https://www.selleckchem.com/products/ide397-gsk-4362676.html The amount of DNA adsorbed on the electrode surface, which corresponds to the DNA methylation level in the sample, was electrochemically estimated by differential pulse voltammetric (DPV) study of an electroactive indicator [Ru(NH3)6]3+ bound to the surface-adsorbed DNA. Using a 200 ng DNA sample, the assay could successfully detect differences as low as 5% in global DNA methylation levels with high reproducibility (relative standard deviation (% RSD) = less then 5% for n = 3). The method could also reproducibly analyze various levels of global DNA methylation in synthetic samples as well as in cell lines. The method avoids bisulfite treatment, does not rely on enzymes for signal generation, and can detect global DNA methylation using clinically relevant quantities of sample DNA without PCR amplification. We believe that this proof-of-concept method could potentially find applications for liquid biopsy-based global DNA methylation analysis in point-of-care settings.We developed a novel fast gas chromatography (fastGC) instrument with integrated sampling of volatile organic compounds (VOCs) and detection by single-photon ionisation (SPI) time-of-flight mass spectrometry (TOFMS). A consumable-free electrical modulator rapidly cools down to -55 °C to trap VOCs and inject them on a short chromatographic column by prompt heating to 300 °C, followed by carrier gas exchange from air to helium. Due to the low thermal mass and optical heating, the fastGC is operated within total runtimes including cooling for 30 s and 15 s, referring to hyper-fast GC, and at a constantly increasing temperature ramp from 30 °C to 280 °C. The application of soft SPI-TOFMS allows the detection of co-eluting VOCs of different molecular compositions, which cannot be resolved by conventional GC (cGC) with electron ionisation (EI). Among other analytical figures of merit, we achieved limits of detection for toluene and p-xylene of 2 ppb a