Comparison of three cyclodextrins to optimize bisphenol A extraction from source water: Computational, spectroscopic, and analytical studies.

Computationally and spectroscopically assisted analytical comparative investigation into the extraction of bisphenol A using three cyclodextrins, that is, α, ß, and γ respectively, were performed. A simple, self-tailored µ-solid-phase extraction podium was used to extract bisphenol A from water samples, and high-performance liquid chromatography-ultraviolet was used for the qualitative and quantitative analysis of bisphenol A. Density functional theory first principle calculations, attenuated total reflectance Fourier-transform infrared spectroscopy and Fourier-transform Raman spectroscopy data supports the analytical selection of ß-cyclodextrin as the adsorbent for bisphenol A extraction. Analytical optimization of various parameters including sample volume, sample pH, eluting solvent and its volume was performed to discover the most proper conditions for maximum extraction. Under the optimized conditions, a limit of detection value of 0.70 ng/ml and a limit of quantification value of 2.31 ng/ml was achieved with ß-cyclodextrin, with recovery (%) values over 98.40-102.50 in real source water samples. Overall, well assisted by comprehensive computational and spectroscopic studies, a novel, simple, sensitive and economic analytical method was developed for the extraction of bisphenol A from source water using cyclodextrin.

Solid phase extraction with rotating cigarette filter for determination of bisphenol A in source and drinking water: computational and analytical studies.

An ultrasound assisted solid phase extraction method using rotating cigarette filter is developed herein to preconcentrate and determine trace amount of bisphenol in source and drinking water. Qualitative and quantitative measurements were performed using high-performance liquid chromatography coupled with ultra violet detector. Sorbent-analyte interactions were thoroughly investigated computationally and experimentally using molecular dynamics simulations; and attenuated total reflectance Fourier transform infrared spectroscopy, and Raman spectroscopy, respectively. Various extraction parameters were investigated and optimized. Under the optimal conditions, the results were linear in a low scale range of 0.01-55 ng/mL with correlation coefficient of 0.9941 and a low limit of detection (0.04 ng/mL, signal/noise = 3:1). A good precision (intra-day relative standard deviation ≤ 6.05%, inter-day relative standard deviation ≤ 7.12%) and recovery (intra-day ≥ 98.41%, inter-day ≥ 98.04%)) are obtained. Finally, the proposed solid phase extraction method offered a low cost, simple, fast, and sensitive analytical method to determine trace amount of bisphenol A in source and drinking water samples with chromatographic detection.

A novel hybrid micro extraction for the sensitive determination of 17ß-estradiol in water samples.

A novel and green hybrid of pipette tip micro solid-phase extraction (PT-µSPE) and supported liquid extraction (SLE) was tailored and established for efficient and sensitive determination of 17ß-estradiol (E2) in water samples. The hybrid design used chitin as a solid phase in PT-µSPE and applies the SLE principle on it for micro extraction. The analytical setup was termed as chitin-supported pipette tip-micro liquid extraction (CPT-µLE). E2 is a highly active environmental endocrine disruptor, widely spread in the water environment, and thus it is relevant to develop a novel and noble method for its monitoring at trace concentrations in water. The detection and quantification of E2 were performed via HPLC-UV. Under the optimal conditions, E2 showed excellent linearity in the lower scale range of 0.02-20 ng mL-1, and the correlation coefficient (R2) value was 0.9958. The limit of quantitation (LOQ) and limit of detection (LOD) were 0.01 ng mL-1 and 0.008 ng mL-1, respectively, with inter-day and intra-day precision in the range of 3.2-5.1% and 3.6-4.8%, respectively. The method was successfully applied for the sensitive determination of E2 in real water samples. Overall, the method is simple, rapid, technically innovative, cost-effective, highly sensitive, environment friendly, and highly efficient. Furthermore, this method should allow easy expansion to pharmaceutical and biological samples. Finally, this novel hybrid analytical approach proposes a new direction in sample pre-treatment advancements and should act as a reference for other noble analytical advancements in the trace analysis of various emerging contaminants in environmental and biological matrices.

Micelle enhanced and terbium sensitized spectrofluorimetric determination of danofloxacin in milk using molecularly imprinted solid phase extraction.

An efficient molecularly imprinted solid phase extraction (MISPE)-spectrofluorimetric method was developed to sensitively determine danofloxacin (DAN) in milk samples. Solid phase extraction procedure using MISPE cartridges was first performed on milk samples and then spectrofluorimetric determination was done at 546 nm using an excitation wavelength of 285 nm in presence of terbium and sodium dodecyl benzene sulfonate (SDBS). It was found that SDBS significantly enhanced the fluorescence intensity of the DAN-Tb(3+) complex. Various factors affecting the fluorescence intensity of DAN-Tb(3+)-SDBS system were studied and conditions were optimized. The enhanced fluorescence intensity of the system (ΔF) showed a good linear relationship with the concentration of DAN over the range of 8.4×10(-9)-3.4×10(-7) mol L(-1) with a correlation coefficient of 0.9996. The detection limit was determined as 2.0×10(-9) mol L(-1) and the limit of quantification was determined as 6.5×10(-9) mol L(-1). The MISPE-spectrofluorimetric procedure was successfully applied to the determination of DAN in milk samples. The method is simple, rapid, sensitive and allows interference free determination of DAN in complex fluorescent matrices like milk. The method can be used to determine whether the DAN residues in milk exceed MRLs or not.