Abstract
BHT is an antioxidant utilized as additive in some foods and in packaging plastics, and its presence in bottled mineral water is possible due to its migration from bottle walls to the contents. A factorial experimental design was utilized to obtain the optimum values for the main operational parameters in the analysis of butylated hydroxytoluene (BHT) in bottled water using headspace and direct solid-phase microextraction (SPME) in the pre-concentration step. The parameters optimized were sample pH, temperature and ionic strength. The separation, detection and quantitation of the extracts were performed by gas chromatography coupled to mass spectrometry. Preliminary experiments were made to select the best fiber for the extraction procedure. Polydimethylsiloxane (PDMS) fibers were selected, and the optimized methodology was successfully applied to the extraction and quantitation of BHT in real samples of mineral and mineralized bottled water.
Highlights
Univariate studies evaluating the capabilities of different fibers, the effects of temperature, pH and salinity were evaluated by a two-level factorial design to obtain the optimal conditions for direct immersion (D-solid-phase microextraction (SPME)) and headspace (HS-SPME) modes
Solid Phase Microextraction, introduced by Arthur and Pawliszyn in 1990 1 as a modern alternative to traditional sample preparation technology, is able to address many of the requirements put forward for analytical research.[2]
A preliminary report on the specific application of direct immersion solid-phase microextraction (SPME) for BHT determination in plastic-bottled water was already done,[9] suggesting that this technique is a good alternative for fast and accurate analyse; further optimization optimization was found to be necessary before proposing it as a routine procedure
Summary
Univariate studies evaluating the capabilities of different fibers, the effects of temperature, pH and salinity were evaluated by a two-level factorial design to obtain the optimal conditions for direct immersion (D-SPME) and headspace (HS-SPME) modes. A multivariate simultaneous approach was initially adopted to study the effects of variations of the chosen parameters on extraction efficiency, using a set of experiments arranged through a 23 factorial design.[11] The values for the upper (+) and lower (-) levels of each variable were: pH 2.5 and 6.5; temperature = 25 oC and 75 oC; and ionic strength = zero and 30 g NaCl/100 mL solution.
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