HPLC-CAD as a supplementary method for the quantification of related structure impurities for the purity assessment of organic CRMs.

In organic purity assessment, chromatography separation with a suitable detector is required. Diode array detection (DAD) has been a widely used technique for high-performance liquid chromatography (HPLC) analyses, but its application is limited to compounds with sufficient UV chromophores. Charged aerosol detector (CAD), as a mass-dependent detector, is advantageous for providing a nearly uniform response for analytes, regardless of their structures. In this study, 11 non-volatile compounds with/without UV chromophores were analyzed by CAD using continuous direct injection mode. The RSDs of CAD responses were within 17%. For saccharides and bisphenols, especially, the RSDs were lower (2.12% and 8.14%, respectively). Since bisphenols exist in UV chromophores, their HPLC-DAD responses were studied and compared with CAD responses, with CAD showing a more uniform response. Besides, the key parameters of HPLC-CAD were optimized and the developed method was verified using a Certified Reference Material (CRM, dulcitol, GBW06144). The area normalization result of dulcitol measured by HPLC-CAD was 99.89% ± 0.02% (n = 6), consistent with the certified value of 99.8% ± 0.2% (k = 2). The result of this work indicated that the HPLC-CAD method could be a good complementary tool to traditional techniques for the purity assessment of organic compounds, especially for compounds lacking UV chromophores.

Calculation and Experimental Validation of a Novel Approach Using Solubility Parameters as Indicators for the Extraction of Additives in Plastics.

Accurately quantifying chemical additives with adverse health effects in plastic products is critical for environmental safety and risk assessment. In this work, a novel approach using solubility parameters (δ) as indicators for the extraction of additives in plastics was developed. The mechanism was evaluated by using 10 organic solvents with different solubility parameters to extract brominated flame-retardant-decabrominated diphenyl ether (BDE-209) in polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET). Certified reference materials (CRMs) or CRM candidate materials were applied as matrix materials. The extracted BDE-209 and solubility parameters of solvents could fit into a curve of a quadratic function. The value of abscissa corresponding to the vertex of the function was close to the solubility parameter of plastic calculated by the group contribution method (Δδ < 0.37). Toluene, n-hexane, and acetone were the solvents with high extraction efficiency for PE, PP, and PET, confirming the feasibility of the developed approach. The results of ethyl acetate and acetone indicated the high weight of functional groups affecting the dissolution behavior. The developed approach was further verified by analyzing penta-/octa-BDE and phthalate esters in PET and polyvinyl chloride (PVC) and finally applied to analyze 15 plastic products made of PP, PE, PET, polystyrene, and PVC. The detected tetrabromodiphenyl ether (BDE-47), BDE-209, decabromodiphenyl ethane, and di(2-ethylhexyl) terephthalate all matched the approach and verified its practicability for field sample analysis.

Correction: Liao et al. Twelve-Week Lower Trapezius-Centred Muscular Training Regimen in University Archers. Healthcare 2022, 10, 171.

The authors would like to make the following corrections to the published paper [...].

Twelve-Week Lower Trapezius-Centred Muscular Training Regimen in University Archers.

Archery is a fine-motor-skill sport, in which success results from multiple factors including a fine neuromuscular tuning. The present study hypothesised that lower trapezius specific training can improve archers' performance with concomitant changes in muscle activity and shoulder kinematics. We conducted a prospective study in a university archery team. Athletes were classified into exercise and control groups. A supervised lower trapezius muscle training program was performed for 12 weeks in the exercise group. The exercise program focused on a lower trapezius-centred muscular training. Performance in a simulated game was recorded as the primary outcome, and shoulder muscle strength, kinematics, and surface electromyography were measured and analysed. In the exercise group, the average score of the simulation game increased from 628 to 639 after the training regimens (maximum score was 720), while there were no such increases in the control group. The lower trapezius muscle strength increased from 8 to 9 kgf after training regimens and shoulder horizontal abductor also increased from 81 to 93 body weight% for the exercise group. The upper/lower trapezius ratio decreased from 2.2 to 1.1 after training. The lower trapezius exercise training regimen could effectively improve the performance of an archer with a simultaneous increase in shoulder horizontal abductor and lower trapezius muscle strength.