to detect OPs. These methods have proven to be sensitive and reliable but with significant disadvantages either. For example, they are time-consuming and expensive and can be carried out only by well-trained personnel. Self-assembled multilayers (SAMs) are stable with ordered structure, and easy to be prepared by a simple adsorption from dilute solutions. With the mediation of cysteine, some extremely sensitive fluorescent sensors based on SAMs have been explored in our previous work [9], [10], [11]. We report here our attempts in employing molecular SAMs based on gold nanoparticle technology to speed up detection of OPs and further improve analytical sensitivity. Gold nanoparticles were first adsorbed on trialkoxysilane-treated quartz surfaces, onto which l-cysteine (l-Cys) was assembled to form the SAMs. The SAMs were subsequently assembled with indole (ID) via its electrostatic interaction with l-cysteine. The prepared multilayers Quartz/APES/AuNP/l-Cys/ID were applied for detection of OPs, with capacity of easy regeneration and higher sensitivity.

Section snippets

Reagents

APES was obtained from Shanghai Chemicals Co. Ltd., indole was purchased from China Guoyao Group, and OPs were received from the Environmental Protection and Monitoring Bureau of the Ministry of Agriculture of China.

All chemicals were of analytical grade or above. Aqueous solutions were prepared using ultrapure water from a Millipore Milli-Q water purification system (18 MΩ cm).

Instruments

Electrochemical measurements were carried out on a BAS-100B electrochemical analyzer with a conventional three-electrode

Reaction mechanism

Previously it was reported that some amines could be oxidized by OPs in the presence of SPB into fluorescent products [13]. Fig. 1, Fig. 2 show that the reaction proceeds in two steps, the nucleophilic substitution of OPs by OOH⁻ (SPB) into peroxide phosphate acid and indole oxidation into indoxyl by the peroxide phosphate acid [14], [15].

Fluorescence properties of indoxyl

In bulk aqueous solution SPB and ID are nonfluorescent [16], [17]. In the presence methylparathion, the assumed product indoxyl emitted fluorescence at 525 nm

Conclusions

Fluorescent assembly of Quartz/APES/AuNP/l-Cys/ID was successfully prepared by chemisorption on the quartz wafer and was shown to be a convenient and supplemental analytical tool for monitoring organophosphorus pesticides in environmental and agricultural samples. The developed SAMs integrated with fluorescence analysis technology were capable of detecting as low as 10⁻⁶ g L⁻¹ of monocrotophos and 10⁻⁸ g L⁻¹ of methylparathion. Fabrication was shown to be simple and fast with the SAMs being of good

Acknowledgements

This work was supported by the National Natural Science Foundation of China (grant no. 20575023), Natural Science Foundation of Fujian Province, China (grant no. D0710017), International Cooperative Foundation of Fujian Province (grant no. 2006I0021), and Overseas Chinese Affairs Office of the State Council of China (grant no. 06QZR10).

References (18)

S. Zhang et al.
Biosens. Bioelectron.
(2001)
S. Fennouh et al.
Biosens. Bioelectron.
(1997)
C. Cremisini et al.
Anal. Chim. Acta.
(1995)
I. Palchetti et al.
Anal. Chim. Acta
(1997)
X.-Y. Sun et al.
Talanta
(2004)
X.-Y. Sun et al.
Anal. Chim. Acta
(2004)
D. Munnecke
J. Agric. Food Chem.
(1980)
J.A. Compton
Military Chemical and Biological Agents
(1988)
C.E. Mendoza
Thin-layer chromatography

There are more references available in the full text version of this article.

Cited by (25)

Advances in gold nanoparticles for optical detection of nerve agents
2022, Sensing of Deadly Toxic Chemical Warfare Agents, Nerve Agent Simulants, and their Toxicological Aspects
Gold nanoparticles (AuNPs) have been used as colorimetric and fluorescence detection tools for chemical warfare agents (CWAs). This chapter presents a selective and comprehensive overview on the sensing of nerve agents as well as other CWAs such as vesicant, cytotoxic proteins, and pulmonary. The sensing techniques depend on the surface Plasmon resonance mechanism as well as physicochemical characteristics of properly functionalized AuNPs. An overview of the major colorimetric and fluorescence AuNPs-based materials is discussed to reveal their progress and importance through ongoing research of CWAs sensors. The current chapter wraps up with the future trends on the developments of sensors for CWAs from AuNPs-based materials with improved performance.
G-quadruplex formation enhancing energy transfer in self-assembled multilayers and fluorescence recognize for Pb<sup>2+</sup> ions
2018, Sensors and Actuators, B: Chemical
Here we demonstrate a novel strategy for the detection of Pb²⁺ ions and DNA based on the fluorescence resonance energy transfer in the self-assembled multilayers (SAMs). Quartz/GO/PDDA/G5/PDDA/GQDs@GSH SAMs were built by employing graphene oxide (GO) as the energy acceptor, glutathione-functionalized graphene quantum dots (GQDs@GSH) as the energy donor as well as poly(diallydimethylammonium) chloride (PDDA) and G5 (G-rich DNA) strand as the linker. In the presence of a certain amount of Pb²⁺ ions, G5 DNA could be folded into G-quadruplex, which was confirmed by Quartz Crystal Microbalance (QCM) experiments. The formation of G-quadruplex could lead to a change in the chain length and the shortening of the distance between GO and GQDs@GSH, thereby, the efficiency of energy transfer between GQDs@GSH and GO was enhanced with the quenching of fluorescence of GQDs@GSH. Meanwhile, Pb²⁺ ions could be recognized successfully.
Silica nanoparticle based techniques for extraction, detection, and degradation of pesticides
2016, Advances in Colloid and Interface Science
Citation Excerpt :
There are also reports on the use of SiNPs in developing fluorescence dependent methodologies for detecting pesticides. An indole (ID) based sensor has been fabricated for detecting organophosphate pesticides [95]. ID in bulk aqueous solutions is non-fluorescent.
Silica nanoparticles (SiNPs) find applications in the fields of drug delivery, catalysis, immobilization and sensing. Their synthesis can be mediated in a facile manner and they display broad range compatibility and stability. Their existence in the form of spheres, wires and sheets renders them suitable for varied purposes. This review summarizes the use of silica nanostructures in developing techniques for extraction, detection and degradation of pesticides. Silica nanostructures on account of their sorbent properties, porous nature and increased surface area allow effective extraction of pesticides. They can be modified (with ionic liquids, silanes or amines), coated with molecularly imprinted polymers or magnetized to improve the extraction of pesticides. Moreover, they can be altered to increase their sensitivity and stability. In addition to the analysis of pesticides by sophisticated techniques such as High Performance Liquid Chromatography or Gas chromatography, silica nanoparticles related simple detection methods are also proving to be effective. Electrochemical and optical detection based on enzymes (acetylcholinesterase and organophosphate hydrolase) or antibodies have been developed. Pesticide sensors dependent on fluorescence, chemiluminescence or Surface Enhanced Raman Spectroscopic responses are also SiNP based. Moreover, degradative enzymes (organophosphate hydrolases, carboxyesterases and laccases) and bacterial cells that produce recombinant enzymes have been immobilized on SiNPs for mediating pesticide degradation. After immobilization, these systems show increased stability and improved degradation. SiNP are significant in developing systems for effective extraction, detection and degradation of pesticides. SiNPs on account of their chemically inert nature and amenability to surface modifications makes them popular tools for fabricating devices for ‘on-site’ applications.
Reusable fluorescent sensor for captopril based on energy transfer from photoluminescent graphene oxide self-assembly multilayers to silver nanoparticles
2016, Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy
Citation Excerpt :
3) By integrating of functional groups into SAMs, sensing selectivity can be substantially improved. Therefore, developing SAMs based on PL intensity change can demonstrate broad applications for chemicals and biomolecules, our group have designed fluorescent SAMs, which were applied for highly sensitive chemo- and bio-sensor with regeneration [14–16]. In this work, we first synthesized graphene oxide modified by butylamine (GO-NHBu), subsequently constructed photoluminescent GO-NHBu SAMs.
In this work we designed a self-assembly multilayers, in which photoluminescent graphene oxide was employed as a fluorescence probe. This multilayers film can effectively recognize captopril by resonance energy transfer from graphite oxide to silver nanoparticles. A new interfacial sensing method for captopril with high signal to noise ratio was established, by means of that multilayers was quenched by silver nanoparticles and subsequently recovered by adding captopril. The linear relation between intensity and captopril concentration was good, and the detection limit was found to be 0.1578 μM. Also, this novel detection platform demonstrated intriguing reusable properties, and the sensor could be repeated more than ten times without obviously losing its sensing performance.
Gold nanoparticles as sensors in the colorimetric and fluorescence detection of chemical warfare agents
2016, Coordination Chemistry Reviews
A short overview of colorimetric and fluorescence detection with gold nanoparticle (AuNP) sensors of chemical warfare agents (CWAs) is provided. This review of CWA sensing includes nerve agents, vesicant agents, pulmonary agents, cytotoxic proteins, suffocating/blood agents, incapacitating agents, and lachrymatory. The sensing methods are based on the optical (surface plasmon band) and other physico-chemical properties of appropriately functionalized AuNPs.
DNA-length-dependent fluorescent sensing based on energy transfer in self-assembled multilayers
2014, Biosensors and Bioelectronics
In this paper, a novel DNA-length-dependent fluorescent sensor was constructed based on the fluorescence resonance energy transfer. In the self-assembled multilayers (Quartz/GO/PDDA/T_x-DNA/PDDA/ZnO@CdS), ZnO@CdS and graphene oxide(GO) were employed as an energy donor and an energy acceptor, respectively. Single-stranded T_x-DNA (x represents different chain length of DNA) and poly(diallydimethylammonium) chloride (PDDA) were used as a linker. In the presence of complementary P_x-DNA, the formation of double-stranded DNA leads to a change in chain length and achieves the purpose of changing the distance between ZnO@CdS and GO. Thereby, it enhances the efficiency of energy transfer between ZnO@CdS and GO resulting in the quench of fluorescence of ZnO@CdS, and thus different length DNA sequence was detected.

View all citing articles on Scopus

View full text

Design of fluorescent self-assembled multilayers and interfacial sensing for organophosphorus pesticides

Abstract

Introduction

Section snippets

Reagents

Instruments

Reaction mechanism

Fluorescence properties of indoxyl

Conclusions

Acknowledgements

Biosens. Bioelectron.

Biosens. Bioelectron.

Anal. Chim. Acta.

Anal. Chim. Acta

Talanta

Anal. Chim. Acta

J. Agric. Food Chem.

Military Chemical and Biological Agents

Thin-layer chromatography