title: An innovative nano-sorbent for selective solid-phase extraction and spectrophotometric determination of p-amino benzoic acid in cosmetic products.
abstract: OBJECTIVE
  A novel nano-sorbent was developed for selective extraction and pre-concentration of p-amino benzoic acid (PABA) prior to determination by spectrophotometry.
  
  
  METHODS
  Selective extraction of PABA from aqueous solutions was performed using a solid-phase extraction column packed with 200 mg of nickel-zinc-aluminium layered double hydroxide (Ni-Zn-Al LDH) as a nano-sorbent. Extraction procedure is based on the adsorption of p-amino benzoate ions on the Ni-Zn-Al-nitrate LDH and/or their exchanging with LDH interlayer nitrate ions. After elution of extracted analyte by 2.5 mL of 2 mol L(-1) NaCl solution, its concentration was determined spectrophotometrically at λmax = 268 nm.
  
  
  RESULTS
  The spectrophotometry method gave a linear response for PABA within the range of 12.5-425.0 μg L(-1) with a correlation coefficient of 0.9994. In the optimum experimental conditions, the limit of detection and sorption capacity were 3.78 μg L(-1) and 21.25 mg g(-1) , respectively.
  
  
  CONCLUSIONS
  The presented method uses mild separation conditions and is a sensitive, reproducible, simple, low-cost and environment-friendly technique that could be used for the extraction and determination of PABA in various cosmetic samples.
authors.affiliation: Department of Chemistry, Faculty of Sciences, Azarbaijan Shadid Madani University, 35 Km Tabriz-Marageh Road, PO Box 53714-161, Tabriz, Iran.
authors.forename: H
authors.initials: H
authors.lastname: Abdolmohammad-Zadeh
authors.forename: S
authors.initials: S
authors.lastname: Falaghi
authors.forename: E
authors.initials: E
authors.lastname: Rahimpour
mesh_terms: D010129:4-Aminobenzoic Acid / Q000032:analysis*; D000536:Aluminum Hydroxide / Q000737:chemistry; D003358:Cosmetics / Q000737:chemistry*; D006878:Hydroxides / Q000737:chemistry; D049329:Nanostructures / Q000737:chemistry*; D009532:Nickel / Q000737:chemistry; D052616:Solid Phase Extraction / Q000379:methods*; D013056:Spectrophotometry, Ultraviolet; D017967:Zinc Compounds / Q000737:chemistry
chemical_list: D003358:Cosmetics; D006878:Hydroxides; D017967:Zinc Compounds; C037473:nickel hydroxide; D000536:Aluminum Hydroxide; D009532:Nickel; C052745:zinc hydroxide; D010129:4-Aminobenzoic Acid
keywords: chemical analysis; cosmetics; nickel-zinc-aluminium layered double hydroxide; p-amino benzoic acid; solid-phase extraction; spectroscopy