Since the utilization of the ThinPrep Pap Test in clinical practice, laboratories have strived to optimize cellular yields from cervicovaginal samples. Bloody specimens that often hamper cytologic interpretation and/or render a specimen unsatisfactory for diagnosis on conventional smears also affect
The identification of N-acetylglycine as a contaminant of glacial acetic acid
โ Scribed by Linda M.St. Onge; Susan L. Kittle; B.Hamilton Paul
- Publisher
- Elsevier Science
- Year
- 1976
- Tongue
- English
- Weight
- 419 KB
- Volume
- 71
- Category
- Article
- ISSN
- 0003-2697
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โฆ Synopsis
This paper provides evidence by gas chromatography-mass spectrometry (GC-MS) that N-acetylglycine is present, in varying amounts, as a contaminant of all samples of analytical grade glacial acetic acid that have been examined in our laboratory. Supportive evidence for the GC-MS data was obtained by amino acid analyses of evaporated samples of acetic acid which were subjected to acid hydrolysis and then analyzed by ion-exchange chromatography.
Although the identification of N-acetylglycine has been established with certainty, small quantities of other amino acid derivatives which have not yet been identified are also present in glacial acetic acid. These additional amino acids have been identified after acid hydrolysis. It should be pointed out that although amino acids are of chief interest here, they comprise approximately 1% or less of the total organic contamination.
A very marked reduction of the concentration of N-acetylglycine and all other contaminants was accomplished by slow distillation of the glacial acetic acid through a column of packed Raschig rings.
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The rate constants were determined for the nitrosation reactions of the following substrates: Methyl (MU), Ethyl (EU),Propyl (PU)Butyl (BU), and Allylurea (AU). The rate equation found at a constant pH was: [Urea]. The reactions were carried out in pre-v ฯญ k[HNO ] 2 dominantly organic media(dioxane