口臭试金石

Litmus test

Need a quick breath check before your big meeting or your big date? Well, scientists from South Korea may be able to help. They’ve engineered a portable device that detects even the tiniest trace of hydrogen sulfide the stuff that smells like rotten eggs that is one of the primary offenders in oral obnoxiousness. Their work appears in the journal Analytical Chemistry.

Bad breath, a.k.a. halitosis, can be more than a social inconvenience. A skunky mouth also may point to some serious underlying medical or dental issues.

“Early diagnosis is very significant to prolong your healthy life.” Jun-Hwe Cha of the Korea Advanced Institute of Science and Technology. He says that most of the instruments used for diagnostics are found in clinics or hospitals, which may be tough to get to. And the electronic sensors that are currently used to sniff out various gases require a power source and precise calibration not easy when you’re out and about.

“So, we came up with a strategy to develop colorimetric gas sensors, which change its color when detecting biomarker gases.” Think of it as a litmus test for your exhalation.

To build their sensor, the researchers took lead acetate, a chemical used in some hair dye products that turns brown when exposed to hydrogen sulfide. And they embedded it in a three-dimensional nanofiber web, so the dye would spread out across a large surface area. That distribution gives the sensor the sensitivity it needs to detect trace amounts of H2S.

To test the device, the researchers puffed it with different concentrations of hydrogen sulfide gas. And they found that as little as 400 parts per billion of H2S produced a color change that could be seen by the naked eye. Which is about a fifth as much H2S as you’d need to have stank breath.

They even used the device with real human outgassing. The researchers had volunteers blow into a bag. And they spiked these exhalates with 1,000 parts per billion H2S. Again, the bad-breathylizer worked like a charm. “This sensor showed high potential for simple halitosis diagnosis with your breath anytime anywhere in a very short time.”

The team is now working on similar diagnostic sensors for other vaporous effluvium. It may not sound pretty. But, hey, it’s a gas.

参考译文

需要在大型会议或重要约会之前快速测口气吗?来自韩国的科学家或许能帮上忙。他们设计了一种便携式设备,哪怕是微量的硫化氢都能检测出来,硫化氢是一种臭鸡蛋味气体,口臭的罪魁祸首。这项研究发表在分析化学杂志上。

口腔异味,又称口臭,可不只是社交缺陷,口臭还表明身体可能出现一些严重疾病或牙科问题。

早期诊断口臭对保持健康非常重要,韩国科技院的一名科学家表示,现在大多数诊断仪器都用于诊所或医院,日常使用较少。目前用于气体检测的电子传感器需要电源和精确校准,不便于户外使用。

因此我们提出了一个方法,开发比色气体传感器。当检测到生物标记气体时,传感器就会改变颜色。我们可以把它看成一张测口气的石蕊试纸。

研究人员采用醋酸铅制作传感器,醋酸铅是在一种染发产品中常用的化学物质,遇硫化氢呈褐色。他们把醋酸铅嵌入三维碳纤维网中,这样染料就会大面积扩散,提高传感器灵敏度,从而测出微量硫化氢。

研究人员将不同浓度的硫化氢气体吹向该装置,对其进行测试。他们发现,浓度低到到十亿分之四百的硫化氢都能使其产生肉眼可见的颜色变化。这大约是闻到口臭所需硫化氢浓度的五分之一。

他们还使用了真正的人类口气进行测试。研究人员请志愿者往袋子里吹气,然后将这些呼出气体与浓度十亿分之一千的硫化氢混合。结果一样,呼吸检测效果立竿见影。科学家说,这种传感器口臭检测能力突出,随时随地,快速诊断。

研究小组目前正在研发类似传感器,诊断其它臭气,可能不太中听,不过还挺有趣。

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