Abstract:A high performance liquid chromatography method was established for the determination of betaine content in food. The extraction process of betaine was optimized through single factor and orthogonal experiments. The optimal extraction process was determined as follows：100% methanol solution as the extraction solvent，a solid-to-liquid ratio of 1∶25 （g/mL），an extraction temperature of 45 ℃，an extraction time of 10 min，and an extraction method of thermostatic water bath with oscillation. The chromatographic conditions were optimized as follows：a normal-phase silica gel column （5 μm，4.6 mm×150 mm），isocratic elution with acetonitrile∶water=80∶20（volume ratio），a flow rate of 1 mL/min，a column temperature of 30 ℃，and a detection wavelength of 196 nm. Under these conditions，a good linear relationship was observed when the concentration of betaine was between 0.01 and 1.00 mg/mL. The detection limit of betaine was 1.0 mg/100 g and the quantification limit was 3.0 mg/100 g. The relative standard deviations of betaine determination in dried goji berry，quinoa，and spinach samples were all less than 3.8%，indicating that the method had good precision and was suitable for quantitative analysis. The recovery rates of betaine in dried goji berry，quinoa，and spinach samples were 95.32%-104.65%，95.19%-104.37%，and 95.42%-104.47%，respectively. Under optimized extraction and determination processes，betaine in the samples was effectively separated and efficiently recovered. The method established in this study was suitable for the determination of betaine content in food.