Determination of low carbon aldehydes and ketones in cigarette smoke by MXene membrane enrichment-liquid chromatography.

Low carbon aldehydes and ketones are typical substances harmful to human body produced during cigarette smoking. Their contents in cigarette smoke are important indicators for evaluating its toxicity and the filtration effect of cigarette filter tips, which provides important guidance for its rational design. In this work, MXene membrane with unique lamellar structure was synthesized and loaded onto glass fiber filters to achieve effective enrichment of low carbon aldehydes and ketones. Compared to commercial Cambridge filters, the MXene-loaded filters exhibited higher extraction efficiency towards low-carbon aldehydes and ketones, making viable the detection of butyraldehyde, which was not detected by that enriched with Cambridge filters. Therefore, a MXene-based membrane enrichment-HPLC method was developed for the determination of low-carbon aldehydes and ketones in cigarette smoke with detection limits ranging from 0.133 µg/mL to 0.285 µg/mL. The applicability of the method was verified by analyzing three different types of filter cigarettes with the concentration in the range of 0.5-140 µg/branch for all the analytes, which were in good agreement with the manufacturer's results. The method is accurate and sensitive, and can be used for the quantitative determination of low carbon aldehydes and ketones in cigarette smoke.

Postoperative plasma copeptin levels independently predict delirium and cognitive dysfunction after coronary artery bypass graft surgery.

Copeptin can reflect individual's stress state and are correlated with poor outcome of critical illness. The occurrence of postoperative delirium (POD) and cognitive dysfunction (POCD) is associated with worse outcome after coronary artery bypass graft (CABG) surgery. The present study aimed to investigate the ability of postoperative plasma copeptin level to predict POD and POCD in patients undergoing CABG surgery. Postoperative plasma copeptin levels of 108 patients were measured by an enzyme-linked immunosorbent assay. It was demonstrated that plasma copeptin levels were substantially higher in patients with POD than without POD (1.8±0.6 ng/mL vs. 1.1±0.3 ng/mL; P<0.001) and in patients with POCD than without POCD (1.9±0.6 ng/mL vs. 1.1±0.4 ng/mL; P<0.001). Plasma copeptin level and age were identified as independent predictors for POD [odds ratio (OR), 67.386; 95% confidence interval (CI), 12.031-377.426; P<0.001 and OR, 1.202; 95% CI, 1.075-1.345; P=0.001] and POCD (OR, 28.814; 95% CI, 7.131-116.425; P<0.001 and OR, 1.151; 95% CI, 1.030-1.285; P=0.003) using a multivariate analysis. For prediction of POD, the area under receiver operating characteristic curve (AUC) of the copeptin concentration (AUC, 0.883; 95% CI, 0.807-0.937) was markedly higher than that of age (AUC, 0.746; 95% CI, 0.653-0.825; P=0.020). For prediction of POCD, the AUC of the copeptin concentration (AUC, 0.870; 95% CI, 0.792-0.927) was markedly higher than that of age (AUC, 0.735; 95% CI, 0.641-0.815; P=0.043). Thus, postoperative plasma copeptin level may be a useful, complementary tool to predict POD and POCD in patients undergoing CABG surgery.