Paper Information

Title: 

FACTORS INFLUENCING SAMPLE PREPARATION OF MANDELIC ACID AS AN OCCUPATIONAL BIOMARKER OF STYRENE

Type: SPEECH
Author(s): ABDOLLAHI M.,SHAHTAHERI S.J.A.D.,GOLBABAEI F.,RAHIMI FOROUSHANI A.
 
 
 
Name of Seminar: IRANIAN CONGRESS OF TOXICOLOGY
Type of Seminar:  CONGRESS
Sponsor:  SOCIETY OF TOXICOLOGY
Date:  2004Volume 8
 
 
Abstract: 

Ethyl benzene and styrene are important constituents of widely used solvents in industry and laboratories, causing widespread environmental and industrial pollutions. For the evaluation of occupational exposure to such pollutants, biological monitoring is an essential process. Preparation of biological samples is one of the most time- consuming and error-prone aspects prior to chromatographic techniques. The main objective of this study was to assess how different factors can affect on sample preparation stages when the trace level determinations are of interest. Methods: The use of solid-phase extraction (SPE) has grown and is a fertile technique of sample preparation as it provides better results than those produced by liquid-liquid extraction (LLE). In this study, SPE using bonded silica has been optimized with regard to sample pH, sample concentration, sample flow rate, elution solvent, washing solvent, sample volume, elution volume, sorbent type, and sorbent mass. A high performance liquid chromatography, using reverse-phase column (250 × 4.6 ID mm, 5µm) was used and a careful control of temperature (25oC) was performed. The isocratic run was done at a constant flow rate of 0.85ml/min; the mobile phase consisted of water, methanol, and acetic acid (69:30:1 v/v), and a UV detector was used and set at 225nm. Under these conditions, the compound of interest was eluted and detected at 7.6min Results: Through experimental evaluation, a strong anion exchange silica cartridge (SAX) has been found successful in simplifying sample preparation. The present approach proved that, mandelic acid could be retained on SAX based on specific interaction. Further study was employed 10% acetic acid to extract the analyte from spiked urine and gave a clean sample for HPLC-UV system. At the developed conditions the extraction recovery exceeded 98%. The factors was evaluated statically and also validated with three different pools of spiked samples and showed a good reproducibility over six consecutive days as well as six within-day experiments. Conclusions: The procedure developed during this study, has shown that solid phase extraction using silica-bonded is more advantageous than liquid-liquid extraction. Depending on chemical and physical properties of the analyte, manipulating of the factors involving sorbent types, sample pH, type and volume of eluent can play a main role in optimizing the method, providing reliable, easy to use, and cost effective procedure to overcome difficulties associated with other sample preparation techniques. Applicability of the method for treatment of different classes of pollutants such as pesticides and different hydrocarbons can make the technique to be popular when a selective and sensitive trace residue analysis is required. SPE is a fertile area for sample preparation methods and based on the needs and facilities can be more developed in the near future.

 
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