An Environmentally Significant Experiment Using GC/MS and GC Retention Indices in an Undergraduate Analytical Laboratory

Guisto-Norkus, Rebecca; Gounili, Giv; Wisniecki, Peter; Hubball, J.; Smith, S. Ruven; Stuart, James D.

doi:10.1021/ed073p1176

Cited by 10 publications

(7 citation statements)

References 2 publications

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“…Plastics and the additives they contain are ubiquitous in our environment, including our food (Bradbury, 1996;Lau and Wong, 1996;Ruuska et al, 1987), our water (Furtmann, 1994;Group, 1986;Guisto-Norkus et al, 1996;Hites, 1973), and our air (Stein et al, 1987;Thuren and Larsson, 1990;Viden et al, 1997). Occupational exposure to these compounds may be substantially higher for some individuals, and is already suspected to be harmful or initiate asthmatic responses in sensitive individuals.…”

Section: Resultsmentioning

confidence: 99%

Plasticizers, antioxidants, and other contaminants found in air delivered by PVC tubing used in respiratory therapy

Hill

Shaw

2003

Biomedical Chromatography

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Of the many compounds that leach from respiratory therapy tubing into air passing through it, we selected five compounds to analyze. The five compounds are known to be potentially carcinogenic, toxic or known to induce estrogenic activity. Parts-per-million and parts-per-billion concentrations of these species were found in the air passing through the tubing: the plasticizers di-(2-ethylhexyl) phthalate (DEHP) and di-ethyl phthalate (DEP), the antioxidants butylated hydroxy toluene (BHT) and p-nonylphenol (p-NP), and the contaminant (from commercial preparation of DEHP) 2-ethylhexanol (2-EH). These levels are high enough to cause some concern about exposure for patients who use oxygen on a long-term basis, those sensitive or allergic to these species, or those with asthma. A method was developed for analysis of solid tubing samples, showing great variability in concentrations of small, volatile molecules from sample to sample. A method was also developed for pre-concentration of small molecules onto Tenax adsorbants from air passing through the tubing. Both solid samples and adsorbant loaded with analyte were analyzed by direct dynamic thermal desorption gas chromatography mass spectrometry (GCMS). This study does not imply that adverse reactions by patients to chemical compounds leaching from respiratory medical tubing will occur but that further investigation is warranted.

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Section: Resultsmentioning

confidence: 99%

Plasticizers, antioxidants, and other contaminants found in air delivered by PVC tubing used in respiratory therapy

Hill

Shaw

2003

Biomedical Chromatography

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“…Learning objectives for this experiment include sample injection techniques, quantification of xylitol using GC–MS, and a comparison of external versus internal standard techniques while allowing students to explore a topic that has direct impact on animal safety. Previous undergraduate laboratory experiments have been developed which utilize GC–MS to analyze and quantify components of diverse samples including gasoline, plasticizers, food, water, urine, perfume, beverages, and others. − GC–MS experiments have also been utilized within the organic chemistry curriculum, since it provides a great opportunity for students to analyze organic reactions such as nucleophilic substitution and elimination reactions . This experiment is designed for upper-level undergraduate students enrolled in organic or instrumental analysis courses.…”

Section: Introductionmentioning

confidence: 99%

Determination of Xylitol in Sugar-Free Gum by GC–MS with Direct Aqueous Injection: A Laboratory Experiment for Chemistry Students

et al. 2018

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Proficiency with instrumental analysis via GC–MS is an important skill for chemistry students. The application of analytical techniques and fundamental theoretical principles to real-world problems can be valuable learning exercises for undergraduates which can also improve their analytical thinking skills. Xylitol is generally considered safe for human consumption and is frequently used in sugar-free gum; however, it is extremely toxic to dogs. In this laboratory experiment, upper-level undergraduate chemistry students extract xylitol from both fresh and chewed gum sticks followed by direct aqueous injection GC–MS analysis. Students learn the proper steps and techniques required for sample extraction and preparation and GC–MS analysis, and they determine concentrations of xylitol present in gum samples. Identification and quantification of the chemical components in gum extract occurs via GC–MS analysis; however, other GC detectors could be used. Students also compare external and internal standard calibration methods for xylitol quantification. Upon quantification of xylitol in chewed and unchewed gum samples, students are able to calculate the level of hazard for dogs upon ingestion.

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“…In recent GC-MS experiments reported in this Journal (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16) only EI was used for ionizing the separated compounds. This high-energy process of EI often results in fragmented species, which makes compound identification difficult owing to the absence of the molecular ion.…”

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confidence: 99%

Identification of Glue Vapors Using Electron Impact and Chemical Ionization Modes in GC–MS

2006

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The analysis of the vapors from six commercial glues provided an interesting and challenging lab assignment for students in an instrumental analysis laboratory course. Students used both electron impact (EI) and chemical ionization (CI) modes of operation in GC–MS to identify the volatile components in their assigned glue. Chemical ionization using methane as the reagent gas provided a complementary analysis to the more common EI mode of operation. In the softer CI mode, there is a higher probability of observing the molecular ion. Students were required to explain the observation of specific mass fragments observed from both EI and CI operations in terms of their reactions in the ion source of the mass spectrometer. This interpretation of mass spectra provided the students an educational exercise for understanding the ionization processes that occur in mass spectroscopy.

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An Environmentally Significant Experiment Using GC/MS and GC Retention Indices in an Undergraduate Analytical Laboratory

Cited by 10 publications

References 2 publications

Plasticizers, antioxidants, and other contaminants found in air delivered by PVC tubing used in respiratory therapy

Plasticizers, antioxidants, and other contaminants found in air delivered by PVC tubing used in respiratory therapy

Determination of Xylitol in Sugar-Free Gum by GC–MS with Direct Aqueous Injection: A Laboratory Experiment for Chemistry Students

Identification of Glue Vapors Using Electron Impact and Chemical Ionization Modes in GC–MS

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