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Error Rates and Drift in Precision

Purpose: To establish that the ASTC/CFS is not sampling from aging instruments out in the field tpo determine error rates To establish that the ATC/CFS is not allowing for drift in precision of instruments as they age without re-calibration To suggest possible acceptable or normal error rates #errorrate #sampling #drift

Control Tests do not displace Formal Calibration Intervals

Purpose: To separate conceptually control tests from calibration To obtain an admission that there are no "assessors" in the province of Ontario To obtain an admission that the historical maintenance records show a deterioration of performance - deterioration of linearity in this particular instrument The strategy of using control tests as indication of reliability depends upon completeness of records and transparency To obtain an admission that at the bottom of the valley in the infrared spectrum at approximately 9.4 microns, your detection limit will certainly be degraded and precision will also suffer in most instances, if you are no longer taking the reading at the absorbant’s maximum. T

R. v. Vallentgoed Distinguished on facts - Short Calibration Interval

Purpose: To obtain admissions from the Crown expert to enable argument that Vallentgoed can be distinguished on its facts - particularly respecting: - recent re-calibration on a regular calibration interval - calibration by a service provider independent of the police #Vallentgoed #calibrationinterval #inspection

Short Calibration Interval and Reliability

Purpose: To introduce the concept of "calibration interval" To obtain admissions as to the importance of calibration interval in the international scientific literature To obtain an admission that neither the ATC/CFS nor the manufacturer mandate a calibration interval for approved instruments, though the manufacturer so specifies for ASDs To introduce some international standards on reliability including ISO 17025 To introduce the concept of "uncertainty growth" To connect "reliability", "calibration interval", and "uncertainty growth" "over time" #uncertaintygrowth #calibrationinterval #reliability #overtime

Instrumental Deviations from Beer-Lambert Law

Purpose: To explore the reasons why measurement instruments in the field may deviate from the linearity alleged by the Beer-Lambert law To introduce a university textbook dealing with inter alia: External Calibration Creating a Calibration Curve Limits to Beer's law No longer linear when the molar absorptivities differ Instrumental Deviations from Beer-Lambert law Polychromatic Radiation rather than Monochromatic IR #BeerLambert #polychromatic #linearity #calibrationcurve #calibration

Bandwidth of Filters Changes Over Time

Purpose: To explain the basic methodology of IR quantitative analysis using an approved instrument. To explain calibration. To explain the function of the linearizer. To explain drift over time. To explain calibration curve. The pencil is the sample in the sample chamber. The paperclips are the instrument's electronic response to the transmittance of IR light through the sample chamber. An electrical signal is produced by the detector at the end of the sample chamber that has a relationship to transmittance. The instrument has been calibrated at the factory such that the calibration curve recorded in the instrument's calibration software settings says 4 paperclips = 2 gms and 2 paperclips =

Beer-Lambert Law as Stated in Training Aid is Over-Simplified and Inadequate

Purpose: To obtain admissions that the concept of single point control test(s) at time of use is adequate, to verify calibration has not changed over time, is not good measurement science. To obtain admissions that checks of linearity during annual maintenance or other periodic inspection are necessary to confirm linearity, to confirm that the instrument is still calibrated across the whole measuring interval. To obtain an admission that although the Beer-Lambert Law suggests that the relationship between concentration in the sample chamber and the measurement result is linear (after adjusting for the logarithmic relationship of absorption/transmittance) is linear, there are instrumental dev

The "known" is the original calibration of the instrument

Purpose: To separate the concepts of "calibration" from "control checks" To clarify that "calibration" is something that happens at the factory, not at time of use by a qualified technician To clarify that control tests at time of testing are simply a verification (to use the CFS scientist's words) that calibration hasn't changed over time (note Hodgson concept of "over time" in his paper referred to in St-Onge) #calibration #controltest #verification #overtime

Traceability of a Measurement Result

Purpose: To educate the Court about the meaning of "traceability" in measurement science. To obtain an admission that there is a relationship between the calibration certificate (Certificate of Calibration) from the factory and the reference standards used during the factory calibration. To obtain an admission that there is a relationship between the calibration certificate from the factory and the scientific reliability of the measurement result at time of use. To introduce the NIST Certificate for the reference standards used at the time of calibration at the factory. #traceability #certificateofcalibration #referencestandard #NIST

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Intoxilyzer®  is a registered trademark of CMI, Inc. The Intoxilyzer® 5000C is an "approved instrument" in Canada.

Breathalyzer® is a registered trademark of Draeger Safety, Inc., Breathalyzer Division. The owner of the trademark is Robert F. Borkenstein and Draeger Safety, Inc. has leased the exclusive rights of use from him. The Breathalyzer® 900 and Breathalyzer® 900A were "approved instruments" in Canada.

Alcotest® is a registered trademark of Draeger Safety, Inc. The Alcotest® 7410 GLC and 6810 are each an "approved screening device" in Canada.

Datamaster®  is a registered trademark of National Patent Analytical Systems, Inc.  The BAC Datamaster® C  is an "approved instrument" in Canada.