Isolation and identification of oxidation products of guaiacol from brines and heated meat matrix

In this study we investigated the formation of the oxidation products of guaiacol in brines and heated meat matrix: 6-nitrosoguaiacol, 4-nitroguaiacol and 6-nitroguaiacol. For this purpose we applied a newly developed HPLC-UV and LC–MS method. For the first time, 6-nitrosoguaiacol was determined in brine and meat (containing guaiacol and sodium nitrite), which had been heated to 80 °C and subsequently subjected to simulated digestion. Application of 500 mg/L ascorbic acid to the brines reduced guaiacol degradation at pH 3 and simultaneously inhibited the formation of 6-nitrosoguaiacol compared to brines containing only 100 mg/L of ASC. The oxidation products were isolated with a new extraction method from meat samples containing 400 mg/kg sodium nitrite at pH 3.6 following simulated digestion. When oxygen was added, 6-nitrosoguaiacol was determined even at legally allowed levels (150 mg/kg) of the curing agent. Finally, we developed a new LC–MS method for the separation and qualitative determination of the four main smoke methoxyphenols.