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OpenReadout

MicroCal ITC .itc

MicroCal isothermal titration calorimeters (VP-ITC, iTC200, and PEAQ-ITC through its .itc export) save each run as an .itc raw data file. OpenReadout returns the thermogram (differential power and cell temperature over time), the injection table and the run settings: concentrations, cell volume, temperature, stirring and reference power. Derived from public files of four depositors (VPViewer2000, ITC200 and MicroCal ITC software), Origin’s raw and integrated-heat exports of some of them, and the depositors’ notebooks and file names. Provenance: docs/provenance/microcal-itc.md. Crate: openreadout-biophys.

format id files reads confidence
microcal-itc .itc raw data files of MicroCal VP-ITC, iTC200 and the MicroCal ITC software (also what PEAQ-ITC exports as .itc) the thermogram, the injections, concentrations, cell volume, temperature, stirring, reference power, instrument and software medium (evidence rubric, docs/assurance.md)

Not read: PEAQ-ITC native .apitc files and analysis projects (.apj), Origin projects (.opj), NITPIC/SEDPHAT files. Integrated injection heats are the analysis software’s (its baseline and integration) and are not stored in .itc files.

Layout

Text (CRLF; Latin-1 is accepted). Line prefixes:

prefix lines our reading
$ ITC; the number of injections; NOT (kept verbatim); the target temperature (°C); the initial delay (s); the stirring speed (rpm); the reference power (µcal/s); a code (kept); ADCGainCode: n; three booleans (kept); then one line per injection: volume (µl), duration (s), spacing (s), filter period (s) method
# 0; syringe concentration (mM); cell concentration (mM); cell volume (ml); temperature (°C); two further numbers (kept) concentrations, cell volume
? starts the operator’s comment, which runs until the first % line comment
% the instrument identifier (VPITC…, ITC200_…, MICROCALITC_…); the cell volume; calibration numbers (kept verbatim, not interpreted); last, the software and version (VPViewer2000 Ver: 1.4.8, ITC200 Ver: 1.26.1, MicroCalITC Ver: 1.29.32 Run time:…) instrument, software
@0 starts the pre-injection baseline
@n,v[,d[, t]] starts injection n’s data block (volume v µl, duration d s, and in newer files the time t s the injection started) injection table
digits a data row: time (s), differential power (µcal/s), cell temperature (°C), and in newer files 4 or 6 further columns thermogram

What the reader returns

  • Trace 0 thermogram (one sweep): channel 0 differential_power (µcal/s), channel 1 cell_temperature (°C), then column_4 … column_9 (unnamed further columns, no unit) when the file has them. Sampling is uniform in every file seen (2 s, 1 s or 5 s): sample_rate_hz and start_s give the time (extra.axis = time in s); if a file’s time column is uneven it becomes channel 0 time (s) instead and check says so. extra.kind = thermogram.
  • Table 0 injections: injection (1-based), volume (µL), duration (s), spacing (s), filter_period (s), start (s: the block line’s time, else the block’s first sample time), first_sample (index into the trace).
  • Experiment: instrument vendor Malvern Panalytical (MicroCal), model VP-ITC, iTC200 or MicroCal ITC from the identifier, kind calorimeter (OBI:0000930), software and version; method technique isothermal titration calorimetry (CHMO:0000683) with cell_concentration, syringe_concentration (mM), cell_volume (mL), temperature (°C), initial_delay (s), stirring_speed (rpm), reference_power (µcal/s), injections; acquisition.comment (the ? text) and duration_s (the last sample’s time). The Run time text of the MicroCal ITC software line is kept in the vendor tree (local time without a zone, not an acquisition time).
  • check: the declared number of injections against the listed injection lines and the data blocks (a run that stopped early is a warning), unparseable lines, non-finite values.

Validation

cargo test -p openreadout-corpus-tests --features corpus (tests/itc_oracle/mod.rs): time and differential power equal Origin’s raw exports of three runs at 256 rows each (to the export’s five decimals, over 1,350-6,062 samples), the injection volumes and cell concentration equal Origin’s integrated-heat tables of four runs, and the concentrations match the depositors’ file names and notebooks for three; the other files are checked for internal consistency. One further depositor’s file is held out.

Vocabulary (public API of openreadout-biophys, ITC)

identifier meaning
ItcReader reader of MicroCal .itc files
ITC_FORMAT_ID microcal-itc
ItcDataset the dataset the reader returns

How this reader was derived, file by file: provenance log.