Determination of phenolic compounds in human saliva after oral administration of red wine by high performance liquid chromatography.

Red wine is a relevant source of bioactive compounds, which contribute to its antioxidant activity and other beneficial advantages for human health. However, the bioavailability of phenols in humans is not well understood, and the inter-individual variability in the production of phenolic compounds has not been comprehensively assessed to date. The present work describes a new method for the extraction and analysis of phenolic compounds including gallic acid (Gal), vanillic acid (Van), caffeic acid (Caf), syringic acid (Sir); (-)-epicatechin (Epi); p-coumaric acid (Cum) and resveratrol (Rsv) in human saliva samples. The target analytes were extracted using Fabric Phase Sorptive Extraction (FPSE), and subsequently analysed by high-performance liquid chromatography (HPLC) coupled with photodiode array detector (PDA). Chromatographic separation was achieved using a Symmetry C18 RP column in gradient elution mode, with methanol and phosphate buffer as the mobile phases. The linearity (intercept, slope, and determination coefficient) was evaluated in the range from 1 to 50 µg/mL. The limit of quantification (LOQ) was 1 µg/mL (LLOQ ≥0.8 µg/mL), whereas limit of detection was 0.25 µg/mL. The intra and inter-day RSD% and BIAS% values were less than± 15%. The analytical performances were further tested on human saliva collected from healthy volunteers after administering red wine. To the best of our knowledge, this is the first FPSE procedure for the analysis of phenols in saliva, using a non-invasive and easy to perform sample collection protocol. The proposed fast and inexpensive approach can be deployed as a reliable tool to study other biological matrices to proliferate understanding of these compounds distribution in human body.

Fast off-line FPSE-HPLC-PDA determination of six NSAIDs in saliva samples.

A fast off-line FPSE-HPLC-PDA method has been reported that allows simultaneous clean up and determination of six non-steroidal anti-inflammatory drugs (NSAIDs) in saliva samples from healthy volunteers. Particularly, furprofen, indoprofen, ketoprofen, fenbufen, flurbiprofen, and ibuprofen were chromatographically resolved. Benzyl paraben was chosen as the internal standard (BzPB, IS). These target compounds were successfully extracted from human saliva using fabric phase sorptive extraction (FPSE) and then analysed in the liquid chromatographic system by means of a short analytical column (Symmetry C18, 75 × 4.6 mm, 3.5 µm) using acetonitrile (AcN) and phosphate buffer (PBS, 30 mM; pH = 2.5) as the mobile phases. The method, validated through the calculation of all analytical parameters in accordance of International Guidelines, was applied to real saliva sample analysis collected from informed volunteers. The proposed approach that included the use of sol-gel polytetrahydrofuran (sol-gel PTHF) sorbent immobilized on cellulose support and C18 stationary phase used in HPLC, showed high potential as a fast tool for future clinical and forensic applications. The herein reported results encourage potential future application of FPSE in the forensic field. Furthermore, the FPSE membrane was tested in dried saliva spot mode (DSS) in order to check its potential use as a sampling device, also for forensic applications.

Biofluid sampler: A new gateway for mail-in-analysis of whole blood samples.

The current study reports the development of a novel biofluid sampler (BFS) which is capable of sampling and sample preparation of whole blood without converting it into plasma or serum. The sampler can retain a whole blood sample from 10 to 1000 µL. Although the device shares the same working principle of dried blood spot (DBS) cards, it eliminates most of the technological shortcomings of DBS cards such as low maximum sample volume (~50 µL), sample inhomogeneity due to haematocrit, and poor physical adsorption driven analyte retention by incorporating sol-gel derived high efficiency, multi-functional sorbents on cellulose fabric substrate. The performance of BFS was tested via "Mail-in-Analysis" using three non-steroidal anti-inflammatory drugs (NSAIDs, ketoprofen, carprofen and diclofenac) as the test compounds. Human whole blood samples were fortified with the test compounds and sampled on conventional DBS cards and biofluid samplers (BFSs) in the USA. After drying the blood samples at room temperature, the samples were shipped to Italy for chromatographic analysis. The analytes were back-extracted from the DBS cards and BFSs using methanol and subsequently analysed using a short Symmetry C18 column (75 × 4.6 mm, 3.5 µm). Acetonitrile (ACN) and PBS (30 mM; pH = 2.5) were used as the mobile phases and the elution was performed under isocratic conditions. Compared to the classical dried blood spot cards (DBS), BFSs offer better performance in retaining the selected NSAIDs under conventional postal shipment. By substantially expanding the sampling capacity, eliminating most of the shortcomings of classical DBS cards and exploiting the better materials properties of sol-gel based functional sorbents, BFSs offer a new and profoundly simplified approach for whole blood sampling and analysis and is expected to change the current practice of blood analysis, allowing accurate quantitative analyses either in a local laboratory (on site) or using mail-in-analysis (off site) without compromising the quality of bioanalytical data.