https://vital.seals.ac.za/vital/access/manager/Index ${session.getAttribute("locale")} 5 A study of electrospun nanofibers and diatomaceous earth materials for the extraction of alkaloids, flavonoids and aromatic amines in various matrices https://vital.seals.ac.za/vital/access/manager/Repository/vital:4288 Wed 12 May 2021 23:05:00 SAST ]]> Electrospun nanofibers as solid phase extraction sorbents and support for alkylphenols colorimetric probes https://vital.seals.ac.za/vital/access/manager/Repository/vital:4486 Wed 12 May 2021 18:44:44 SAST ]]> Electrospun sorbents for solid phase extraction (SPE) and colorimetric detection of pesticides https://vital.seals.ac.za/vital/access/manager/Repository/vital:4501 0. 96), demonstrating the fiber affinity to retain both polar and non-polar compounds opening a possibility to be used as sorbent for sample preparation of different classes of pesticides in water. For the second part of the study simple strategies for colorimetric sensing based on silver nanoparticles and polivinylpyrrolidone capped nanoparticles were developed, respectively for atrazine and chlorpyrifos detection. The limits of detection of the methods were 3.32 and 0.88 mg/L for atrazine and chlorpyrifos respectively. The applicability of the probe in real samples was demonstrated by the recoveries studies of tap water varying from 94 to 104 percent. The versatility of the probe was demonstrated by affording a simple, rapid and selective detection of atrazine and chlorpyrifos in the presence of other pesticides by direct analysis without employing any sample handling steps. Attempt to incorporate the probes in a solid support was achieved by using nylon 6 as solid support polymer proving to be fast and useful for on-site detection.]]> Wed 12 May 2021 17:40:49 SAST ]]> Solid-phase extraction based sample preparation for the determination of drug and organic pollutant residue https://vital.seals.ac.za/vital/access/manager/Repository/vital:4406 0.9990) was attained for most analytes. The limits of detection and quantification ranged from 0.03 - 0.84 μg/ml and 0.81 - 1.89 μg/ml respectively for analytes in biological samples. LODs and LOQs for analytes in food and environmental samples ranged from 0.02 to 0.39 and 0.25 to 1.30 ng/g respectively.]]> Wed 12 May 2021 17:31:55 SAST ]]> The development of platinum and palladium-selective polymeric materials https://vital.seals.ac.za/vital/access/manager/Repository/vital:4287 0.99. In the column experiment the highest loading capacity of Pt and Pd were 7.4 mg/g and 4.3 mg/g respectively on the nanofiber sorbent material based on ethylenediamine (EDA). The polystyrene and silica-based resins with triethylenetetramine (TETA) functionality (M-TETA and S-TETA) showed selectivity for platinum and palladium, respectively. Metal chlorido complexes loaded on the sorbent materials were recovered by using 3% m/v thiourea solution as teh eluting agent with quantitative desorption efficiency under the selected experimental conditions. The separation of platinum from palladium was partially achieved by selective stripping of PtCl₆²⁻ with 0.5 M of NaClO₄ in 1.0 M HCI with PdCl₄²⁻ was eluted with 0.5 M thiourea in 1.0 M HCI. The selectivity of the M-TETA and S-TETA sorbent materials was proved by column separation of platinum(IV) and palladium(II), respectively, from synthetic solutions containing iridium(IV) and rhodium(III). The loading capacity for platinum on M-TETA was 0.09 mg/g while it was 0.27 mg/g for palladium on S-TETA.]]> Thu 13 May 2021 07:36:09 SAST ]]>