Development of a maleic acid-based material to selectively solid-phase extract basic compounds from environmental samples

This study presents a novel mixed-mode weak cation-exchange (WCX) material. This material was prepared by means of the functionalization of a mesoporous divinylbenzene (DVB) resin with maleic acid (maleic acid-DVB), which yielded a high carboxylic moiety content resulting in WCX interactions as well as suitable specific surface area for reversed-phase interactions. After the optimization of the solid-phase extraction (SPE) protocol to enhance the selectivity of the sorbent, this material was evaluated as a novel WCX sorbent in the SPE of a group of drugs from environmental water samples. The method is based on SPE followed by liquid chromatography (LC) coupled to high resolution mass spectrometry (HRMS) with an Orbitrap analyzer, and was validated and applied for the determination of basic drugs in river, effluent and influent wastewater samples. Maleic acid-DVB sorbent yielded suitable recovery rates (57% to 89%) and an acceptable matrix effect (<32%) thanks to the effective washing step included when these environmental waters were loaded through the novel resin. The method was applied to different environmental water samples and some basic drugs were suitably quantified in these environmental samples.

1200 Seasonal Variation In RHR Measured By A Wearable Ring

Introduction

Resting heart rate (RHR) associates with cardiovascular fitness, acute and chronic health status, and mental stress. Nightly sleep provides an excellent measurement time because ambient conditions are constant and confounding factors are controlled. Relatively low RHR is seen as a mark of better health, performance, and recovery levels. Over the past few years, development of wearable devices has made it possible to follow the course of individual RHR as long-term time series, which enables observation of how behavioural, societal and seasonal factors affect RHR at population scale.

Methods

In this study, mean individual nightly RHR of each calendar day was studied from all Oura ring users starting from July 2016 (n=1415) and ending at March 2019 (n=57.278). The subjects were 36 percent female and 64 percent male, mostly in working age: 20-30-year (15%), 30-50 years (60%), and 50-60-years (16%). Majority of the ring users live in the Northern Hemisphere, and minority (n = 1.500) in the Southern Hemisphere.

Results

With users from Northern Hemisphere, the yearly RHR peaks in December and lowers between April and August. The magnitude of seasonal variation was observed to be roughly 2 bpm: In 2018, March averages 1.6 bpm higher than August, and December averages 2.1 bpm higher than August. Looking at subjects from New Zealand and Australia, exactly opposite phase was observed, so that both hemispheres followed the length of the day. Apparently, RHR yearly fluctuations are based on biological factors like Sun light and ambient temperature. Both hemispheres also demonstrated weekly peaks at weekends (+1.6 bpm), and a most district peak at each New Year night.

Conclusion

The long-term RHR was shown to be affected by biological, societal, and lifestyle factors. We find that long-term wearable data from the Ring can reveal health related physiological effects across large populations, including seasonality.

Support

This work was supported by Oura Health Ltd.