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NIST websites for programs using non-appropriated funds (NVLAP and PSCR) or those that are excepted from the shutdown (such as NVD) will continue to be available and updated.
The mass spectrum for the synthetic opioid fentanyl. The mass spectrum is like a molecular fingerprint, and is used to identify unknown compounds. The red lines represent the charged fragments of the molecule created during analysis. The vertical axis shows the relative intensity, or amount, of each fragment, while the horizontal axis shows the mass-to-charge ratio for each fragment.