Only slices are measured of very long segments of solute molecules that are injected into columns in chromatographic systems. Since the concentration of solute molecules changes during elution as a function of time, the observed signal should be reconstructed for a comparison of experimental results with theory. The influence of response time on the observed signal in high-performance liquid chromatography experiments was investigated in detail using a C-18 column for the measurement of caffeine in pure methanol as eluent. The response function influenced the observed signal by converting the square signal of pulse flow into a chromatographic peak. At faster linear flow rates (LFRs), the response function influenced the observed shape of the chromatographic peak, whereas diffusion dominated at slow LFRs. By convolution of the square signal with the response function, it was possible to predict the shape of the observed signal and chromatographic parameters and to provide an alternative explanation to the van Deemter equation. By using the shape of a known response function and modelling the new theory to data, it was proposed that the injected solute molecules were eluted over long distances through the chromatographic column, distances that are much longer than the physical length of the system.
Plate theory and adsorption theory are the main tools available for understanding chromatographic experiments. Both theories predict a Gaussian distribution of solute molecules within the tubular system. However, Gaussian concentration distributions are observed predominantly at slow linear flow rates, while asymmetric concentration distributions are observed at the linear flow rates most used in chromatography. Allegedly, this asymmetry originates from an inhomogeneous distribution of grain sizes in the column and column overload. However, it is an experimental fact that the distribution of chemicals within an injected volume of solute changes as a function of time, while the response is measured simultaneously. Accordingly, the obtained signal cannot be compared to the theory before some type of time‐based deconvolution of the data has been performed. Adjustments to high‐performance liquid chromatography data were thus proposed through empirical equations that describe the relevant time values, peak height, peak area, and parameters of the van Deemter equation. It was proposed that the transfer of solute from the front to the rear part of the pulse during laminar open‐ended flow occurs at rate that depends on the linear flow rate, and to a lesser extent, on properties of the response function.
Aims: To employ valorized waste materials from Tilapia ruweti scales for removal of heavy metals from areas with major boating activities and high numbers of jetties at the Okavango delta, Botswana. Study Design: Biowaste materials were Identified, valorized and then optimized for adsorption and removal of boating and jetty pollutants from profiled Okavango Delta surface water samples. Place and Duration of Study: Okavango Delta, Maun and Botswana International University of Science and Technology, Palapye, Botswana between March 2017 and September 2018. Methodology: Tilapia ruweti scales were collected from Sehithwa, Maun while water samples were collected from areas with jetties and major boating activities at Shakawe, Mboma Island and Xakanaxa. The concentration of Zn, Cu, Ni, Co, Pb and Cd at all the sampling sites were accurately determined using micro-plasma atomic emission spectroscopy (MPAES). The fish scales were pulverized and valorized by subjecting them to 12.7% vinegar. Minitab 14 software was used as a modeling tool to provide multivariate optimized parameters that affect sorption studies that included initial ion concentration, sorbent dose, contact time and solution pH. The valorized waste materials were then utilized for removal of the selected heavy metals. Results: The optimized adsorption parameters that included contact time, solution pH, sorbent dose and initial ion concentration were ≤ 88.63 min, ≤ 8.75, ≤ 84.29 mg and ≤ 28.44 mg/L respectively. The valorized Tilapia ruweti waste displayed high removal efficiencies toward removing the selected ions from the Okavango Delta surface water samples up to 94.21% with %RSD < 2 for n = 3 (triplicate). Conclusion: The valorized Tilapia ruweti scales were recommended as a cheap, simple and an effective method for remediation of boating pollution at the Okavango delta and other recreational areas.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.