Calibration Requirements for Inorganic Analyses
Effective Date: 08/06
Point of Contact: Quality Engineer for Regulatory Programs
| Instrument or Test | Calibration Criteria | Frequency | Acceptance Criteria | Failure Action |
|---|---|---|---|---|
| Inductively coupled plasma spectrometer | Profile Blank and one concentration per analyte of interest | Before each new analytical run(a) | Meet manufacturer's recommendation for peak centroid and full width at half max. A calibration verification standard within ±10% of true value confirms acceptability of calibration | Investigate. Correct. Recalibrate, as required. |
| ICP/mass spectrometer (MS) | Tune Check mass calibration Calibrate using at least a blank and one standard according to manufacturer's recommendations. |
Analyze four times. Before each analytical run. |
RSD ≤5% Mass calibration must be less than 0.1 amu of actual value. Resolution must be less than 0.9 amu full widths at 10% peak height. Calibration verification within ±10% of true. |
Investigate. Correct. Adjust mass calibration to correct value. Investigate. Correct. Recalibrate. |
| Atomic absorption: graphite furnace or flame | Blank and three concentrations per analyte of interest, working range | Before each new analytical run(a) | Calibration curve must have correlation coefficient > 0.995. A mid-range calibration verification standard within ±10% of true value confirms acceptability of calibration | Investigate. Correct. Recalibrate, as required. |
| Cold Vapor Mercury | Blank and 4 standards | Before each new analytical run | Calibration curve must have a Correlation of Coefficient > 0.995. A Midrange calibration verification standard within ±20%. | Investigate. Correct. Recalibrate, as required. |
| Cyanide (spectrophotometric) | Blank and three concentrations (undistilled) to define the working range | Before each new analytical run(a) | Calibration curve must have a correlation coefficient > 0.995. A distilled mid-range calibration verification standard within ±15% of true value confirms acceptability of calibration | Investigate. Correct. Recalibrate, as required. |
| Ion chromatography | Blank and three concentrations to define the working range | After major maintenance or upon failure of the calibration verification | Calibration curve must have a correlation coefficient >0.995. A mid-range calibration verification standard within ±10% of true value confirms acceptability of calibration | Investigate. Correct and recalibrate, as required. |
| pH | Two-point calibration; 3 pH units or more apart calibration range representative of sample results. Note: For corrosivity characterization, one buffer should be a pH of 2 for acidic wastes and pH of 12 for caustic wastes. | Before each new analytical run(a) | For dial or slope calibration, analysis of calibration standards must measure within 0.05 pH units of true value A calibration verification standard within 0.1 pH units of true value confirms acceptability of calibration | Investigate. Correct. Recalibrate, as required. |
| ISE Working curve |
Minimum of 3 concentrations, with one near the MDL, to define the working range | Before each new analytical run(a) | A mid-range calibration verification standard within ±10% of true value confirms acceptability of calibration | Investigate. Correct. Recalibrate, as required. |
| ISE Known Addition, etc. | Follow manufacturer's recommendations. | All samples, standards and blanks | Calibration verification within ± 3 standard deviation of the historical mean | Investigate. Correct. Recalibrate, as required. |
| Colorimetric analyses (excluding cyanide) | Blank and a minimum of 3 concentrations, with one near the MDL, to define the working range | Before each new analytical run(a) | A mid-range calibration verification standard within ±10% of true value confirms acceptability of calibration | Investigate. Correct. Recalibrate, as required. |
| Titrimetric | N/A | N/A | Standardize titrants before use. Evaluate results based on QC performance. | Investigate. Correct. Recalibrate, as required. |
(a) Analytical run is defined as sequence of analyses within a continuous time period.
ISE = Ion selective electrode
MDL = Method detection limit.