In the next test foundation, a test from the well-cooked corpse from a supposed arson fire to a suburban make up is existing to the witness. The witness explains the GCMS analyze results. The investigative attorney has before now recognized chain of safekeeping and the exact theorys validity.
Commentary: This is a test foundation.
The next is a work of fiction, not allied at each and every one to whichever definite case, elapsed, or present.
This material is only provided as an case in point to illustrate demonstrate techniques.
Q. What is your occupation?
A. I am an analytical chemist at the California Area of Justice.
Q. What is an analytical chemist?
A. I question samples to determine their concerto with exact techniques and instruments.
Q. Thrill divulge the jury almost the types of samples that you question in your work.
A. Numerous of the specimens that we process are supposed of containing narcotics. I dedicate yourself to in identifying specimens from supposed arson fires and explosives. One case in point, perhaps an researcher gathers a test from a burnt make fun of in a make up fire. We make something stand out the filling of the specimen. Customarily, the detectives be after to discern if an accelerant was worn to fuel the fire and if so, what accelerant was worn. From moment in time to moment in time I what's more question body fluids and tissues for drugs and their metabolized miscellany.
Q. Thrill divulge the jury almost your official teaching.
A. I have a Bachelors and Master of Knowledge mark in Chemistry from M.I.T, and a PhD. in Analytical Chemistry from U.C. Berkeley.
Q. May possibly you divulge the jury almost the courses you took at U.C. Berkeley?
A. Yes, I took numerous courses in analytical chemistry. I took two semesters of broad-spectrum analytical chemistry. Then present was a survey course on analytical instruments, which incorporated a laboratory component where we operated all apparatus that our course sheltered. Present was a round table class on analytical instrument troubleshooting techniques where we well-read how to make something stand out instrument malfunctions and how to prevent counterfeit positives and counterfeit negatives.
Q. Did whichever of these courses cover the GCMS instrument?
A. Yes, each and every one of them. The professor for the round table course, Professor G. See is renowned as one of the chief experts in the incident of the make use of of the GCMS instrument in hydrocarbon testing.
Q. How prolonged have you been an analytical chemist?
A. For almost ten years, each and every one of that moment in time with the California Area of Justice.
Q. Have you published whatever thing in the analytical chemistry pasture?
A. Yes, furthermore my theses I have on paper twenty articles on analytical chemistry, including a reserve on the GCMS
testing.
Q. What is GCMS?
A. That stands for chatter chromatography and mass spectrometry. It is a two-stage process. The chatter chromatography apparatus separates the test addicted to the different chemicals present by vaporizing the test. After that the mass spectrometry device identifies the different chemicals by measuring the mass of every element.
Q. How numerous of the articles that you published deal with GCMS?
A. Almost partially or my articles were on GCMS, with the instrument for arson investigation, drug identification, and bomb blasting powder description.
Q. Is GCMS hard reliable?
A. Yes, the GC is a superior separation tool and the MS provides specific results. When the GC is united with the MS, you have an enormously effectual analytical tool.
Q. What do you median by specific results?
A. A specific product is when a analyze shows that only one mark of gasoline was worn, with trivial likelihood of a counterfeit optimistic product. A nonspecific product is when a analyze produces a product indicated by extra than one mark of gasoline. The nonspecific product gives numerous counterfeit optimistic results.
Q. What is a counterfeit optimistic product?
A. A counterfeit optimistic is when the analyze says one mark of gasoline was worn when in fact another mark was worn.
Q. Is GCMS a specific analyze or a nonspecific analyze?
A. Specific. The GC by itself is not specific, excluding with the MS apparatus with the GC gives a specific product.
Q. Are you familiar with whichever look into that mentions that with MS with G.C. gives a specific product?
A. Yes, that was sheltered in my instrument lab class at Berkeley. The pioneering look into was performed by Professor Ann L. Itical at Wisconsin. I decipher all that Professor Itical wrote on the GCMS order.
Q. Is the GCMS order usually customary in the exact commune as a way to make something stand out the mark of gasoline worn in an arson fire?
A. Yes, it is the favorite analyze.
At this detail, counsel seeks to have the witness express the GC process with a visual benefits. The counsel follows decorous courtroom procedure by performance the chart to the opposing counsel and marking the chart as exhibit 3.
Q. Your Principle, might the witness step through and speak to the exhibit?
J. Yes, the witness might step through and speak to the item clear exhibit 3 for identification.
Q. Thank you, your Principle. Looking at what is clear as exhibit 3 for identification, what is this?
A. This is a picture of the tools worn in chatter chromatography.
Q. What gears does the GC involve?
The witness points to every component bit answering the examine.
A. The GC has the jab port, the carrier chatter, the paragraph, the test splitter, the detector and the productivity recorder.
Q. A small sum of the test is dissolved. Then this solution is injected addicted to the jab port, at this juncture, with a squeeze. The jab port is piquant so the test vaporizes addicted to a chatter. The carrier chatter pushes the test, this way, all the way through the paragraph. Every element in the test firewood to parts of the paragraph in different conduct a quantity of chemicals jab to the paragraph and do not get here back off easily, bit a quantity of chemicals do not jab at each and every one. A good number chemicals be in wherever in relating. The superior the element firewood, the longer it takes for that element to tour all the way through the paragraph. When every element eventually leaves the paragraph, the detector, at this end, trial it and the test splitter sends piece of the element to the mass spectrometer.
Bit the witness corpse near exhibit 3, the counsel suitably has another visual benefits clear exhibit 4 for identification. The counsel displays exhibit 4 in face of the witness.
Q. Thank you, your Principle. Looking at what is clear as exhibit 4 for identification, what is this?
A. This is a picture of the tools worn in mass spectrometry.
Q. What gears does the mass spectrometer involve?
A. The witness points to every component in the picture bit answering. The MS has an ionization chamber, an analyzer tube, an electromagnet, a detector, and an productivity recorder.
Q. How does the MS apparatus work?
A. The splitter spurt from the GC enters the MSs ionization chamber, in at this juncture, where every element receives an electrical charge. This electrical charge causes the molecules in the element to destroy separately addicted to thrilling fragments. The thrilling fragments tour all the way through the analyzer tube towards the electromagnet. Depending on the mass of the fragments, every fragment is precious another way by the electromagnet. When the fragments come to the detector, at this end, they get away from their charge and the productivity recorder produces a mass spectrum for every component.
Bit the witness corpse near exhibit 4, the counsel suitably has another visual benefits clear exhibit 5 for identification. The counsel displays exhibit 5 in face of the witness.
Q. Now looking at what is clear as exhibit 5 for identification, what is this?
A. This is a mass spectrum graph.
Q. What is a mass spectrum?
A. A mass spectrum is a graph of a samples different fragments. Every pattern of fragments is single to that substance. These peaks represent fragments with their respective molecular weights. If the technician suitably analyzes the spectrum, the technician container make something stand out the substance specifically.
Q. Your principle, might the witness homecoming to the witness box?
J. Yes, the witness might homecoming to the witness box.
Questioning resumes next the witness is seated.
Q. How does a technician question a mass spectrum?
A. Suggestion books or laptop archive exist with test spectrums. The technician container associate these test spectrums with the spectrum in examine. Another way to question the spectrum is for the technician to run a secede analyze on a renowned test of what the technician believes the substance to be. If the spectrums match, then the technician has strong-minded the samples self.
Q. Have you had whichever training with the GCMS?
A. Yes, I completed the California Area of Justice drug identification course and another arson accelerant identification course.
Q. Who qualified these courses?
A. The drug identification course was qualified by Dr. Mary Wana, the manager of the California State Drug Identification Institute. The arson course was qualified by Johnny Burst into flames, be first of the FBI arson accelerant identification and description laboratory. This course what's more had an explosives identification course qualified by Guy Fawkes, Scotland Yards chief forensic lab leader. These courses concentrated on with GCMS.
Q. How prolonged were these courses?
A. They were both five-day courses.
Q. How prolonged before did you convey these courses?
A. I took the drug identification course in 1990 and the arson course in 1995.
Q. What arson accelerant identification techniques were qualified at the 1995 course?
A. The widely worn ones, including GCMS.
Q. How did you find out these techniques in the course?
A. The instructors explained the techniques, demonstrated how to make use of them, then we had to make use of them ourselves. It was a hands-on course. We what's more had to find out how to maintain the instruments.
Q. How did the instructors determine if you were talented with the GCMS?
A. We were tested with 20 test compounds. The test vials only had code figures only the instructors knew what was in every vial. We had to make something stand out each and every one the samples exactly to adopt the course.
Q. How numerous times have you worn the GCMS?
A. Maybe almost a thousand times.
Q. And for what time taken of moment in time has this been?
A. Seeing as I took that drug identification course in 1990, so almost ten years.
Q. Have you forever identified a specific accelerant worn in an arson fire?
A. Yes.
Q. Which accelerants have you identified?
A. Kerosene, fuel oil, char-grill lighter fluid, butane, propane, and gasoline. For gasolines, I what's more have identified what specific mark of gasoline was worn.
At this moment in time, the supporter establishes the chain of safekeeping of the specimen. The supporter has approached the witness with the specimen clear as exhibit 6 for identification.
Q. This is what is clear as States exhibit number six for identification. Do you see it?
A. Yes, it is the specimen I tested from the fire at 1234 Fluegel Boulevard.
Q. How do you see it?
A. By my initials and the case number day on this tag.
Q. Next you traditional this exhibit what did you do?
A. I in progress to put in order the GCMS for testing.
Q. What type of GCMS do you have in your laboratory?
A. Our laboratory has a Perkins Deluxe model, which is regularly worn in a good number forensic laboratories in the Us.
Q. In what condition was the GCMS in?
A. The GCMS was in good working condition.
Q. How do you discern that the GCMS was in good working condition?
A. Other chemists make use of the even GCMS. Sooner than every chemist uses the GCMS, the chemist obligation execute a cycle of defensive maintenance checks and maintenance services on the GCMS. Our GCMS had been worn more than a few times sooner than I analyzed this specimen on the that extremely calendar day.
Q. And what calendar day was that?
A. April 31, 1998.
Q. Did you detect whichever deficiencies in the GCMS apparatus?
A. No.
Q. What did you do then?
A. I dissolved a small portion of the specimen in the heavens and injected addicted to the jab port of the GC.
Q. Did you do whatever thing moreover sooner than you analyzed this test?
Q. On this ground how did you execute the analyze?
A. In the even way that I explained sooner than. I compared the spectrum to a published spectrum chart.
Q. What are overlapping peaks?
A. Overlapping peaks median that different chemicals in the specimen did not adequately secede in the GC process. This would give somebody the job of the results unreliable.
Q. Were present whichever overlapping peaks in the testing of States exhibit number six for identification?
A. No.
Q. What is a top cluster?
A. A top cluster occurs when chemicals have the even atomic number excluding different masses. This would give somebody the job of the parent top difficult to determine, making the results unreliable.
Q. Did you see whichever top clusters in the testing of States exhibit number six for identification?
A. No.
Q. Did you run whichever other samples sooner than analyzing this test?
A. Yes, I processed a norm test of Chevron gasoline with Techroline fuel jab protectant sooner than analyzing the specimen in exhibit number six.
Q. Did you do whatever thing moreover to ensure the correctness of the instruments results?
A. Yes, I ran the GCMS instrument over again with another norm test of Chevron gasoline with Techroline fuel jab protectant. I compared the mass spectrum of the two norm samples with the mass spectrum of the specimen from exhibit 6. I experiential that the three spectra were near matching.
Q. What substance did you determine States exhibit number six for identification to be?
A. The substance in States exhibit number six is categorically Chevron gasoline with Techroline fuel jab protectant.
Counsel moves to enter the three mass spectra addicted to demonstrate. The attract instructions them to be entered addicted to demonstrate not including hostility from opposing counsel.
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