Synthesis and Characterization of Fluorocarbon from Rice Husk and its Application as an Efficient Sorbent for Micro-Solid-Phase Extraction of N-Nitrosamines in Desalinated Water Samples

Fluorocarbon derived from rice husk was synthesized and utilized as an efficient sorbent for micro-solid-phase extraction to determine N-nitrosamines in desalinated water samples. Three different sorbents from pure rice husk (rice husk ash, sulfonated rice husk, and fluorocarbon) were synthesized. Various techniques were used to characterize the physicochemical properties of the sorbents. N-Nitrosamine mixtures (N-nitrosodimethylamine, N-nitrosodi-n-propylamine, and N-nitrosodiphenylamine) were used as target analytes for micro-solid-phase extraction. The factors influencing the performance of micro-solid-phase extraction, such as the selection of suitable sorbent, desorption solvent, desorption time, sample pH, and extraction time, were optimized. Under the optimized conditions, the newly improved micro-solid-phase extraction method provided a linear range between 1.0 and 50 µg/L with R² value ranges from 0.9916 to 0.9998. The limit of quantification ranges between 0.01 and 0.004 µg/L with satisfactory intraday and interday precision ranging from 3.9 to 5.1% and 4.7 to 7.5%, respectively. Recovery experiments evaluated the accuracy of the micro-solid-phase extraction; the recoveries were in the range of 85.6–102.4%. The micro-solid-phase extraction method was successfully utilized for the sensitive, accurate, and precise trace-level detection of N-nitrosamines in desalinated water samples with satisfactory results.