Using his contacts he obtained raw DCA, then asked a chemist friend to buffer it and check its purity.

通过联系，他得到的是未加工的DCA，然后找化学专业的朋友为DCA进行中和并检查其纯度。

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If it seems off, and yet the label claims it is pure, there are a few simple tests you can run to check the purity of the honey.

如果买来的蜂蜜看起来像是、标签上也强调那是纯正的，你可以用以下几个简便的方法检测一下那是否真的纯正。

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Check purity of DNA by electrophoresis and spectrophotometric analysis.

电泳和分光光度计检测基因组dna纯度。

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The company of grocers, for instance, deployed "garblers" to sift through batches of imported spices, to check their purity (hence the modern meaning of the word garbled).

BBC: Lessons from history: Can royalty guarantee a free press?