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A new method for quantification of 12 nitroaromatic compounds including 2,4,6-trinitrotoluene, its metabolites and 2,4,6-trinitrophenyl-N-methylnitramine with microextraction by packed sorbent followed by gas chromatography and mass spectrometric detection in environmental and biological samples is developed. The microextraction device employs 4 mg of C silica sorbent inserted into a microvolume syringe for sample preparation. Several parameters capable of influencing the microextraction procedure, namely, number of extraction cycles, washing solvent, volume of washing solvent, elution solvent, volume of eluting solvent and pH of matrix, were optimized. The developed method produced satisfactory results with excellent values of coefficient of determination (R > 0.9804) within the established calibration range. The extraction yields were satisfactory for all analytes (> 89.32%) for aqueous samples and (> 87.45%) for fluidic biological samples. The limits of detection values lie in the range 14-828 pg/mL.

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A solid-phase microextraction (SPME) method followed by separation with high-performance liquid chromatography and subsequent UV detection was developed for the determination of norfloxacin and enrofloxacin. The simple and sensitive preconcentration technique uses 280 nm wavelength in mobile phase of citrate buffer (0.01 M), pH 3.8, prepared in water (A) and acetonitrile (B), with composition of the mobile phase A:B, 40:60, at a flow rate of 1.0 mL/min. A C18 reversed-phase analytical column (5 m) was selected as separation medium for the technique. To obtain optimum extraction efficiency, several parameters relating to SPME were investigated. The method was linear over the range of 10100 ng/mL for norfloxacin and enrofloxacin with a correlation coefficient (R2) value of 0.9972 and 0.9980 for norfloxacin and enrofloxacin, respectively. Using the SPME method, the detection limits (signal-to-noise ratio 3) are 0.17 and 0.12 ng/mL for norfloxacin and enrofloxacin, respectively.

An amine-decorated zirconium-based metal–organic framework (MOF, coded as UiO-66-NH2) with rod shaped morphology has been solvothermally synthesized using low-cost and easily available 2-aminoterephthalic acid as an organic linker. The crystallinity of the synthesized MOF material has been confirmed by sharp PXRD diffraction pattern. Photoluminescent studies showed that the UiO-66-NH2 features a strong fluorescent behaviour when dispersed in water, which could be used as a highly selective and sensitive sensor for detection of trace amount of 2,4,6-trinitrophenol (TNP), even in coexistence with other potentially competitive nitroaromatic analytes. High value of Stern-Volmer quenching constant Ksv (1.106 x 105 M-1), photoluminescent quenching efficiency (97.8%) and lower detection limit (0.95 μM/217ng mL-1) ascertained extraordinary sensitivity of developed UiO-66-NH2 for TNP. Density functional theory (DFT) calculations and electrostatic interactions (i.e. ionic interaction, H-bonding and π-π interaction) indicated that electron and energy transfer processes play a key role in the turn-off quenching response of UiO-66-NH2 sensor towards TNP.