title: Dissolvable layered double hydroxide as an efficient nanosorbent for centrifugeless air-agitated dispersive solid-phase extraction of potentially toxic metal ions from bio-fluid samples.
abstract: In the present work, a novel nanosorbent namely layered double hydroxides with 4-amino-5-hydroxyl-2,7-naphthalendisulfonic acid monosodium salt interlayer anion (Mg-Al-AHNDA-LDH) was synthesized and applied as a dissolvable nanosorbent in a centrifugeless ultrasound-enhanced air-agitated dispersive solid-phase extraction (USE-AA-D-SPE) method. This method was used for the separation and preconcentration of some metal ions including Cd2+, Cr6+, Pb2+, Co2+, and Ni2+prior to their determination using the micro-sampling flame atomic absorption spectrometry (MS-FAAS) technique. The most interesting aspect of this nanosorbent is its immediate dissolvability at pH values lower than 4. This capability drastically eliminates the elution step, leading to a great improvement in the extraction efficiency and a decrease in the extraction time. Also in this method, the use of a syringe nanofilter eliminates the need for the centrifugation step, which is time-consuming and essentially causes the analysis to be off-line. Several effective parameters governing the extraction efficiency including the sample solution pH, amount of nanosorbent, eluent condition, number of air-agitation cycles, and sonication time were investigated and optimized. Under the optimized conditions, the good linear dynamic ranges of 2-70, 6-360, 7-725, 7-370, and 8-450 ng mL-1for the Cd2+, Cr6+, Pb2+, Co2+and Ni2+ions, respectively, with the correlation of determinations (R2s) higher than 0.997 were obtained. The limits of detection (LODs) were found to be 0.6, 1.7, 2.0, 2.1, and 2.4 for the Cd2+, Cr6+, Pb2+, Co2+, and Ni2+ions, respectively. The intra-day and inter-day precisions (percent relative standard deviations (%RSDs) (n = 5)) were below 7.8%. The proposed method was also successfully applied for the extraction and determination of the target ions in different biological fluid and tap water samples.
authors.affiliation: Department of Chemistry, Semnan University, Semnan 35195-363, Iran. Electronic address: mrajabi@semnan.ac.ir.
authors.forename: Maryam
authors.initials: M
authors.lastname: Rajabi
authors.affiliation: Department of Chemistry, Semnan University, Semnan 35195-363, Iran.
authors.forename: Somayeh
authors.initials: S
authors.lastname: Arghavani-Beydokhti
authors.affiliation: Department of Chemistry, Semnan University, Semnan 35195-363, Iran.
authors.forename: Behruz
authors.initials: B
authors.lastname: Barfi
authors.affiliation: Department of Chemistry, Semnan University, Semnan 35195-363, Iran.
authors.forename: Alireza
authors.initials: A
authors.lastname: Asghari
mesh_terms: D060766:Drinking Water / Q000737:chemistry; D006197:Hair / Q000737:chemistry; D006801:Humans; D006878:Hydroxides; D057230:Limit of Detection; D008670:Metals / Q000302:isolation & purification*; D009262:Nails / Q000737:chemistry; D010949:Plasma / Q000737:chemistry; D012463:Saliva / Q000737:chemistry; D052616:Solid Phase Extraction; D013054:Spectrophotometry, Atomic; D014556:Urine / Q000737:chemistry; D014874:Water Pollutants, Chemical
chemical_list: D060766:Drinking Water; D006878:Hydroxides; D008670:Metals; D014874:Water Pollutants, Chemical
keywords: Air-agitated; Bio-fluids; Centrifugeless; Dispersive solid-phase extraction; Layered double hydroxide; Micro-sampling