Optimization of extraction procedure for formaldehyde assay in smoked meat products

To establish a formaldehyde detection method, including a method of extraction, in traditional smoked meat products, steam distillation was chosen as the preparation method. The effects of distillation time, 10% phosphoric acid solutions dosage, soaking time and water coolant flow rate on the extraction amount of formaldehyde were investigated. An orthogonal design L9 (34) was applied to optimize the extraction conditions. The following optimum extraction conditions were determined: distillation time of 50 min, 10% phosphoric acid solution dosage of 3 mL, soaking time of 2 h and water coolant flow rate of 2.2 × 10−5 m3/s. The recoveries of standard additions of formaldehyde (10, 20, and 30 mg/kg) were found to be 85.79%, 91.64% and 83.45%, respectively. The repeatability relative standard deviation (RSD) was 2.669%, and the reproducibility RSD was 6.536%. The detection limit was 0.4602 mg/kg with the proposed method in smoked meat products. The smoked meat products contained high formaldehyde concentrations (up to 125 mg/kg wet weight) when the proposed method was used.