Papers by 191-04 nadia Sultana
Physical Chemistry Chemical Physics, 2021
Twenty dyes from the Max Weaver Dye Library were used to benchmark six commonly used DFT function... more Twenty dyes from the Max Weaver Dye Library were used to benchmark six commonly used DFT functionals to understand the interplay between the errors in the calculated excitation energies and the degree of charge transfer character of the excitations.
Analytical Methods, 2020
In this study, reactive dye degradation products after landfilling were extracted by a modified Q... more In this study, reactive dye degradation products after landfilling were extracted by a modified QuEChERS extraction method and detected by high-resolution QTOF mass spectrometry.
Coloration Technology, 2019
When textile substrates biodegrade in landfills, the fate of textile colorants is unknown, and po... more When textile substrates biodegrade in landfills, the fate of textile colorants is unknown, and potentially poses an ecotoxic threat. In this study, we developed a systematic analytical method to evaluate the biodegradation of reactive dyes, the most common class of dye applied to cotton fabrics. The cotton fabrics were dyed with CI Reactive Blue 19 and biodegraded in soil in a laboratory-controlled environment over intervals of 45 and 90 days. A dye isolation method using a low concentration of alkali (0.15% sodium hydroxide) was developed and applied (80°C for 1 hour) to isolate intact and degraded dye from the fabric samples. To quantify the intact dye isolated from the fabric samples, a quantification method was then developed using liquid chromatography-photodiode array detection. The quantification method provided excellent linearity (R 2 = 0.9997 ± 0.0002), accuracy (% error = −2% ± 4), precision (% coefficient of variation = 2% ± 4) and sensitivity (lower limit of quantification = 0.4 ± 0.2 µg/mL) for concentrations ranging from 1 to 50 µg/mL. After validation, the method was applied and showed a reduction of dye in biodegraded samples (after 45 and 90 days) compared with undegraded control samples (0 days). To characterise the isolated dye degradation product, quadrupole time-of-flight tandem mass spectrometry was utilised. Analysis showed that the degradation product was formed by losing a −SO 3 − group from the intact hydrolysed form of the dye, creating a more hydrophobic degradation product compared with the intact hydrolysed form of dye.
Forensic Science International, 2018
Textile fiber is a common form of transferable trace evidence at the crime scene. Different techn... more Textile fiber is a common form of transferable trace evidence at the crime scene. Different techniques such as microscopy or spectroscopy are currently being used for trace fiber analysis. Dye characterization in trace fiber adds an important molecular specificity during the analysis. In this study, we performed a direct trace fiber analysis method via dye characterization by a novel automated microfluidics device (MFD) dye extraction system coupled with a quadrupole-time-of-flight (Q-TOF) mass spectrometer (MS). The MFD system used an in-house made automated procedure which requires only 10 mL of organic solvent for the extraction. The total extraction and identification time by the system is under 12 min. A variety of sulfonated azo and anthraquinone dyes were analyzed from $1 mm length nylon fiber samples. This methodology successfully characterized multiple dyes (!3 dyes) from a single fiber thread. Additionally, it was possible to do dye characterization from single fibers with a diameter of $10 mm. The MFD-MS system was used for elemental composition and isotopic distribution analysis where MFD-MS/ MS was used for structural characterization of dyes on fibers.
Coloration Technology, 2018
As part of an approach to enhancing the efficiency of reactive dye adsorption on cellulosic fibre... more As part of an approach to enhancing the efficiency of reactive dye adsorption on cellulosic fibres at low electrolyte levels, commercially available dyes were dimerised using hexamethylenediamine (HMDA) as a linking group. A key component of this work involved using high-resolution mass spectrometry (HRMS) to characterise a group of polysulphonated heterobifunctional monochlorotriazine/vinyl sulphone reactive dyes (CI Reactive Yellow 176, CI Reactive Red 239, CI Reactive Blue 221, CI Reactive Red 194 and CI Reactive Blue 222) and their dimeric analogs. In this respect, dimeric dye ions of differently charged states were observed using HRMS-negative electrospray ionisation in combination with quadrupole time-of-flight mass spectrometry. For example, HRMS showed that the HMDA-linked reaction products were mixtures of the target (unhydrolysed) dimers, hydrolysed dimers, monoreacted products and hydrolysed unreacted dyes, with CI Reactive Yellow 176 and CI Reactive Red 194 producing the desired unhydrolysed dimers.
Chemical Science, 2017
The Max Weaver Dye Library is presented to the scientific community with a cheminformatics approa... more The Max Weaver Dye Library is presented to the scientific community with a cheminformatics approach to enhance research opportunities with this unique collection of ∼98 000 vials of custom-made dyes.
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Papers by 191-04 nadia Sultana