abstract
Although saliva is a convenient human fluid for biomonitoring, current analytical set-ups for its analysis exhibit technical, sensitivity and instrumental compatibility constraints. To overcome these drawbacks, while following the Green Analytical Chemistry trends, this study is the first to propose the use of aqueous biphasic systems (ABSs) comprising the low cytotoxic butylguanidinium chloride ionic liquid (IL) and different salts as a saliva clean-up, microextraction and preconcentration tool. Among the developed and characterized ABSs, the one composed of the IL and K2HPO4 was selected to develop an integrated analytical procedure in saliva. Sample clean-up is achieved by removing 70% of the salivary proteins through precipitation as a solid interphase of the ABS - creating a three-phase partitioning (ABS/TPP) system - while a miniaturized extraction and preconcentration approach is simultaneously performed. The ABS/TPP, together with high-performance liquid chromatography and fluorescence detection (HPLC-FD), was optimized for bisphenols as representative biomarkers in saliva. Optimum conditions included 0.35 g of IL, 0.60 g of salt, 1.1 g of saliva, 1 min of stirring, and centrifugation. The ABS/TPP-HPLC-FD method exhibited enrichment factors up to ca. 3, extraction efficiencies higher than 80.5% despite using a miniaturized technique, and limits of detection down to 0.40 ng mL-1. The inter-day precision, expressed as relative standard deviation, was lower than 9.1%, achieving average relative recoveries of 106%. The method was successfully performed when analyzing male and female saliva. The green nature of the method as compared to other state-of-the-art techniques was demonstrated using several green metrics, scoring 0.63 in AGREEprep. Ionic liquid-based aqueous biphasic systems succeed in one-step clean-up, microextraction, and preconcentration strategies for biomarkers in saliva. These novel platforms improve the saliva bioanalysis in terms of simplicity and greenness.
keywords
ENDOCRINE-DISRUPTING CHEMICALS; 2-PHASE SYSTEMS
subject category
Chemistry; Science & Technology - Other Topics
authors
González-Martin, R; Silva, FAE; Trujillo-Rodríguez, MJ; Diaz, DD; Lorenzo-Morales, J; Freire, MG; Pino, V
our authors
Ana Francisca Osório de Almeida Coelho e Silva
Junior Researcher
Mara Guadalupe Freire Martins
Coordinating ResearcherProjects
CICECO - Aveiro Institute of Materials (UIDB/50011/2020)
CICECO - Aveiro Institute of Materials (UIDP/50011/2020)
Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)
Collaboratory for Emerging Technologies, CoLab (EMERGING TECHNOLOGIES)
acknowledgements
This work was developed within the scope of the project ref. PID2020-115004RB-I00, funded by the Spanish Ministry of Science and Innovation, the project ref. ProID2020010089 of the Research Canary Agency "ACIISI", the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020, UIDP/50011/2020 & LA/P/0006/2020, financed by national funds through the FCT/MEC (PIDDAC), and the project PTDC/EMD-TLM/3253/2020, funded by national funds (OE), through FCT/MCTES. This study was also funded by Consorcio Centro de Investigacion Biomedica en Red (CIBER) de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Spain (CB21/13/00100), Cabildo Insular de Tenerife 2023-2028 and Ministerio de Sanidad, Gobierno de Espana. R. G.-M. thanks the Spanish Ministry of Universities for his FPU fellowship. F. A. e Silva acknowledges FCT - Fundacao para a Ciencia e a Tecnologia, I.P. for the researcher contract CEECIND/03076/2018 under the Scientific Employment Stimulus - Individual Call 2018. M. J. T.-R. thanks her former Excellence Junior research contract with Fundacion La Caixa - Fundacion CajaCanarias, which covered her research stay in Portugal, together with her current Ramon y Cajal contract (ref. RYC2021-032502-I) at Universidad de La Laguna, contract with funding of the Spanish Ministry of Science and Innovation MCIN/AEI/10.13039/501100011033 and the European Union "NextGenerationEU"/PRTR.