ECL Method for the Determination of Skatole in Pig Plasma

Abstract

Skatole is one of the compounds responsible for the unpleasant odor found in tainted boar meat. Its quantification in blood plasma could allow for the identification of tainted carcasses for selective breeding or research purposes with measures in live animals. Toward this goal, we demonstrate that skatole may be quantified after extraction in blood plasma by electrochemiluminescence (ECL) using boron-doped diamond electrodes. First, a method for extracting skatole from plasma into acetonitrile for further analysis has been developed. Additionally, for the first time, native skatole has been detected in pig plasma samples using ECL for the determination of boar taint in pigs. A double extraction was achieved using an intermediate step with commercial rapeseed oil at a ratio of 1:4:10 (plasma/rapeseed oil/acetonitrile). Using standard solutions of deionized water spiked with skatole (50–1000 nM), a calibration curve demonstrated good linearity with a coefficient of determination (R²) of 0.9948, a limit of detection of 37 nM (4.84 ng/mL), and a limit of quantification of 227 nM (29.69 ng/mL). Then, 24 pig plasma samples were analyzed, and the resulting skatole concentrations were compared with those contained in the fat of the same animals and determined using the “gold standard” technique, HPLC. The results reported here indicate a Pearson correlation coefficient (R²) of 0.96. All of the pig samples that displayed an elevated skatole concentration above the consumer acceptance threshold can be identified from plasma analysis alone, thus demonstrating that plasma detection with ECL can be utilized for the determination of boar taint.