## 4 Conclusions  
A simple and efficient method was developed for the quantification of morphine, codeine, thebaine, papaverine and noscapine concentrations in poppy seed teas using \(\upmu\)SPEed(r) followed by GC-MS analysis. Of the nine \(\upmu\)SPEed(r) cartridges evaluated, PS/DVB-RP was the one most efficient for OAs and allowed, with optimized conditions, the elimination of possible matrix effects of the extract and 10-times concentrations, thus decreasing the MDLs and MQLs. Once the method was successfully validated, it was applied to study the rate of transfer of opiates from poppy seeds to teas. For this, the influence of three factors (temperature, time and quantity) was evaluated at two levels and it was determined that 4 g of seeds at 90 \({}^{\circ}\)C for 5 min were the conditions that produced the highest rate of transfer or less thermal degradation (75% morphine, 90% codeine, 96% thebaine, and 100% papaverine and noscapine). With these conditions, four teas made with different poppy seeds were quantified, and for all of them all the OAs were determined, one of which showed high morphine (1563 \(\upmu\)g/L) and codeine (254 \(\upmu\)g/L) contents, indicating that the seeds used contained 53 mg/kg morphine equivalents--twice the maximum limit legislated by the EU (20 mg/kg). Therefore, it is necessary to warn the population of the danger of not following the consumption recommendations, since it may be thought that the OA contents in the seeds are not very high.  
The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/chemosensors11020094/s1](https://www.mdpi.com/article/10.3390/chemosensors11020094/s1)]([https://www.mdpi.com/article/10.3390/chemosensors11020094/s1](https://www.mdpi.com/article/10.3390/chemosensors11020094/s1)), Table S1: Registration of the different poppy seeds used to make the tea infusions, with descriptions, species and origins; Table S2: Summary of the transfer studies performed with the three factors under study and the two levels for each.  
Conceptualization, I.S., J.S.C. and S.M.-Z.; methodology, G.C.-H. and R.P.; validation, G.C.-H., R.P. and S.M.-Z.; formal analysis, G.C.-H. and R.P.; investigation, I.S., J.S.C., R.P. and S.M.-Z.; resources, G.C.-H.; data curation, G.C.-H.; writing--original draft preparation, I.S., S.M.-Z. and G.C.-H.; writing--review and editing, I.S., J.S.C., S.M.-Z., R.P. and G.C.-H.; supervision, I.S., J.S.C., R.P. and S.M.-Z.; project administration, I.S. and J.S.C.; funding acquisition, J.S.C. and I.S. All authors have read and agreed to the published version of the manuscript.  
This research was funded by MCIU/AEI/FEDER, UE for project RTI2018-094558-B-I00. This work was also funded by FCT-Fundacao para a Ciencia e a Tecnologia through the CQM Base Fund--UIDB/00674/2020--and the Programmatic Fund--UIDP/00674/2020--and by ARDIIT-Agencia Regional para o Desenvolvimento da Investigacao Tecnologia e Inovacao, through the project M1420-01-0145-FEDER-00005--Centro de Quimica da Madeira--CQM+ (Madeira 14-20 Program). The authors also acknowledge financial support from the Fundacao para a Ciencia e Tecnologia and Madeira 14-2020 program to the Portuguese Mass Spectrometry Network through the PROEQUIPRAM program, M14-20 M1420-01-0145-FEDER-000008.  
Not applicable.