Determination of t,t-muconic acid in urine samples using a molecular imprinted polymer combined with simultaneous ethyl chloroformate derivatization and pre-concentration by dispersive liquid-liquid microextraction

Anal Bioanal Chem. 2013 Jan;405(1):341-9. doi: 10.1007/s00216-012-6474-9. Epub 2012 Oct 19.

Abstract

The present communication describes the preparation and evaluation of a molecularly imprinted polymer (MIP) as a solid-phase extraction (SPE) sorbent and simultaneous ethyl chloroformate (ECF) derivatization and pre-concentration by dispersive liquid-liquid microextraction (DLLME) for the analysis of t,t-muconic acid (t,t-MA) in urine samples using gas chromatography-mass spectrometry. The imprinting polymer was prepared using methacrylic acid as a functional monomer, ethylene glycol dimethacrylate as a cross-linker, 2,2-azobisisobutyronitrile as the initiator and t,t-MA as a template molecule. The imprinted polymer was evaluated for its use as a SPE sorbent by comparing both imprinted and non-imprinted polymers in terms of the recovery of t,t-MA from urine samples. Molecular modelling studies were performed in order to estimate the binding energy and efficiency of the MIP complex formed between the monomer and the t,t-MA. Various factors that can affect the extraction efficiency of MIP, such as the loading, washing and eluting conditions, were optimized; other factors that can affect the derivatization and DLLME pre-concentration were also optimized. MIP in combination with ECF derivatization and DLLME pre-concentration for t,t-MA exhibits good linearity, ranging from 0.125 to 2 μg mL(-1) (R(2) = 0.9971), with limit of detection of 0.037 μg mL(-1) and limit of quantification of 0.109 μg mL(-1). Intra- and inter-day precision was found to be <6%. The proposed method has been proven to be effective and sensitive for the selective pre-concentration and determination of t,t-MA in urine samples of cigarette smokers.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Calibration
  • Dose-Response Relationship, Drug
  • Formic Acid Esters / chemistry*
  • Gas Chromatography-Mass Spectrometry / methods
  • Humans
  • Liquid Phase Microextraction / methods*
  • Models, Molecular
  • Molecular Imprinting / methods*
  • Polymers / chemistry
  • Protein Binding
  • Reproducibility of Results
  • Smoking / urine
  • Solvents / chemistry
  • Sorbic Acid / analogs & derivatives
  • Sorbic Acid / chemistry
  • Tobacco Products
  • Urinalysis / methods*

Substances

  • Formic Acid Esters
  • Polymers
  • Solvents
  • ethyl chloroformate
  • muconic acid
  • Sorbic Acid