The Borkenstein Breathalyzer
Looking back to the beginning of evidentiary alcohol testing
Counterpoint Volume 8: Issue 1 - Article 5 (May 2024)
Jan Semenoff, BA, EMA
Forensic Criminalist
1954 – Dr. Jonas Salk begins polio vaccinations of children. Elvis Presley’s records are first broadcast in Memphis. Sports Illustrated is published for the first time (and future cover model Christie Brinkley is born). Radio is AM. Televisions are black & white, and have tubes. By today’s standards, the electronic technology of the day was in its infancy. Lieutenant Robert Borkenstein patents the Breathalyzer while working for the Indiana State Police as a crime scene photographer and technician. He received his bachelor’s degree 4 years later, while studying under Dr. Rolla Harger. For his life’s work in traffic safety, he is ultimately awarded an honorary Doctorate.
May 2024 marks the 70th anniversary of the original Breathalyzer, patented by Robert Borkenstein on May 10th, 1954. It was one of the first portable devices utilized by law enforcement to measure the breath alcohol content of suspected drunk drivers. Although Dr. Rolla Harger's Drunkometer had been developed a few decades before (with Borkenstein's assistance), it was the Breathalyzer that was first able to precisely quantify the breath sample volume provided, and in turn, create a Breath Alcohol Concentration (BrAC) reading.
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The Breathalyzer was "a photo-electric device capable of collecting a sample of deep lung air, analyzing it for alcohol, and expressing the value as a blood-alcohol concentration". The term Breathalyzer has become the generic term for breath alcohol testing devices. The Breathalyzer was one of the first devices to precisely quantify the amount of exhaled breath delivered into the instrument, beyond Harger's simple "blow into the balloon" breath sample capture.
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Since the popularized empirical measurement instrument for impaired driving was the Borkenstein Breathalyzer, perhaps it would be prudent to examine how that instrument worked. The instrument, with its operational strengths and its weaknesses, founded much of the early case law with regard to breath alcohol testing, and more importantly, established some of the operational requirements for breath alcohol testing still used today. Based on 1954 technology, the Breathalyzer was a breakthrough in its day.
The instrument itself uses simple circuitry, a mechanical piston and gas delivery system to collect the sample of breath, and relies upon the change in colour of a chemical solution when combined with alcohol. This reagent solution is “apple-juice coloured” and is stored in a tiny glass vial composed of the following chemicals:
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The quantitative determination of alcohol concentrations using this potassium dichromate/sulfuric acid mixture as a reagent was used by scientists about ninety years before being used by Borkenstein. Beauchamp first used this technique in 1865 to test for the presence of alcohol in a solution, so Borkenstein’s adoption of this process was hardly “new science.” Ethanol will also react with a solution of potassium permanganate and sulfuric acid to produce a color change. This was the basis of Harger's Drunk-o-Meter of the 1930's and the crystals it contained.
When originally put into the Breathalyzer, the reagent ampoule first had to be checked visually to ensure it contained no visible impurities. It was also checked in a “Go-No Go” gauge to ensure it was the correct diameter, and ensured the correct volume of about 3.0 millilitres of reagent solution was present when the meniscus of the solution just touched the edge of the "Go" side of the gauge. The neck of this ampoule was then cracked off, a bubbler (or pipette) inserted and attached to the sample tube assembly, and the ampoule placed in the right-hand optical tray. It was now referred to as the test ampoule.
The left hand optical tray also contained a reference ampoule, one that has also been checked for impurities and gauged, but with the top left intact. It was imperative that both ampoules came from the same batch and had identical lot numbers. They needed to have identical color signatures for the Breathalyzer to be photo-electrically balanced. Once both ampoules were in place, they were optically balanced using a light meter built into the instrument.
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Between the two ampoules on the optical array was a light bulb. When switched on, it emitted light through both ampoules. On the other side of each of the ampoules was an electronic photocell similar to one found in simple cameras of the 1950's (with blue filters to increase the contrast). The light bulb was “balanced” by use of a thumb wheel connected to a rack and pinion arm system. As the thumbwheel was turned, the light bulb moved left and right between the ampoules, until the amount of light hitting both photocells was identical.
The operator judged this by watching an electric voltmeter on the top of the Breathalyzer. When the needle on the voltmeter (called a null meter) was centered, this indicated that the amount of light striking each photocell was the same. Each photocell was in turn producing an equal voltage. The optical array had been aligned. At this point, the BrAC arm was pulled back off the rack and pinion arm and set to ZERO on the BAC chart.
In order to ensure that no residual alcohol remained in the piston or collection tubes from previous subjects, the Breathalyzer first had to be flushed, or purged, by the operator. This was accomplished by attaching an aspirator bulb to the sample collection tube and flushing room air through the system. This room air was, in essence, also measured to determine if any ambient interferents were present. A reading greater than 10 mg/100mL (0.01 g/dL) would result in a failed purge test. The entire test procedure would then have to be re-started with a fresh test ampoule.
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Following the first purge, the BrAC needle was pulled back to disengage it from the rack and pinion arm again, then carefully positioned on the “START” line on the BAC chart. The Start Line was slightly below the zero point on the BAC chart at approximately the negative (-) 0.005 g/dL position. This was thought necessary to take into account the additive effect any endogenous oral interferent possibly contained on the subject’s breath might introduce. The Breathalyzer was now purged and balanced, and ready to receive the breath sample from the subject.
The subject’s breath sample was captured by having them blow into a mouthpiece connected to a plastic tube. The tube ran into the instrument, and from there, into a small aluminum cylinder, which was wrapped with a heating blanket at 50 +/-3 degrees C to prevent condensation. The total volume of the cylinder was about a fifth of a cup (56.5 mL). As the subject exhaled, a piston was pushed upward inside the cylinder, exposing two small vent holes. Once pushed up to the top of the cylinder, the piston was held in place by some magnets.
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Exhaled breath from the subject continued to flow out the vent holes, and into the internal circuitry compartment of the Breathalyzer. When the subject stopped blowing at any time during provision of a sample, vertical-play in the piston-magnet arrangement made it possible for the piston to fall back down slightly in the cylinder, covering the vent holes, and trapping a known volume of exhaled breath – 56.5 millilitres.
The challenge for the Breathalyzer operator was to capture a true sample of deep lung air. Remember, deep-lung air was the target, because this is where the Blood-to-Breath Ratio of alcohol is thought to be located. With the slight resistance that was offered by the tube and piston, an average person needed to blow for about 10-12 seconds before they visibly began to taper in their exhalation. But, the decision as to when alveolar air was being provided rested entirely with the operators, and their best judgment.
It was at that point that the prudent operator pinched off the donor’s tube to capture the sample (to prevent the subject "sucking-back" some of the exhaled air in the cylinder, thereby lowering the alcohol analyzed in the sample). I’ve seen smaller subjects begin to taper in as little as 6 seconds, and larger more robust subjects blow for almost 20 seconds. The goal was to truly capture a sample of deep lung air - the gold standard at the time.
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Once the breath sample was captured, a knob on the top of the Breathalyzer was turned that disengaged the magnet holding the piston to the top of the cylinder. The knob also pinched off the collection tube from the inside of the instrument, and opened up another tube connected to the test ampoule. Exactly 52.5 millilitres of deep-lung air began to bubble through this reagent vial through a small glass pipette. The rest, 4.0mL, remained in the tube transfer system, and had to be purged out as residual contamination during subsequent stages of analysis.
Once the known-volume breath sample, collected from the subject and stored in the cylinder, began to bubble through the solution in the ampoule, the chemical reaction between the alcohol and the reagent occurred. The darker yellow potassium dichromate solution was converted by the alcohol to form a lighter yellow chromium sulfate solution. The silver nitrate in the solution was simply a catalyst – a substance that made the reaction go faster without participating in the reaction.
The reaction took about 90 seconds to complete. During that time, a timing circuit was activated which prevented the light bulb from being turned on. This inhibited a reading from being obtained from an incomplete chemical reaction. (The rate of the chemical reaction becomes important when interferent substances other than ethanol were introduced into the reagent - the rate of the reaction being the only way for the operator to identify an interferent). After 90 seconds, the chemical reaction was complete, and the light bulb circuitry lock was released. All variables were controlled except the BrAC of the subject.
When the chemical reaction between the ethanol and the ampoule solution was complete, the colour of the solution lightened to more of a “straw” colour. More alcohol in the reaction resulted in more potassium dichromate being reduced to chromium sulfate, and the solution became lighter in color. I’ve seen subjects with BrACs so high that a single sample made the solution almost clear. Any test result greater than 0.210 g / dL required the test ampoule to be changed for a new one, and the optical array to be re-balanced, before a second test was performed. The ampoule was said to contain enough reagent to allow for a BAC reading of about 0.650 g / dL and in common practice, a single ampoule could easily perform two evidentiary tests and an alcohol standard calibration on a single subject.
When the light bulb was again switched on, light passed through both ampoules. Remember, the test ampoule in the right hand array was now lighter in color due to the reaction with alcohol. More light was therefore able to pass through the test ampoule and strike the photocell. More voltage was then produced on this photocell, and the needle on the voltmeter or galvanometer would deflect towards the left. Again, I’ve seen readings so high that when the light was turned on, you could hear the needle “slap” against the side of the voltmeter. The optical array was no longer aligned.
To re-align the optical array, the thumbwheel was again turned, moving the light bulb on the rack and pinion arm towards the left hand reference ampoule with the darker solution. The light bulb, now being closer to the ampoule with the darker colored solution, gives a greater intensity of light on that side of the array. The operator simply moved the light bulb towards the darker reference ampoule until the light striking both photocells was the same, as indicated by a balanced voltmeter. The optical array was now re-balanced.
This, by the way, demonstrates Beer's Law at work. More light passed through the lighter colored ampule. In terms of Beer's Law, more absorbance of the light occurred in the darker colored ampule. This absorbance difference was quantified and measured by the light meter in the optical array.
Moving the rack and pinion arm holding the light bulb had the further effect of causing the BrAC needle to pivot. The pivoting BrAC arm moved in direct proportion to the movement of the light bulb on the rack and pinion arm. The greater the amount of alcohol in the subject’s breath, the lighter the test ampoule became. The lighter the test ampoule, the closer the light bulb had to move towards the darker reference ampoule to photo-electrically re-balance the optical system.
More light bulb movement on the rack and pinion arm moved the BAC needle a greater distance. Once the voltmeter again indicated a re-balanced optical system, the movement of the BrAC needle indicated on a scale the blood alcohol content of the subject.
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The operator was required to verify the operation of the Breathalyzer against a known alcohol standard one time during the testing sequence, and using at least one test ampoule. The Standard Alcohol Solution, or SAS, was placed in a baby bottle arrangement called an Equilibrator that had an aspirator bulb to pump room air through an aerator, generating sufficient force to lift the piston to the top of the cylinder to capture a test sample. The temperature of the room and the temperature of the SAS had to be identical. Temperatures were recorded to 0.1 degree C.
It should be noted that the increments on the scale were very small. It was sometimes hard to tell if the reading was 0.081 g / dL or still touching the 0.080 g mark. This is one of the reasons that various jurisdictions adopted the notion of truncated readings. Readings between 0.081 g to 0.089 g / dL were ALL rounded down to 0.08 g.
In this way, operator inaccuracy and judgment of the reading were minimized, and the accused was given the appropriate "benefit of a doubt". In order to be charged with having a BAC in excess of 0.080 g / dL, the subject would have to provide a sample that was analyzed at 0.090 g / dL or greater.
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The Advantages & Disadvantages of the Breathalyzer
Advantages
Even though it was 1950's technology, the Breathalyzer still has some advantages over newer computerized devices:
- Operating it was very much a hands-on situation. An experienced operator could tell if the device was working correctly by the response and feel of the moving parts. It was not the "black box" experience of today. The operator had to be competent in its use, and as such, the operators tended to be better trained than operators today, many of whom know little more than "pushing the start button"...
- The compliance of the subject exhaling properly was also easily discernible. A smaller statured person could still provide a sample where the newer instruments have a requirement for flow force and volume that may not otherwise be achieved. The operator could hear the "slap" of the piston as it hit the top of the cylinder, indicating the test subject was blowing hard enough, and hear the air escaping out the cylinder vent holes.
- If any of the individual components malfunctioned, either a reading was not obtained (as in a dead lightbulb), or the reading was lowered due to leakage in the internal tubing.
- An experienced operator could identify non-specificity towards ethanol by the response of the test ampoule. The optical array would not balance during subsequent tests, or give inordinate numerical results. Identifying specificity towards ethanol was a component of operator training that somehow disappeared when the new electronic units used a programmed algorithm to determine the presence of interferent chemicals.
- The quickest a second breath sample could be obtained with a Calibration Check in between the samples was about 12 minutes (the blank and purge cycles were long and complicated). Therefore, the dissipation of any fresh mouth alcohol from oral contamination would be identified with the longer wait time. Newer instruments use a 2-3 minute wait period between samples, and this is simply not enough time for oral contamination to dissipate.
Disadvantages
Of course, there were severe drawbacks with the Breathalyzer that newer technologies ultimately improved:
- The Breathalyzer was extremely complicated to operate, with over 100 steps on a check sheet that had to be correctly performed, in the specific order required, to obtain two breath samples with a calibration check. Newer technologies are simple "push-to-start" devices. This is a dual-edged sword comparing Advantage #1 above.
- The disposable ampoules were expensive, and contained a highly concentrated acidic solution. More than a few operators received severe acid burns on their hands, uniform shirts, etc. Disposing of the broken glass acid ampoules was also a biohazard issue.
- It took about 2 weeks to train an operator in the complicated device and its procedures. Today's operators are often trained in as little as 6-8 hours, but again, this is a dual-edged sword, as the newer operators don't often really understand how a suitable breath test sequence should be performed.
- There was no independent analysis of the test protocol for an individual test subject. The operator could easily declare a person had whatever BrAC they wanted, hence the oft-used term "Dial-a-drunk". Pretty much every sequence of testing was discretionary on the part of the operator, with their own individual integrity serving as their guide.
- The Breathalyzer needed routine servicing and maintenance to keep it running. Pistons and hoses would get gunked up from dried saliva, etc. Light bulbs would burn out. Hoses would leak. Routine maintenance had to be a part of initial operator training, adding to the time and expense.
- There was absolutely no way to determine contamination by a burp, or other form of fresh mouth alcohol. Consequently, a close and continuous observation period of at least 15-minutes prior to and between samples was mandatory.
- The reagent ampoules reacted with acetone, ethanol, isopropanol, methanol, etc. But again, an experienced operator could tell if this was a problem.
- The maximum reading obtained by the dial was 0.400 g/dL. Operators were taught that with very high readings, they would dial the unit to 0.400, reset the pointer at 0.00, and keep balancing the optical array. My highest reading I ever received was 0.420 g/dL. I did the test three times to make sure I hadn't made a mistake. All were the same 0.420 g/dL. We took the test subject off to the emergency department for treatment for alcohol poisoning. His hospital blood draw came back at .470 g/dL. (with the whole blood conversion, this is about right).
- Temperature control was crucial to within 1 degree Celsius, so using the devices in a trailer at roadside during New Year's enforcement campaigns was virtually impossible.
Regardless of the limitations of the instrument, I'm thankful I had the opportunity to use the Breathalyzer early in my career. I believe it made me a better Qualified Technician. Apart from the historical significance of the device, keep in mind that it set the tone for breath testing, and many of the procedures we follow today were handed down, by necessity, due to the limitations of the technology. And, as newer devices were introduced, they were compared to the "tried and true" Breathalyzer, so many of the features and procedures of that device were ultimately part of what came after, and what still occurs today.
NOTE: The term “Breathalyzer” is a trademark presently used by the Draeger Corporation. All references in this guide to the “Breathalyzer” refer entirely to the original Breathalyzer models and are NOT in any way to be construed as representative of any instruments currently manufactured by the Draeger Corporation. The early manufacturer of the Breathalyzer was the Stephenson Corporation, and was therefore known as the Stephenson Breathalyzer. Stephenson sold the rights for the Breathalyzer instrument to Smith & Wesson Corporation who later sold it to the National Draeger Corporation, who owns the patent and trademark at present. All instruments produced by these companies refer to the Borkenstein Breathalyzer.
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