A shell of SiO2 with tunable thickness was uniformly coated on NaGd(WO4)2:Yb3+/Er3+ core upconversion nanoparticles (UCNPs). The effects of the silica shell on UC luminescence and thermal sensing properties of the core–shell UCNPs were investigated.

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As an important storage medium of semi-volatile organic compounds (SVOC) in indoor environments, house dust has been extensively used to assess the pollution level of indoor SVOC. SVOC in house dust are commonly quantified using solvent-extraction methods, which are however solvent-consuming, time-consuming and laborious. Thermal desorption (TD, solvent-free and easy-to-use) is a good alternative to solvent extractions, but its performance for analyzing house dust is still unverified. Therefore, we proposed a TD-based method for quantifying SVOC in house dust by incorporating the TD technique with GC-MS. Laboratory experiments (48 samples with high SVOC concentrations) and field-test experiments (12 samples with low SVOC concentrations) were performed to justify the proposed method by comparing its results to those of a traditional solvent-extraction method (Soxhlet extraction). For laboratory dusts, the accuracy (relative deviation < 20%) and repeatability (relative standard deviation < 13%) of the TD-based method were comparable to the solvent-extraction method. For field-test dusts, higher SVOC concentrations were typically obtained by the TD-based method, implying its superior performance. These results gave evident confidence in the performance of the TD-based method, which facilitated the simple, solvent-free and accurate quantification of SVOC in house dust.

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