Blog | quantitativeanalysis

May 22, 2018
2 min

Maybe the Instrument Is No Longer Linear Enough to Be An "8000C"

Purpose: To explore the analytical variability of the 8000C as determined by the Alcohol Test Committee during evaluation of the 8000C prior to type approval. To compare the analytical variability of the individual 8000C used in the subject tests for the client with the analytical variability of the type or class 8000C determined by the Alcohol Test Committee. To suggest that the instrument in the matter before the Court may no longer be a member of that class or type because

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BAC Analysis in a Lab Without Bracketing Controls is at Best Qualitative not Quantitative

Stephen Biss

Apr 27, 2018
1 min

BAC Analysis in a Lab Without Bracketing Controls is at Best Qualitative not Quantitative

Purpose: To obtain an admission that when government scientists conduct a quantitative analysis to determine blood alcohol concentration using blood, urine, or serum, they use positive and negative controls. To obtain an admission from the government scientist that when they conduct such quantitative analysis they use a low control, an expected midpoint control, and a high control. To obtain an admission from the government scientist that they would never use just one control

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Stephen Biss

Apr 13, 2018
1 min

Change at One Point but Not at Another Point that is Equivalent

Purpose: To suggest that there is empirical evidence in the matter before the Court of change in response by the approved instrument at the lower end of the measuring interval (reading much lower) and at the upper end of the measuring interval (reading slightly higher) without corresponding change in response at the single data point control test level. To suggest that linearity has therefore changed, and in other words, the calibration curve programmed into the instrument, a

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Stephen Biss

Mar 25, 2018
1 min

Why Does the ATC Say Single Point Control Tests are Good Enough?

Purpose: To explore the differences between a measurement instrument that has a linear relationship between the thing measured and the result v. a measuring instrument that has a calibration curve. To search for an admission that the calibration curve can shift up or down, left or right, or rotate around a point over time. To cross-examine the CFS expert on the lack of empirical study supporting the ATC/CFS hypothesis that a single point control test can always detect drift.

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Stephen Biss

Mar 23, 2018
1 min

Response Drifts Over Time

Purpose: To establish that the hypothesis by the ATC/CFS, that any drift in instrument response (what Hodgson describes as significant drift in accuracy and precision over time) will always be caught by a single point control test, is not supported by any empirical study. To establish that there is no study abstracted in Wigmore on Alcohol that establishes the ATC/CFS hypothesis empirically. To confirm that the new calibration curve created after a re-calibration compared wit

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Stephen Biss

Mar 1, 2018
1 min

8000C Auto-Calibration Sequence - How to Run the Auto-Calibration Sequence

Purpose: To educate the Court about the calibration sequence run on the approved instrument at the factory. To obtain an admission from the Crown expert that without the proper auto-calibration creation of a unique calibration curve, the instrument is not reliable. #autocalibration #calibrationcurve #reliability

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Stephen Biss

Feb 14, 2018
1 min

Traceability of Measurement Result on an Approved Instrument

Purpose: To obtain an admission from the CFS scientist that the traceability of a measurement result on an approved instrument or a truck weigh scale is through the calibration of the instrument at the factory or a proper recent re-calibration by the manufacturer or factory authorized service centre. At the time of calibration a calibration curve is created to establish a relationship between the electrical signal coming off the detector in the AI or the weigh scale and the d

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Stephen Biss

Jan 11, 2018
1 min

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 #ca

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Stephen Biss

Jan 11, 2018
2 min

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

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Maybe the Instrument Is No Longer Linear Enough to Be An "8000C"

BAC Analysis in a Lab Without Bracketing Controls is at Best Qualitative not Quantitative

Change at One Point but Not at Another Point that is Equivalent

Why Does the ATC Say Single Point Control Tests are Good Enough?

Response Drifts Over Time

8000C Auto-Calibration Sequence - How to Run the Auto-Calibration Sequence

Traceability of Measurement Result on an Approved Instrument

Instrumental Deviations from Beer-Lambert Law

Bandwidth of Filters Changes Over Time