Mohammad S. El-Shahawi

Bio: Mohammad S. El-Shahawi is an academic researcher from King Abdulaziz University. The author has contributed to research in topics: Aptamer & Detection limit. The author has an hindex of 24, co-authored 83 publications receiving 2607 citations. Previous affiliations of Mohammad S. El-Shahawi include United Arab Emirates University & Damietta University.

Recent advances in dispersive liquid-liquid microextraction for pesticide analysis

Abstract: Dispersive liquid-liquid microextraction (DLLME) techniques have attracted considerable interest because they are cost effective, easy to operate, and reliably preconcentrate trace levels of analytes in complex matrices. This comprehensive review is concerned with principles, applications and developments of DLLME techniques for analysis of trace emerging pesticides in water. DLLME techniques have had few couplings to spectrofluorimetric methods and relatively none with electrochemical techniques. We highly recommend thin-layer stripping voltammetric techniques at surface-modified electrodes and spectrofluorimetric techniques coupled and implemented with DLLME. Great attention should be focused on developing low-cost, precise methods for analysis of trace concentrations of pesticides in various biological and environmental samples. We describe milestones and the combination of nanotechniques in the DLLME field, green aspects, advantages and shortcomings of known DLLME protocols.

Ultrasensitive, rapid and inexpensive detection of DNA using paper based lateral flow assay.

Abstract: Sensitive, specific, rapid, inexpensive and easy-to-use nucleic acid tests for use at the point-of-need are critical for the emerging field of personalised medicine for which companion diagnostics are essential, as well as for application in low resource settings. Here we report on the development of a point-of-care nucleic acid lateral flow test for the direct detection of isothermally amplified DNA. The recombinase polymerase amplification method is modified slightly to use tailed primers, resulting in an amplicon with a duplex flanked by two single stranded DNA tails. This tailed amplicon facilitates detection via hybridisation to a surface immobilised oligonucleotide capture probe and a gold nanoparticle labelled reporter probe. A detection limit of 1 × 10−11 M (190 amol), equivalent to 8.67 × 105 copies of DNA was achieved, with the entire assay, both amplification and detection, being completed in less than 15 minutes at a constant temperature of 37 °C. The use of the tailed primers obviates the need for hapten labelling and consequent use of capture and reporter antibodies, whilst also avoiding the need for any post-amplification processing for the generation of single stranded DNA, thus presenting an assay that can facilely find application at the point of need.

Environmental Contamination by Heavy Metals

Abstract: The environment and its compartments have been severely polluted by heavy metals. This has compromised the ability of the environment to foster life and render its intrinsic values. Heavy metals are known to be naturally occurring compounds, but anthropogenic activities introduce them in large quantities in different environmental compartments. This leads to the environment's ability to foster life being reduced as human, animal, and plant health become threatened. This occurs due to bioaccumulation in the food chains as a result of the nondegradable state of the heavy metals. Remediation of heavy metals requires special attention to protect soil quality, air quality, water quality, human health, animal health, and all spheres as a collection. Developed physical and chemical heavy metal remediation technologies are demanding costs which are not feasible, time-consuming, and release additional waste to the environment. This chapter summarises the problems related to heavy metal pollution and various remediation technologies. A case study in South Africa mines were also used.