Browsing by Author "Cooray, A. T."

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    Method validation for the detection of undeclared Furosemide drug contaminations in herbal weight loss supplements using LC-MS/MS
    (Faculty of Science, University of Kelaniya Sri Lanka, 2024) Ranasinghe, R. M. S. T. B.; Cooray, A. T.; Rashani, S. A. N.; De Silva, A.; Fernando, P. N.
    Numerous herbal weight loss supplements are widely consumed globally; however, there is a general concern regarding undeclared synthetic substances. Furosemide (4-chloro-2-(furan-2-ylmethylamino)- 5-sulfamoylbenzoic acid) is a potent diuretic substance, and it is prohibited for athletes due its ability to mask the presence of performance enhancing drugs in urine and its ability for rapid weight loss by excreted water as urine. This study aims to validate a new method for the detection of undeclared furosemide in weight loss supplements available in the local market using LC-MS/MS. In developing the method validation protocol, after testing the recovery and the matrix effect for suitability, two different herbal weight loss supplements were pulverised and mixed to make the blank matrix. Then 100.0 mg of the mixture was introduced to a centrifuge tube and 10.0 mL acetonitrile (LC/MS grade) was added to it, and sonicated for 10 minutes. The resultant solution was centrifuged for 10 minutes at 5000 rpm and the supernatant was double diluted and filtered using nylon filters (0.22μm). Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) extraction was used for coloured extractants. Seventeen (17) commercially available weight loss supplements were purchased from local retailers and analysed for the presence of furosemide using the developed method. In the developed method, a 1:1 ACN:Water mobile phase, biphenyl column operating at 40°C, 0.2 sec loop time was used. Under these conditions, the retention time of furosemide is 3.82 minutes. The developed method was validated according to the ICH (M10 2022) and Eurachem guidelines (second edition 2014). The linearity (r2 = 0.99) of the calibration plot, selectivity, LOD (0.14 nmol m-3) and LOQ (0.48 nmol m-3), trueness (±15%), precision (±5%), recovery (70.96%-81.06%) and matrix effects (103.0%-107.1%) were determined to ensure the method's validity for the intended purpose. None of the supplements contained detectable furosemide levels using the validated LC/MS/MS method. The absence of detectable furosemide in the analysed samples suggests that the tested supplements may not be adulterated with this specific diuretic or it is below the detection limit of this method.
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    Synthesis of black natural dye from locally available, sustainable and commercially viable ingredients
    (Faculty of Science, University of Kelaniya Sri Lanka, 2024) Patabendige, P. S. S.; Cooray, A. T.; Ariyananda, P.
    The textile industry, ranked as the second-largest polluter globally, significantly contributes to water pollution by using synthetic dyes and other chemicals in textile treatment processes. In response to the growing global interest in green chemistry and sustainability, leading multinational companies are urging textile industries to adopt more sustainable practices. As a solution to this issue, there is a shift towards replacing synthetic dyes with natural dyes, which offer greater sustainability, biodegradability, and environmental friendliness. Among various color shades, obtaining a natural black dye poses a greater challenge, making it a focal point of interest for industries seeking alternatives. In this research study, the objectives were to identify locally available, sustainable, and commercially viable sources capable of producing black shade, to check the affinity of the dye with the fabrics, and to compare the colour strength of natural black dye with synthetic black dye. The focus was on using the obtained natural black dye to dye synthetic fabrics such as Nylon. The combination of Terminalia chebula and Caesalpinia sappan, along with Ferrous sulphate (FeSO4) as the mordant was employed in the production of the natural black dye. Moreover, the exhaust dyeing method was employed at 98 ºC for 90 minutes, at pH value of 5.5 for maximum extraction and absorption of dye to the Nylon fabric. In the research study, Terminalia chebula and Caesalpinia sappan were found to produce a blueish-black colour which closely resembled the shade of synthetic black dye. Although natural dyes are typically recommended for use with natural fabrics, the produced natural black dye exhibited good performance on synthetic Nylon fabric which was tested using ISO standard methods. The natural black dye that was produced showed excellent colorfastness in terms of colour change and colour staining, while exhibiting moderate colorfastness in relation to wet and dry rubbing which was indicated that the black dye had satisfactory colour fastness properties on Nylon. To ensure sustainable measures, the exhaust dyeing technique was employed with minimal usage of resources, chemicals, and energy. Comparative analysis using Data colour spectroscopy confirmed that the natural black dye developed in this study closely resembled the synthetic black dye commonly used in industry. The attempt of industry to find natural black shade, which is a challenging colour to achieve, exhibited promising results and replacing synthetic black dye in industry with natural black is somewhat succeeded. To improve adhesion and shade of the dye, the following methods are recommended; such as, to treat the produced natural black dye with alkali reduction methods to improve adhesion to fabric surface, and to isolate the chebulic acid from Terminalia chebula and to isolate brazilin from Caesalpinia sappan.