en public specific orginal article <div style="text-align: justify;"><span style="font-size:11pt"><span style="line-height:115%"><span style="unicode-bidi:embed"><span calibri="" style="font-family:"><b><span style="font-size:10.0pt"><span style="line-height:115%"><span new="" roman="" style="font-family:" times="">Background</span></span></span></b><span style="font-size:10.0pt"><span style="line-height:115%"><span new="" roman="" style="font-family:" times="">: Astaxanthin is widely and naturally distributed in marine animals including, crustaceans, such as shrimp, crabs, and fish, such as salmon and trout. <b>Methods</b>: A total of 20 trout samples were collected from local market and were analyzed for astaxanthin via HPLC-UV. Analyte extraction was done by water, methanol, dichloromethane, and acetonitrile 4.5:85:5:45.5, <i>v/v/v/v</i>. <b>Results</b>: Despite the optimal conditions, analytical property of the method containing lower limit of quantitation (2.00 ng g-1) and upper limit of quantitation (1000 ng g-1), linearity (r₂=0.992), and recovery (103%) were acceptable. The results showed the range of 105 &plusmn; 0.09 - 875 &plusmn; 0.020 ng g-1. <b>Conclusion</b>: The method was successfully used to quantify the target analytes in all trout samples.<a name="_Hlk72102916"></a></span></span></span></span></span></span></span></div> Astaxanthin, High performance liquid chromatography, Fish, Upper limit of quantification (ULOQ), lower limit of quantification (LLOQ) 508 511 http://jnfs.ssu.ac.ir/browse.php?a_code=A-10-331-2&slc_lang=en&sid=1 Hamed Rahnavard Researcher28203@gmail.com 0000000245213400 Yes School of Agricultural Sciences and Food Industries, Ardestan Branch of Islamic Azad University.