New Grafted Nanosilica-Based Sorbent for Needle Trap Extraction of Polycyclic Aromatic Hydrocarbons from Water Samples Followed by GC/MS

Abstract

In this work, the preparation of a new grafted nanosilica-based sorbent was extensively investigated. An inexpensive modifier, cis-9-octadecenoic acid (oleic acid) was selected to be grafted on the surface of the nanosilica particles as the support. The grafting process was accurately confirmed by Fourier transform infra-red spectrometry (FT-IR). Applicability of the prepared sorbent was thoroughly examined by needle trap extraction (NTE) method. The grafted sorbent was dispersed in the appropriate solvent and carefully packed inside a steel needle. Feasibility of the method was completely examined using polycyclic aromatic hydrocarbons (PAHs), as model compounds. For extraction of analytes from aqueous samples, the prepared needle trap device (NTD) was placed in the headspace of the sample and another needle was also inserted into the sample solution to purge the circulating headspace into the sample. For increasing the extraction efficiency, influencing parameters including extraction time and temperature, flow rate of analyte through the needle trap, the ionic strength, desorption temperature, and time were optimized. The limit of detection (LOD) and relative standard deviation (RSD) values of the method under optimized conditions were 2-5 ng L -1 and 1.1-4.8%, respectively. The RSD% for fluorene was somewhat higher and a value of 16.8% at 40 ng L -1 was achieved. Finally the developed method was applied to the analysis of tap water and Zayandeh-roud river samples and the relative recovery (RR %) values were found to be in the range of 77-109%, under the optimized conditions.

Nanoadsorbents: Classification, Preparation, and Applications (with Emphasis on Aqueous Media)

“…Thus, the use of nanosilica for extraction of organic pollutants is rather inconsiderable. To overcome this problem, nanosilica particles must be grafted with an organic modifier . The PZC of SiO 2 is about 2–3, as reported in the literature; therefore, silica nanoparticles are negatively charged at higher and nutrient pH, and consequently, their dispersions in various water and biological media would be stable.…”

Needle Trap Device as a New Sampling and Preconcentration Approach for Volatile Organic Compounds of Herbal Medicines and its Application to the Analysis of Volatile Components inViola tianschanica

“…It was reported that the heating temperature is a key parameter influencing the extraction efficiency in the NTD method (Bagheri et al , ). In this study, the peak numbers and areas were used as criterions to optimise extraction conditions.…”

“…These results indicate that the overall chromatographic performance in terms of peak intensity or peak capacity is significantly altered by increasing the temperatures, but the number of peaks extracted reaches a maximum at 70°C. It is worthy to note that high temperatures might increase desorption of analytes from the sorbents, resulting in the decrease of the amounts of compounds being retained by the NTD methods (De Crom et al, 2010;Bagheri et al, 2011b). A temperature of 70°C was thus chosen as the optimised extraction temperature in further experiments.…”

A Hexagonally Ordered Nanoporous Silica-Based Fiber Coating for SPME of Polycyclic Aromatic Hydrocarbons from Water Followed by GC–MS

“…Because of their high partition coefficients and low water solubilities, it is very important to develop a highly sensitive analytical method to detect them in natural and waste water [19].…”