Limitation Of Gas Chromatography

Marwah Alabbad Post lab 10/21/15 Question 1: 1. Experiment 1: Number of trails NaOH concentration (M) Volume of HCl solution (mL) Initial volume of NaOH(mL) final volume of NaOH(mL) The volume of NaOH to titrate HCl (mL) Concentration of HCl (M) 1st 0.1023 25.0 10.05 36.12 26.07 0.085 2nd 0.1023 25.0 5.74 31.40 25.66 0.105 3rd 0.1023 25.0 9.84 35.52 25.68 0.105 First trail calculation: 0.02607L× (0.1023mole NaOH/1L)×(1 mol of HCL/1 mol of NaOH)×(1/0.025)= 0.085M of HCl

The mobile phase used was a mixture of ammonium acetate buffer and acetonitrile at a ratio of 400:600. A flow rate of 1 mL/min was maintained, and the detection wavelength was 292 nm (22). The required studies were carried out to estimate the precision and accuracy of the HPLC method and were found to be within limits [percent coefficient of variation was less than 15%]. Sample preparation briefly involved 0.4 μ membrane filter through which the sample was filtered, diluted with mobile phase, and 10 μL was spiked into

Statement of the Problem DNA has become a vital part of criminal investigations. DNA can include and exclude suspects of criminal investigations. During a criminal investigation, all DNA should be collected, properly preserved and tested, but at times this does not occur or the technology was not available for this process to occur. In addition, DNA has become an imperative portion of exoneration cases.

It has become a powerful tool in the criminal justice system, it provides conclusive evidence that can link a suspect to a crime, help free individuals who have been wrongfully convicted of crimes, and identify victims of crimes who are deceased. DNA evidence is analyzed through a PCR (polymerase chain reaction) this method allows for the smallest specks of any type of DNA. (Staff) In the criminal justice system, there are many ways that DNA evidence is used in we use it to Identify suspects, DNA evidence collected from a crime scene is sent off and compared to DNA samples collected from suspects or from a DNA database. To determine if a suspect's DNA matches the DNA found at the crime scene.

Molecular analysis is a well-known method and recently used by researchers. Using this

Any DNA that remains in CODIS available for comparison against new samples from recently apprehended criminals and old samples from unsolved cases. This has become an invaluable tool for law

Auditory brainstem responses to complex sounds (cABRs) • Stimuli in the literature: • Vowels (both synthetic & natural) • CV syllables (synthetic, natural, & hybrid) • Words (ex: car, rose, chair) • Phrases (ex: chicken pot pie) • Environmental sounds • Non-speech vocal sounds (ex: a baby’s cry • Musical sounds and melodies Clinical Applications: The cABR is replicable across test sessions and reliably measured under passive conditions using a small number of electrodes. • Identify individuals likely to benefit from auditory training. • Assessment and documentation of treatment outcomes.

DNA in Forensic Science DNA is the carrier of genetic information in humans and other living organisms. It has become a very useful tool in forensic science since it was discovered. In forensic science, DNA testing is used to compare the genetic structure of two individuals to establish whether there is a genetic relationship between them. One example of the use of DNA in forensic science that is important in biology today is comparing a suspect’s DNA profile to DNA that was discovered at a crime scene.

Chemistry – As being a crime scene investigator one must have the knowledge and skills of chemistry at the scene of crime as knowledge of the chemical composition, structure, and properties of substances and of the various chemical process which do occur and later which transformation that they may undergo. This includes uses of chemicals and their interactions, certains signs which can be considered dangerous, their techniques of being produced, and the way of being disposed; it’s one of the outmost important skills a crime scene investigator must pose at the scene of

It has been said to have revolutionized forensic investigations. Deoxyribonucleic acid profiling has been used to exonerate the wrongly accused, convict the correct criminal, and even do something as little as finding out who the father of a child is (Roewer, Lutz). Deoxyribonucleic acid today can be obtained from processing bodily materials such as spit, semen, or blood. Because of the fact that all cells in the human body contain a nucleus and nuclei contain DNA, virtually any evidence left behind that is a bodily fluid can be tested for Deoxyribonucleic acid to help tie or eliminate those from a crime

DETERMINATION OF PERCENTAGE ETHANOL IN BEVERAGES 1. Introduction to Gas Chromatography Gas chromatography is a very powerful separation technique for compounds that are reasonably volatile. The components of a sample partitions into two phases, the 1st of these phases is a immobile bed with a great surface area, and the other is a gas phase that permeates through the immobile bed. The sample is evaporated and passed by the mobile gas phase or the carrier gas through the column. Samples separates into the stationary liquid phase, based on their solubilities at the given temperature.

For example, if a baby is born with a sex-linked disorder such as Turner's syndrome, after making a diagnosis, the doctor can consult the parents about gene therapy. If approved, the doctor can take a sample of the baby's DNA and perform a southern blotting method in order to pinpoint the exact segment of DNA which is disordered (in this case, the problem is due to a lack of a second X chromosome). Amazingly, southern blotting can also be used in crime solving! Forensic anthropologists sometimes use the southern blotting method on the fingerprints found at a crime scene in order to identify whom it belongs to. It is not commonly known how exactly forensics is used in DNA identification, and this is one of the methods used.

DNA analysis is also now regularly conducted and may lead to a single source profile or a mixture. The latter may not be as desirable as the former as the probative value of the profile is very less. Similarly there are sophisticated technologies for analyzing other biological evidence such as blood, semen, bone/tissue, saliva urine, hair and fingernails. Automated ballistics technology too has become mainstream and cases that were earlier thought to be unsolvable can now to be solved.

ABSTRACT Purpose: Halitosis is defined as an unpleasant odor that emanates from the oral cavity with intra–oral and/or extra–oral origins. The present study assessed factors influenced halitosis using different diagnostic modalities.

This is when forensic scientists get to work! This work varies tremendously between different types of evidence. Mass spectrometry and/or gas chromatography may be preformed chemical evidence, such as liquids, residues, drugs, bodily fluids, and other unknown substances, to determine what the sample is made of. Samples possibly containing DNA may need to be sent to an outside lab for DNA testing. With the advanced DNA understanding and technology that we now have, scientists only need 18 cells to preform a successful test!