One-way and two-way pulsed electromembrane extraction for trace analysis of amino acids in foods and biological samples

► Pulsed electromembrane extraction (PEME) was used for extraction of some amino acids. ► A mixture of NPOE and DEHP was used as the organic liquid membrane. ► The method offers good linearity with correlation coefficient higher than 0.9979. ► The method was applied to determine amino acids in foods and biological samples. ► Two-way PEME was employed for highly selective extraction of tryptophan.