Paper Title
Determination of 27 Phytochemicals In Walnut Varieties With a Comprehensive, Validated LC-MS/MS Method

Abstract
Walnut (Juglans regia L.) is the oldest cultivated nut in the world and Turkey is one of the most important countries in the world in terms of walnut production1. The aim of this study was to determine phenolic compositions of eleven walnut genotypes from Mardin and two commercial cultivars from Sanliurfa provinces located in Southeast of Turkey. To qualify and quantify the phenolic compounds, a comprehensive and previously validated LC-MS/MS method was used2. Analytical method validation parameters; retention time (RT), coefficient of determination (R2), relative standard deviation (RSD), recovery, percent relative uncertainty at 95% confidence level (k=2) (U) were given in Table 1. Correlation coefficients were found to be higher than 0.99. The limit of detection (LOD) and the limit of quantitation (LOQ) of the reported analytical method were shown in Table 2. For the studied compounds, LOD ranged from 0.05–25.8 μg/L and LOQ ranged from 0.17–85.9 μg/L. Moreover, the recoveries of the phenolic compounds ranged from 96.9% to 106.2%..The majority of the phenolic compounds were phenolic acids, all of the samples were poor in terms of flavonoids. Quinic, malic, tr-aconitic, gallic, protocatechuic, tannic, caffeic and p-coumaric acids and naringenin were the detected compounds. Of all the samples MDE42 was the richest genotype in terms of phenolic compounds (2164.63, 41690.09, 177.32, 2160.31, 103.35, 494926.52, 25.77, 254.37, 16.60 respectively. Generally speaking, all of the samples contained significant amounts of tannic and malic acids.