## 3 Results
### Validated Regression Models of Commercial Poppy Seed Oil Samples
According to [PERSON] [49], models falling within the range of \(2.0\leq\text{RPD}\leq 2.4\) are suitable for rough screening, those with \(2.5\leq\text{RPD}\leq 2.9\) are deemed acceptable for screening purposes, while models in the range  
\begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline
**Parameter (\%)** & **Range** & \(\boldsymbol{n}\) 1  & **Factor** & **SECV 1 ** & **R\({}_{\text{CV}}\) 1 ** & **Range** & \(\boldsymbol{n}\) 1 ** & **R\({}_{\text{Pre}}\) 1 ** & **R\({}_{\text{FE}}\) 1 ** & **R\({}_{\text{FE}}\) 1 ** & **R\({}_{\text{FE}}\) 1 ** & **R\({}_{\text{FE}}\) 1 ** & **R\({}_{\text{FE}}\) 1 ** & **R\({}_{\text{FE}}\) 1 ** & **R\({}_{\text{FE}}\) 1 ** & **R\({}_{\text{FE}}\) 1 ** & **R\({}_{\text{FE}}\) 1 ** & **R\({}_{\text{FE}}\) 1 ** & **R\({}_{\text{FE}}\) 1 ** & **R\({}_{\text{FE}}\) 1 ** & **R\({}_{\text{FE}}\) 1 ** & **R\({}_{\text{FE}}\) 1 ** & **R\({}_{\text{FE}}\) 1 ** & **R\({}_{\text{FE}}\) 1 [FOOTNOTE:]Footnote 1: Number of samples used in calibration models. 9 Standard error of cross-validation. 7 Correlation coefficient of cross-validation. 6 Correlation coefficient of cross-validation. 7 Number of samples used in calibration models. 9 Standard error of cross-validation. 7 Correlation coefficient of prediction for external validation. 8 Normalizedof \(3.0\leq\text{RPD}\leq 3.4\) are considered appropriate for quality control. The RPD values of \(3.5\leq\text{RPD}\leq 4.0\) indicate applicability for process control, while RPD values above 4.1 show that the model demonstrates versatility for all kinds of applications. On the other hand, RER, which is defined as the ratio between the range of reference data in the external validation set and the SEP, is another important factor in determining the accuracy of the model. In most cases, the RER value is larger than the RPD, with larger RPD or RER values indicating better performance, according to [PERSON] [50]. Consequently, models featuring RER values of \(4.0\leq\text{RER}\) can be effectively utilized for screening purposes, those with \(10.0\leq\text{RER}\) are well-suited for quality control applications, and models exhibiting RER values of \(15.0\leq\text{RER}\) prove effective for quantification purposes, as outlined by [PERSON], and others [51]. Major fatty acid models were provided with RPD values of 2.9 to 6.1, respectively, and RER values of 8.4 to 13.1 (Table 2). According to the RPD results, the palmitic and oleic acid results can be used for any type of application, while the stearic and linolenic are appropriate for process control applications. On the other hand, our RER results demonstrate that palmitic and linolic acid models can be used for quality control applications [49; 51]. As mentioned previously, to our knowledge, no study worked on applying FT-IR spectroscopy for commercial poppy seed oil authentication. On the other hand, our PLSR models showed similar or better performances than the previous studies in the literature that worked on the application of determining fatty acid contents in various oils using vibrational spectroscopy [44; 52; 53]. That being said, the main limitation of the present study, despite the promising results obtained, is the sample size of 39, which is probably not representative of the full diversity of poppy seed oil available on the market, especially in regions other than Turkiye. While we tried to include all available samples from two major cities in Turkiye and online stores, there is room to include more samples from other cities and smaller producers within Turkiye and from other countries. Increasing the sample size and adding oils from a wider variety of geographical locations would enhance the generalizability and robustness of the model. Vibrational spectroscopy has evolved over the years to become an indispensable tool in the laboratory. The IR spectrometers used to be bulky, expensive units that required periodic maintenance to achieve good accuracy.