Investigating ear at molecule level is challenging task, since there is a lack of molecular detection by traditional diagnosis techniques such as otologic endoscopy, ear swab culture, and imaging diagnostic technique. Therefore, new development of noninvasive, highly sensitive, and convenient analytical method for investigating human ears is highly needed. We developed a wearable sampling device for extracting trace analytes in ear by fixing solid-phase microextraction fibers into modified earmuffs (SPME-in-earmuffs). After sampling, SPME fiber was coupled with gas chromatography-mass spectrometry (GC-MS) for identification and quantification of extracted analytes. Enhanced detection of various analytes such as volatile metabolites, exposures, and therapeutic drugs of ears were demonstrated in this work. Particularly, sport-induced metabolic changes such as fatty acids, aldehyde compounds and oxidative produces were found from human ears using this method. Acceptable analytical performances were obtained by using this newly developed method for detecting ear medicines, e.g., low limit of detection (LOD, 0.005–0.021 ng/mL) and limit of quantification (LOQ, 0.018–0.071 ng/mL), excellent linear dynamic responses (R > 0.99, ranging from 0.050–8.00 ng/mL), good relative standard deviations (RSDs, 13.19 % ∼ 21.40 %, n = 6) and accuracy (84.43–150.18 %, n = 6) at different concentrations. For the first time, this work provides a simple, convenient, and wearable microextraction method for enhanced detection of trace volatiles in human ears. The enclosed space between ear and earmuff allows headspace SPME sampling of volatile analytes, and thus provides a new wearable method for monitoring ear metabolites and human exposures, showing potential applications in human health, disease diagnosis, and sport science.

中文翻译：

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可穿戴式固相微萃取采样，用于增强人耳中挥发性分析物的检测


在分子水平上研究耳朵是一项具有挑战性的任务，因为传统的诊断技术（如耳科内窥镜、耳拭子培养和影像诊断技术）缺乏分子检测。因此，迫切需要开发新的非侵入性、高灵敏度、方便的分析方法来研究人耳。我们开发了一种可穿戴采样装置，通过将固相微萃取纤维固定到改良耳罩（SPME-in-earmuffs）中来提取耳中的痕量分析物。采样后，SPME 纤维与气相色谱-质谱 (GC-MS) 结合，对提取的分析物进行鉴定和定量。这项工作证明了对各种分析物（如挥发性代谢物、暴露物和耳朵治疗药物）的增强检测。特别是，使用这种方法从人耳中发现了运动引起的代谢变化，例如脂肪酸、醛类化合物和氧化产物。使用这种新开发的耳科药物检测方法获得了可接受的分析性能，例如低检测限（LOD，0.005–0.021 ng/mL）和定量限（LOQ，0.018–0.071 ng/mL）、出色的线性动态不同浓度下的响应（R > 0.99，范围为 0.050–8.00 ng/mL）、良好的相对标准偏差（RSD，13.19 % ∼ 21.40 %，n = 6）和准确度（84.43–150.18 %，n = 6）。这项工作首次为人耳中微量挥发物的增强检测提供了一种简单、方便、可穿戴的微萃取方法。 耳朵和耳罩之间的封闭空间允许对挥发性分析物进行顶空固相微萃取采样，从而为监测耳朵代谢物和人体暴露提供了一种新的可穿戴方法，显示出在人类健康、疾病诊断和运动科学中的潜在应用。