MyMedR

Displaying all 4 publications

Abstract:

Sort:

A simultaneous derivatization of 3-monochloropropanediol and 1,3-dichloropropane with hexamethyldisilazane-trimethylsilyl trifluoromethanesulfonate at room temperature for efficient analysis of food sample analysis

Lee BQ, Wan Mohamed Radzi CW, Khor SM

J Chromatogr A, 2016 Feb 5;1432:101-10.
PMID: 26792449 DOI: 10.1016/j.chroma.2015.12.087

This paper reports the application of hexamethyldisilazane-trimethylsilyl trifluoromethanesulfonate (HMDS-TMSOTf) for the simultaneous silylation of 3-monochloro-1,2-propanediol (3-MCPD) and 1,3-dicholoropropanol (1,3-DCP) in solid and liquid food samples. 3-MCPD and 1,3-DCP are chloropropanols that have been established as Group 2B carcinogens in clinical testing. They can be found in heat-processed food, especially when an extended high-temperature treatment is required. However, the current AOAC detection method is time-consuming and expensive. Thus, HMDS-TMSOTf was used in this study to provide a safer, and cost-effective alternative to the HFBI method. Three important steps are involved in the quantification of 3-MCPD and 1,3-DCP: extraction, derivatization and quantification. The optimization of the derivatization process, which involved focusing on the catalyst volume, derivatization temperature, and derivatization time was performed based on the findings obtained from both the Box-Behnken modeling and a real experimental set up. With the optimized conditions, the newly developed method was used for actual food sample quantification and the results were compared with those obtained via the standard AOAC method. The developed method required less samples and reagents but it could be used to achieve lower limits of quantification (0.0043mgL(-1) for 1,3-DCP and 0.0011mgL(-1) for 3-MCPD) and detection (0.0028mgL(-1) for 1,3-DCP and 0.0008mgL(-1) for 3-MCPD). All the detected concentrations are below the maximum tolerable limit of 0.02mgL(-1). The percentage of recovery obtained from food sample analysis was between 83% and 96%. The new procedure was validated with the AOAC method and showed a comparable performance. The HMDS-TMSOTf derivatization strategy is capable of simultaneously derivatizing 1,3-DCP and 3-MCPD at room temperature, and it also serves as a rapid, sensitive, and accurate analytical method for food samples analysis.

Matched MeSH terms: Organosilicon Compounds
Enhanced water flux and bacterial resistance in cellulose acetate membranes with quaternary ammoniumpropylated polysilsesquioxane

Pandey RP, Kallem P, Rasheed PA, Mahmoud KA, Banat F, Lau WJ, et al.

Chemosphere, 2022 Feb;289:133144.
PMID: 34863730 DOI: 10.1016/j.chemosphere.2021.133144

An enhanced water flux and anti-fouling nanocomposite ultrafiltration membrane based on quaternary ammoniumpropylated polysilsesquioxane (QAPS)/cellulose acetate (QAPS@CA) was fabricated by in situ sol-gel processing via phase inversion followed by quaternization with methyl iodide (CH3I). Membrane characterizations were performed based on the contact angle, FTIR, SEM, and TGA properties. Membrane separation performance was assessed in terms of pure water flux, rejection, and fouling resistance. The 7%QAPS@CA nanocomposite membrane showed an increased wettability (46.6° water contact angle), water uptake (113%) and a high pure water permeability of ∼370 L m-2 h-1 bar-1. Furthermore, the 7%QAPS@CA nanocomposite membrane exhibited excellent bactericidal properties (∼97.5% growth inhibition) against Escherichia coli (E. coli) compared to the bare CA membrane (0% growth inhibition). The 7%QAPS@CA nanocomposite membrane can be recommended for water treatment and biomedical applications.

Matched MeSH terms: Organosilicon Compounds
Fulltext Investigation of CPD and HMDS sample preparation techniques for cervical cells in developing computer-aided screening system based on FE-SEM/EDX

Jusman Y, Ng SC, Abu Osman NA

ScientificWorldJournal, 2014;2014:289817.
PMID: 25610902 DOI: 10.1155/2014/289817

This paper investigated the effects of critical-point drying (CPD) and hexamethyldisilazane (HMDS) sample preparation techniques for cervical cells on field emission scanning electron microscopy and energy dispersive X-ray (FE-SEM/EDX). We investigated the visualization of cervical cell image and elemental distribution on the cervical cell for two techniques of sample preparation. Using FE-SEM/EDX, the cervical cell images are captured and the cell element compositions are extracted for both sample preparation techniques. Cervical cell image quality, elemental composition, and processing time are considered for comparison of performances. Qualitatively, FE-SEM image based on HMDS preparation technique has better image quality than CPD technique in terms of degree of spread cell on the specimen and morphologic signs of cell deteriorations (i.e., existence of plate and pellet drying artifacts and membrane blebs). Quantitatively, with mapping and line scanning EDX analysis, carbon and oxygen element compositions in HMDS technique were higher than the CPD technique in terms of weight percentages. The HMDS technique has shorter processing time than the CPD technique. The results indicate that FE-SEM imaging, elemental composition, and processing time for sample preparation with the HMDS technique were better than CPD technique for cervical cell preparation technique for developing computer-aided screening system.

Matched MeSH terms: Organosilicon Compounds/chemistry
Fulltext Antimicrobial quaternary ammonium organosilane cross-linked nanofibrous collagen scaffolds for tissue engineering

Dhand C, Balakrishnan Y, Ong ST, Dwivedi N, Venugopal JR, Harini S, et al.

Int J Nanomedicine, 2018;13:4473-4492.
PMID: 30122921 DOI: 10.2147/IJN.S159770

Introduction: In search for cross-linkers with multifunctional characteristics, the present work investigated the utility of quaternary ammonium organosilane (QOS) as a potential cross-linker for electrospun collagen nanofibers. We hypothesized that the quaternary ammonium ions improve the electrospinnability by reducing the surface tension and confer antimicrobial properties, while the formation of siloxane after alkaline hydrolysis could cross-link collagen and stimulate cell proliferation.
Materials and methods: QOS collagen nanofibers were electrospun by incorporating various concentrations of QOS (0.1%-10% w/w) and were cross-linked in situ after exposure to ammonium carbonate. The QOS cross-linked scaffolds were characterized and their biological properties were evaluated in terms of their biocompatibility, cellular adhesion and metabolic activity for primary human dermal fibroblasts and human fetal osteoblasts.
Results and discussion: The study revealed that 1) QOS cross-linking increased the flexibility of otherwise rigid collagen nanofibers and improved the thermal stability; 2) QOS cross-linked mats displayed potent antibacterial activity and 3) the biocompatibility of the composite mats depended on the amount of QOS present in dope solution - at low QOS concentrations (0.1% w/w), the mats promoted mammalian cell proliferation and growth, whereas at higher QOS concentrations, cytotoxic effect was observed.
Conclusion: This study demonstrates that QOS cross-linked mats possess anti-infective properties and confer niches for cellular growth and proliferation, thus offering a useful approach, which is important for hard and soft tissue engineering and regenerative medicine.

Matched MeSH terms: Organosilicon Compounds/pharmacology*