Fluorescent Molecular Recognition for Endocrine-Disrupting Chemicals and Their Analogs by Fluorescent Hetero-Modified Cyclodextrins

Abstract

The detection of endocrine-disrupting chemicals required high technology, such as an analysis by GC/MS, which is very costly, and the analytical results require many days to obtain. [1][2][3][4][5][6][7][8] However, it is urgent to quickly and conveniently confirm the existence of endocrine-disrupting chemicals in rivers and lakes. In a previous paper, we discussed the first example of fluorescent molecular sensing for endocrine-disrupting chemicals and dioxin analogs by homo fluorescent β-and γ -cyclodextrins, which were modified with bis fluorescent-active units such as dansyl or anthranilate. 9 In the present study, endocrine-disrupting chemicals, including p-nonylphenol and bisphenol A, and a dioxin analog, such as 2,4,6-trichlorophenol, were conveniently and directly detected by these fluorescent cyclodexstrins with high sensitivity and selectivity; pattern recognition of endocrinedisrupting chemicals would be expected to be possible. Furthermore, it was obvious that bis anthranilate-modified β-cyclodextrins can detect 10 -6 M of p-nonylphenol. We have previously discussed the synthesis of regioselectively fluorescent hetero-substituted cyclodextrins, which are 6 A -dansyl-6 X -tosylmodified β-cyclodextrins (X=B or G, C or F, and D or E) and 6 A -dansyl-6 X -tosyl-modified γ -analogs (X=B or H, C or G, D or F, and E), and examined of their fluorescent molecular-sensing abilities for organic compounds, such as bile acids and terpenes. 10 In this system, these hosts exhibited higher sensitive and selective molecular recognition ability for ursodeoxycholic acid, chenodeoxycholic acid and (-)-borneol compared to monoand di-dansyl-modified β-and γ -analogs, which were reported previously. [11][12][13][14] As a further extension of our work, we investigated the fluorescence spectral changes of the titled hosts, fluorescent hetero-modified cyclodextrins, concerning the accommodation of endocrine-disrupting chemicals. In this paper, we wish to describe the fluorescent-sensing abilities of these host compounds for environmental hormones. These hetero-modified hosts detect bisphenol A and 2,4,6-trichlorophenol with high sensitivity and selectivity. ExperimentalPreparations of β-1, β-2, β-3, γ -1, γ -2, γ -3, and γ -4The host compounds (β -1, β-2, β-3, γ -1, γ -2, γ -3, and γ -4) were prepared according to previously reported procedures. 10 MeasurementsThe fluorescence spectra were measured at 25˚C with a Perkin Elmer LS 40B fluorescence spectrometer. In fluorescence measurements, the excitation wavelength of the fluorescence spectra was 340 nm and the excitation and emission slits were 10 nm. An ethylene glycol aqueous solution (10 vol.%) was used as the solvent for hosts for spectroscopic measurements, because their solubility in pure water is poor. Five microliters of guest species (500, 50 and 5 mM) in dimethyl sulfoxide (DMSO) or MeOH were injected into a 10 vol.% ethylene glycol aqueous solution of the host (2.5 mL) to make a sample solution with a host concentration of 1×10 -6 M and guest concentrations of 0.0...

Fluorescent Molecular Sensory System Based on Bis Pyrene-Modified γ-Cyclodextrin Dimer for Steroids and Endocrine Disruptors

“…2,4,6-Trichlorophenol was detected by host 1 at excimer emission with response range of 10 -5.5 -10 -3 M and at monomer emissions with response ranges of above 10 -4 M. The response range of host 1 for 2,4,6-trichlorophenol at excimer emission started at a lower concentration than those of host 1 for this guest at monomer emissions. Additionally, the lower detection limit of host 1 at excimer emission for this guest is lower than those of fluorescent homo-or hetero-modified CyDs reported previously 24,25 at monomer emission. It is recognized that this fluorescent dimer detects 2,4,6-trichlorophenol at excimer emission with much more remarkable selectivity.…”

“…Previously, we have found that our CyD derivatives can detect endocrine disruptors with high sensitivity and selectivity. 24,25 That is why we have tried again to study the fluorescent binding ability for bile acids in addition to endocrine disruptors by the titled CyD dimer.…”

Selective Recognition of Endocrine Disruptors by Fluorogenic γ-Cyclodextrin Having Pyrene-Tosyl Substituents on Hetero Rims

“…[20][21][22][23] Therefore, it would be interesting to design a molecular sensory system of a new fluorescent CyD labeled at both the upper and lower rims. Previously, we found that our fluorescent CyD derivatives can detect endocrine disruptors with high sensitivity and selectivity, 24,25 in which heteroappended CyDs could more sensitively recognize endocrine disruptors than homo-appended CyDs. This is why we have again tried to study the fluorescent binding ability of endocrine disruptors using the titled CyD compound.…”

Sorption/Desorption of Polychlorinated Dibenzo-P-Dioxins and Polychlorinated Dibenzo Furans (PCDDs/PCDFs) in the Presence of Cyclodextrins

“…Narita et al (2000) studied fluorescent molecular sensing for endocrine-disrupting chemicals (including PCDDs/PCDFs) and their analogs using regio-selective dansyl-tosyl-modified β-cyclodextrin (BCD) and γ-cyclodextrin (GCD) and found that these host compounds showed pure monomer fluorescence at 526 nm; the intensities of the guest-induced fluorescence either increased or decreased depending on PCDD/PCDF analogs. Otsuka et al (1999) carried out an on-line concentration of neutral analytes for CD assisted micellar electrokinetic chromatography (MEKC) in environmental analysis to enhance the UV detection sensitivity using several PCDD/PCDF compounds and found that the detection sensitivity increased 200 times.…”