In a different context, considering the continuous search for new treatment strategies for human immunodeficiency virus (HIV) infection, an HPLC-MS/MS method was developed for the simultaneous quantification of the antiretrovirals tenofovir and efavirenz. The target samples were mice tissue and fluid samples recovered from a pharmacokinetics study with nanoparticles [2]. Finally, BIBP 3226 is a selective neuropeptide Y Y1 receptor antagonist that has proved a positive impact in in vitro bone turnover, thus providing good perspectives towards its application as a pharmacological tool for bone regeneration. Keeping in mind the need to elucidate receptor-anagonist internalization mechanisms, the challenge was to develop a methodology based on HPLC-MS/MS that permitted us to determine the low quantities of antagonist expected to be internalized by cells [3]. **Funding:** This work received financial support from PT national funds (FCT/MCTES, Fundacao para a Ciencia e a Tecnologia and Ministerio da Ciencia, Tecnologia e Ensino Superior) through the project UIDB/50006/2020. L. Barreiros acknowledges funding from FCT through program DL 57/2016--Norma transitoria. S.R. Fernandes and S. Machado thank FCT and ESF (European Social Fund) through NORTE2020 (Programa Operacional Regional Norte) for their PhD grants (SFRH/BD/130948/2017 and SFRH/BD/122730/2016). ## References  
* Barreiros et al. (2019) Barreiros, L.; Amoreira, J.L. ; Machado, S.; Fernandes, S.R. ; Silva, E.M.P. ; Sa, P.; Kiteaibl, S.; Segundo, M.A. Determination of tranexamic acid in human plasma by UHPLC coupled with tandem mass spectrometry targeting sub-microgram per milliliter levels. _Microchem. J._**2019**, _144_, 144-150. * Barreiros et al. (2017) Barreiros, L.; Cunha-Reis, C.; Silva, E.M.P. ; Carvalho, J.R.B. ; das Neves, J.; Sarmento, B.; Segundo, M.A. Development and validation of a liquid chromatography-MS/MS method for simultaneous quantification of tenofovir and afavienz in biological tissues and fluids. _J. Pharm. Biomed. Anal._**2017**, _136_, 120-125. * Barreiros et al. (2020) Barreiros, L.; Silva, E.M.P. ; Alencastre, I.S. ; Lamghari, M.; Segundo, M.A. Determination of neuropeptide Y Y1 receptor antagonist BIBP 3226 and evaluation of receptor expression based on liquid chromatography coupled with tandem mass spectrometry. _Anal. Bioanal. Chem._**2020**, _412_, 6625-6632. * S. (2020)_Prediction of Acute Aquatic Ecotoxicity of Emerging Contaminants Using Biomimetic Chromatographic Measurements_**C. Stergiopoulos 1,* F. Tsopelas 1, K. Valko 2 and M. Ochsenkuhn-Petropoulou 1**
* Laboratory of Inorganic and Analytical Chemistry, School of Chemical Engineering, National Technical University of Athens, 10431 Athens, Greece
* Bio-Mimetic Chromatography Ltd., Herts, Stevenage SG1 1 AP, UK
* Correspondence: chrisxp3@hotmail.com  
The presence of emerging contaminants in aquatic environments can have adverse effects on ecosystems and long-term consequences on human health [1]. Therefore, hazard assessment of compounds seems inevitable in order to evaluate their ecological risk, although no specific regulations seem to exist until nowadays [2]. In this work, the potential of biomimetic chromatography to predict ecotoxicological endpoints of organic compounds of emerging concern was investigated. For this purpose, retention factors of 36 structurally diverse drugs and 39 structurally diverse pesticides were measured on immobilized artificial membrane (IAM), immobilized human serum albumin (HSA) and immobilized alpha-1-acid-glycoprotein (AGP) stationary phases [3]. As ecotoxicological endpoints, half-maximal lethal concentration (LC50) values of fish (rainbow trout, fathead minnow, bluegill sunfish, and sheepshead minnow species) and half-maximal effective concentration (EC50--immobilization) values of water flea (daphnia magna spp.) were considered [4]. Data were compiled from the US Environmental Protection Agency (EPA). For reasons of comparison, corresponding models were derived using calculated physicochemical properties.