Limit groups
A limit group is a named set of limits for samples that should be judged the same way (a regulation, a matrix, a client). A sample has at most one limit group. The catalog is Limit groups in the method editor and in the navigator.
What a group holds
Each limit row is one limit group × one analyte name, and optionally one quant key.
Analyte-level row (quant key empty). These apply to the reported value:
- Concentration too low
- Concentration too high
- Minimum recovery %
- Maximum recovery % (also the window for a continuing calibration verification; see Continuing calibration verification)
- Final concentration multiplier (default 1, applied after dilution)
On an ISTD analyte, the recovery window is also the ISTD response deviation window.
The quant-level fields on this same row are the default for every quant of that analyte.
Quant-level row (quant key filled in). Only these fields are read, and a filled value replaces the analyte-level default for that quant:
- Minimum and maximum response
- Unexpected quant peak height
- Minimum Q value (0–100)
- Minimum number of passed qualifiers
- Maximum number of failed qualifiers
- Minimum curve R²
A blank number means that check is off. See Checks for how each one is judged.
The limit-group catalog row also holds the CCV sequence settings for samples in that group:
- MaxCcvGap — maximum injections between CCV vials. Empty turns the interval check off.
- CloseCcv — Sample and QC results after the last CCV are flagged when this is on.
Those two live on View → Limit groups, on the group the Sample and QC vials use, so every analyte in the group shares one interval. The CCV recovery window is Min recovery and Max recovery on the CCV’s own limit group.
Quanto does not store separate columns named LOD, LOQ, or MRL. Use concentration too low / too high, or the response limits, for those reporting and detection cutoffs. The final-concentration multiplier is the extra scale for that group and analyte.
Assigning samples and analytes
Put the group name on the sample (Limit group). The analyte side is the analyte name on the limit row, not a second assignment on the analyte. One analyte name can have different numbers in different groups. One sample uses one group, so every analyte in that sample is judged with that group’s rows.
Rename a group and the samples that used the old name follow. Delete a group and its limit rows are removed and the sample labels are cleared.
New groups are named with the next free number (1, 2, 3, …) until you rename them. Each group has a display color.
How limits are evaluated and shown
Quantitate copies the analyte-level limits onto the batch and evaluates the flags. Concentration outside the low/high limits sets the concentration flag. Recovery outside the window sets the recovery flag. R² below the minimum sets the R² flag to too low. The other quant-level fields set their own flags (response, Q value, qualifier counts, unexpected height).
Flags appear on the result and in the Outliers text. Grids and review tiles color too low, OK, and too high. Reports read the same fields.
The curve fit is shared. The minimum R² can differ per sample because each sample brings its own group’s cutoff.
Relation to other groups
A limit group does not choose the curve, the dose, or the calibration bracket. Doses supply the known concentration for recovery. Cal group Mode chooses spike recovery on a normal curve or standard addition. Sample groups and analyte groups are filters. See Doses, Bracketing, Sample groups, and Analyte groups.