Solubilization of organics I: ¹H NMR chemical shift perturbations, diffusometry, and NOESY indicate biphenyls internalize in micelles formed by cetyltrimethylammonium bromide

Abstract

Polychlorinated biphenyls are a class of persistent environmental contaminants, and micellar solubilization can be applied to remediate them. The intermolecular aggregates of biphenyl (BP) analogs and cetyltrimethyl ammonium bromide (CTAB) were studied by chemical shift perturbation, nuclear magnetic resonance (NMR) diffusometry, quantitative proton NMR, and nuclear Overhauser effect (NOE) spectroscopy to understand the structural determinants of their solubilization. The micelles of CTAB solubilized BPs readily, but its capacity depended strongly on the nature of the functional group (BPCH 2 OH > > BPCHO > BPCOOH ≈ BPCl ≈ BP). Upon internalization, the BPs diffused much slower, introduced significant low-frequency 1 H chemical shift changes for CTAB, and displayed strong intermolecular NOEs. The semiquantitative analysis of NOEs revealed further that the BPs are located in the palisade layer closer to the N + (CH 3 ) 3 head group, away from the hydrophobic core. 1 H NMR offers a simple high-throughput screening assay for evaluating and quantitating the solubilization of organics in micelles. The intermolecular NOEs and site-specific perturbation of chemical shifts add further insights on the location of solubilizates in micelles, which may be important for designing surfactants specific for environmental pollutants.

How to write a research article for MRC

“…Examples of these different formats can be found throughout the pages of MRC, for example, IMRaD see Peroza, et al, Joubert, et al, and Araújo, et al. [19][20][21] IRDaM see Blechta and Sýkora, Lomas, and Dewis, et al [22][23][24]…”

“…As with Results and Discussion in the IMRaD structure, this section in an IRDaM format again constitutes the largest and most challenging portion of the article to compose. Examples of these different formats can be found throughout the pages of MRC , for example, IMRaD see Peroza, et al ., Joubert, et al ., and Araújo, et al . IRDaM see Blechta and Sýkora, Lomas, and Dewis, et al …”

Imidazolium Triflate Ionic Liquids’ Capacitance–Potential Relationships and Transport Properties Affected by Cation Chain Lengths

“…All the measurements are performed at 25 and 60 °C unless mentioned otherwise, and samples are thermally equilibrated at the stated temperature for 15 min before the data collection. All the diffusion measurements are made using the stimulated echo pulse sequence with bipolar gradient pulses. , The diffusion delay (Δ) is varied from 20 to 50 ms, and the gradient pulse duration (δ) is varied from 1.5 to 5 ms. Both Δ and δ are optimized to obtain 1–5% residual signal at 95% of the maximum gradient strength.…”

“…All the diffusion measurements are made using the stimulated echo pulse sequence with bipolar gradient pulses. 59,60 The diffusion delay (Δ) is varied from 20 to 50 ms, and the gradient pulse duration (δ) is varied from 1.5 to 5 ms. Both Δ and δ are optimized to obtain 1−5% residual signal at 95% of the maximum gradient strength.…”