title: Analysis of co-eluted isomers of high-molecular weight polycyclic aromatic hydrocarbons in high performance liquid chromatography fractions via solid-phase nanoextraction and time-resolved Shpol'skii spectroscopy.
abstract: We present an accurate method for the determination of isomers of high-molecular weight polycyclic aromatic hydrocarbons co-eluted in HPLC fractions. The feasibility of this approach is demonstrated with two isomers of molecular weight 302 with identical mass fragmentation patterns, namely dibenzo[a,i]pyrene and naphtho[2,3-a]pyrene. Qualitative and quantitative analysis is carried out via laser-excited time-resolved Shpol'skii spectroscopy at liquid helium temperature. Unambiguous identification of co-eluted isomers is based on their characteristic 4.2 K line-narrowed spectra in n-octane as well as their fluorescence lifetimes. Pre-concentration of HPLC fractions prior to spectroscopic analysis is performed with the aid of gold nanoparticles via an environmentally friendly procedure. In addition to the two co-eluted isomers, the analytical figures of merit of the entire procedure were evaluated with dibenzo[a,l]pyrene, dibenzo[a,h]pyrene and dibenzo[a,e]pyrene. The analytical recoveries from drinking water samples varied between 98.2±5.5 (dibenzo[a,l]pyrene) and 102.7±3.2% (dibenzo[a,i]pyrene). The limits of detection ranged from 51.1 ng L(-1) (naphtho[2,3-a]pyrene) to 154 ng L(-1) (dibenzo[a,e]pyrene). The excellent analytical figures of merit associated to its HPLC compatibility makes this approach an attractive alternative for the analysis of co-eluted isomers with identical mass spectra.
authors.affiliation: Department of Chemistry, 4000 Central Florida Blvd, Physical Sciences Room 255, University of Central Florida, Orlando, FL 32816-2366, USA.
authors.forename: Walter B
authors.initials: WB
authors.lastname: Wilson
authors.forename: Andres D
authors.initials: AD
authors.lastname: Campiglia
mesh_terms: D000042:Absorption; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D008401:Gas Chromatography-Mass Spectrometry; D006046:Gold / Q000737:chemistry; D007536:Isomerism; D016014:Linear Models; D053768:Metal Nanoparticles / Q000737:chemistry; D008970:Molecular Weight; D036103:Nanotechnology; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D052616:Solid Phase Extraction; D052617:Solid Phase Microextraction / Q000379:methods*; D013050:Spectrometry, Fluorescence / Q000379:methods*; D014867:Water; D014874:Water Pollutants, Chemical / Q000032:analysis
chemical_list: D011084:Polycyclic Aromatic Hydrocarbons; D014874:Water Pollutants, Chemical; D014867:Water; D006046:Gold