Spectrum workbench

Signum

Open NMR, IR, Raman, UV-Vis and mass spectra right in the browser. Pick peaks, integrate and read ¹H multiplets, correct the baseline, overlay spectra and export CSV, Excel or JCAMP-DX.

  • Files are read on this computer and never uploaded
  • JCAMP-DX with every compression, Galactic SPC, CSV, TSV and XY
  • Integrals, multiplicity and J in the journal format
  • Overlay spectra of the same kind and compare them

Drop a spectrum here

JCAMP-DX, SPC, CSV or XY. Several files open as overlays.

Or open an example

Ethanol¹H NMR · 300 MHz, CDCl₃ Quinine¹H NMR · 65 536 points, shifts in Hz BenzeneIR · gas, Coblentz 8861 TolueneIR · gas, Coblentz 8882 AcetoneIR · gas, NIST quantitative TolueneUV-Vis · log ε, 234–275 nm Tannic acidRaman · Ocean Optics R2000 EthanolMS · EI, NIST FT-IR exampleIR · Galactic SPC, transmittance
What Signum reads

JCAMP-DX 4.24, 5.00 and 5.01, the IUPAC recommendation of 1999, in every data form: plain AFFN and the compressed SQZ, DIF, DUP and PAC forms, alone or combined as DIFDUP, with the Y relay check on every DIF line verified. XYPOINTS, PEAK TABLE and PEAK ASSIGNMENTS blocks are read, link and compound files keep the spectrum together with its peak table, and NTUPLES files show every page they hold: real beside imaginary, 2D PROFILE pages and LC-MS or GC-MS spectral series as peak lists. NMR shifts stored in Hz are converted to ppm with the observe frequency.

Galactic SPC in the new format, little- and big-endian, and in the old 0x4D format; 16-bit and 32-bit fixed point or IEEE float; evenly spaced, one shared X array or an X array per subfile with its directory; one or many subfiles, with the instrument log. Text as CSV, TSV or whitespace columns, with or without a header, with a decimal point or a decimal comma.

Files are read as UTF-8, as UTF-16 with or without a byte order mark, and as Windows-1252 when the file is neither; the code page that was assumed is shown with the spectrum. A damaged file is read up to the damage: the missing points, the broken line checks and the byte offset are named, and everything before them is kept.

Peaks, integrals and multiplets

Peaks are local maxima whose prominence clears a threshold and the noise level; transmittance spectra are picked at their minima. Positions are refined with a parabola through the top three points. Click a peak to label it or drag across a region to pick every peak in it.

Integrals are trapezoid areas over the range you drag. Type a number of protons into any integral and the others follow. For ¹H spectra each range is read as a multiplet: it is only named d, t, q, dd, dt or td when the lines are equally spaced as that pattern requires and their intensities match; everything else is reported as m with its range. J comes from the line spacing in Hz, so it is only as good as the digital resolution. The report is written in the format journals ask for.

Processing

Savitzky–Golay smoothing, baseline correction by asymmetric least squares or an iterative polynomial, transmittance to absorbance, wavenumber to wavelength and ppm to Hz. The file itself is never changed: exports contain the processed data and a JCAMP-DX export records the steps in a DATA PROCESSING line.

Where your data goes

Nowhere. Files are read and processed in your browser, and nothing is sent to a server. Closing the tab discards them. What the site itself records is on the privacy page.