{"id":{"repo_id":"cape-town","oai_identifier":"oai:open.uct.ac.za:11427/37046"},"canonical_url":"https://search.dev.ndltd.org/etd/cape-town/oai:open.uct.ac.za:11427/37046","repository":{"repo_id":"cape-town","name":"University of Cape Town","base_url":"https://open.uct.ac.za/oai/request"},"display":{"title":"Development of a simple HPLC-UV method for determination of GFR by serum iohexol clearance","abstract":"The glomerular filtration rate (GFR) is considered the best indicator of kidney function. Iohexol, a contrast agent, is currently considered to be a reference marker since it meets all the requirements of an ideal GFR marker. The aim of this study was to develop and validate a method for iohexol measurement using high performance liquid chromatography with ultraviolet detection (HPLCUV). The method developed includes a mobile phase with water and acetonitrile with a gradient of 5%-30% organic, a C18 analytical column (100 × 4.6 mm, 2.7 µm particle size) at a temperature of 40 °C and a flow rate of 0.5 ml/min. Serum samples were deproteinized by addition of perchloric acid (5%). The assay met the sensitivity cut-off with a mean signal-to-noise ratio of 17.2 at a level of 10 µg/mL iohexol. Mean recovery was 103.7% (CV=4.4%). The dilution experiment allowed for 5-times dilution up to iohexol levels of 500 µg/mL with an accuracy of 103.1% (CV=1.3%) For selectivity, no interfering endogenous compounds at the retention time of iohexol were observed. The matrix effect experiment showed a clinically acceptable variation at all concentration levels with a CV of the slopes of 2.7%. Stability of the stock solution was proven for at least 9 months at -80°C. Sample post-extraction stability was adequate at 84 hours. Interference testing yielded between -7% and -12% difference at 2% haemolysis and -9% to -13% difference at 10% lipaemia. With regards to these findings, this method is simple, specific, linear, precise and robust, which allows its application for the measurement of GFR in serum.","abstract_html":"The glomerular filtration rate (GFR) is considered the best indicator of kidney function. Iohexol, a contrast agent, is currently considered to be a reference marker since it meets all the requirements of an ideal GFR marker. The aim of this study was to develop and validate a method for iohexol measurement using high performance liquid chromatography with ultraviolet detection (HPLCUV). The method developed includes a mobile phase with water and acetonitrile with a gradient of 5%-30% organic, a C18 analytical column (100 × 4.6 mm, 2.7 µm particle size) at a temperature of 40 °C and a flow rate of 0.5 ml/min. Serum samples were deproteinized by addition of perchloric acid (5%). The assay met the sensitivity cut-off with a mean signal-to-noise ratio of 17.2 at a level of 10 µg/mL iohexol. Mean recovery was 103.7% (CV=4.4%). The dilution experiment allowed for 5-times dilution up to iohexol levels of 500 µg/mL with an accuracy of 103.1% (CV=1.3%) For selectivity, no interfering endogenous compounds at the retention time of iohexol were observed. The matrix effect experiment showed a clinically acceptable variation at all concentration levels with a CV of the slopes of 2.7%. Stability of the stock solution was proven for at least 9 months at -80°C. Sample post-extraction stability was adequate at 84 hours. Interference testing yielded between -7% and -12% difference at 2% haemolysis and -9% to -13% difference at 10% lipaemia. With regards to these findings, this method is simple, specific, linear, precise and robust, which allows its application for the measurement of GFR in serum.","abstract_has_math":false,"creators":["van Der Westhuizen, Diederick J"],"institution":"Department of Clinical Laboratory Sciences","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Pillay, Joanne","van der Watt, George"],"committee_chairs":[],"committee_members":[],"year":2022,"date_issued":"2022","date_published":"2022","updated_at":"2026-07-22T22:23:24Z","subjects":["Medicine"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/11427/37046","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Pillay, Joanne","van der Watt, George"]},{"key":"dc:creator","label":"Author","values":["van Der Westhuizen, Diederick J"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2023-02-23T12:16:49Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2023-02-23T12:16:49Z"]},{"key":"dc:date.issued","label":"Date","values":["2022"]},{"key":"dc:publisher.department","label":"Dc Publisher Department","values":["Department of Clinical Laboratory Sciences"]},{"key":"dc:type","label":"Dc Type","values":["Master Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["Masters","MMed"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Medicine"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/11427/37046"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["The glomerular filtration rate (GFR) is considered the best indicator of kidney function. Iohexol, a contrast agent, is currently considered to be a reference marker since it meets all the requirements of an ideal GFR marker. The aim of this study was to develop and validate a method for iohexol measurement using high performance liquid chromatography with ultraviolet detection (HPLCUV). The method developed includes a mobile phase with water and acetonitrile with a gradient of 5%-30% organic, a C18 analytical column (100 × 4.6 mm, 2.7 µm particle size) at a temperature of 40 °C and a flow rate of 0.5 ml/min. Serum samples were deproteinized by addition of perchloric acid (5%). The assay met the sensitivity cut-off with a mean signal-to-noise ratio of 17.2 at a level of 10 µg/mL iohexol. Mean recovery was 103.7% (CV=4.4%). The dilution experiment allowed for 5-times dilution up to iohexol levels of 500 µg/mL with an accuracy of 103.1% (CV=1.3%) For selectivity, no interfering endogenous compounds at the retention time of iohexol were observed. The matrix effect experiment showed a clinically acceptable variation at all concentration levels with a CV of the slopes of 2.7%. Stability of the stock solution was proven for at least 9 months at -80°C. Sample post-extraction stability was adequate at 84 hours. Interference testing yielded between -7% and -12% difference at 2% haemolysis and -9% to -13% difference at 10% lipaemia. With regards to these findings, this method is simple, specific, linear, precise and robust, which allows its application for the measurement of GFR in serum."]},{"key":"dc:title","label":"Title","values":["Development of a simple HPLC-UV method for determination of GFR by serum iohexol clearance"]}]}],"canonical_facts":{"dc:contributor.advisor":["Pillay, Joanne","van der Watt, George"],"dc:creator":["van Der Westhuizen, Diederick J"],"dc:date.accessioned":["2023-02-23T12:16:49Z"],"dc:date.available":["2023-02-23T12:16:49Z"],"dc:date.issued":["2022"],"dc:description.abstract":["The glomerular filtration rate (GFR) is considered the best indicator of kidney function. Iohexol, a contrast agent, is currently considered to be a reference marker since it meets all the requirements of an ideal GFR marker. The aim of this study was to develop and validate a method for iohexol measurement using high performance liquid chromatography with ultraviolet detection (HPLCUV). The method developed includes a mobile phase with water and acetonitrile with a gradient of 5%-30% organic, a C18 analytical column (100 × 4.6 mm, 2.7 µm particle size) at a temperature of 40 °C and a flow rate of 0.5 ml/min. Serum samples were deproteinized by addition of perchloric acid (5%). The assay met the sensitivity cut-off with a mean signal-to-noise ratio of 17.2 at a level of 10 µg/mL iohexol. Mean recovery was 103.7% (CV=4.4%). The dilution experiment allowed for 5-times dilution up to iohexol levels of 500 µg/mL with an accuracy of 103.1% (CV=1.3%) For selectivity, no interfering endogenous compounds at the retention time of iohexol were observed. The matrix effect experiment showed a clinically acceptable variation at all concentration levels with a CV of the slopes of 2.7%. Stability of the stock solution was proven for at least 9 months at -80°C. Sample post-extraction stability was adequate at 84 hours. Interference testing yielded between -7% and -12% difference at 2% haemolysis and -9% to -13% difference at 10% lipaemia. With regards to these findings, this method is simple, specific, linear, precise and robust, which allows its application for the measurement of GFR in serum."],"dc:identifier.uri":["http://hdl.handle.net/11427/37046"],"dc:publisher.department":["Department of Clinical Laboratory Sciences"],"dc:subject":["Medicine"],"dc:title":["Development of a simple HPLC-UV method for determination of GFR by serum iohexol clearance"],"dc:type":["Master Thesis"],"dc:type.qualificationlevel":["Masters","MMed"]},"updated_at":"2026-07-22T22:23:24Z"}