Gas Chromatographic Determination of Dopamine at the Nanogram Level

Clarke, Donald D.; Wilk, Sherwin; Gitlow, Stanley E.; Franklin, Morton J.

doi:10.1093/chromsci/5.6.307

Cited by 39 publications

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“…The two sets of results were always within * 5% of each other. Clarke et al (1967) have reported a gas chromatographic method for determining dopamine and related catecholamines as trifluoroacetyl (TFA) derivatives. We have investigated their technique for determining tyramine in foods and found it to be extremely sensitive.…”

Section: Paper Chromatographymentioning

confidence: 99%

“…The extraction procedure of tyramine in foods and subsequent steps of trifluoroacetylation were most suitable for our purpose. As the TFA derivatives are easily hydrolyzed in the presence of water or traces of acids or base (Clarke et al, 1967), rigid anhydrous conditions must be maintained throughout the procedure. The TFA derivatives are not stable for a long time and they should be analyzed on the same day they are prepared.…”

Section: Paper Chromatographymentioning

confidence: 99%

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Analysis and Significance of Tyramine in Foods

Sen¹

1969

Journal of Food Science

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SUMMARY— The tyramine levels in different varieties of cheeses, alcoholic drinks, and other foods were determined. Many of the food samples, analyzed by an existing fluorometric method, contained large amounts (up to 2.2 mg/g) of tyramine. Synephrine and octopamine, although rarely present in food, interfered with the fluorometric analysis. A gas chromatographic method was developed in which tyramine was extracted from foods and then analyzed as its trifluoroacetyl derivative using an electron capture detector. The gas chromatographic method was more sensitive and specific than the fluorometric method, and it permitted detection of 0.1–0.2 nanogram tyramine even in the presence of synephrine and octopamine.

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Section: Paper Chromatographymentioning

confidence: 99%

Section: Paper Chromatographymentioning

confidence: 99%

Analysis and Significance of Tyramine in Foods

Sen¹

1969

Journal of Food Science

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“…A saturated benzene solution of the liquid Al-isopropoxide shows the major CH3-doublet and three minor doublets. In the CH-proton region, 14 peaks can be detected. The important difference between the liquid and solid Al-isopropoxides is a change in the degree of polymerization (from 3 to 4) and this change is reflected somewhat in the lower field chemical shifts.…”

Section: Discussion and Resultsmentioning

confidence: 99%

Characterization of gas chromatography of alkoxides of aluminum and of some Group IV elements

Brown¹,

Mazdiyasni²

1969

Anal. Chem.

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increases in Zu values for phenol and propionic acid. However, it has been shown previously (15) that column oxidation of asphalts results in a decrease of free OH absorbance while hydrogen-bonded OH absorbance increases significantly. Much of this hydrogen bonding remains intact even in dilute solutions so that the net result is a loss of free OH absorbance even though the total OH in the sample has increased. Upon silylation a general decrease is noted in the hydrogen-bonded absorbance; however, no quantitative determination could be made of the hydrogen-bonded region (about 3500-2500 cm-l) because it is overlapped by the C-H stretching region.Repeatability of the Si1 ylation Technique. Two separate packings were prepared, using asphalt D as the substrate. Two columns of each packing were processed in the manner described in the Experimental section. The data, included in Table I, show a maximum variation in specitic interaction coefficients for a given test compound on duplicate asphalt samples of three I, units. This is within the normal variation on duplicate runs of the same sample. The preliminary indication is that the technique gives reproducible results. SUMMARY AND CONCLUSIONSSilylation of an asphalt within an IGLC column offers a convenient means to study asphalt functionality. More specifically, the reagent, BSA, reacts with most of the phenolic and carboxylic acid hydroxyl groups present in either asreceived or column-oxidized asphalts. Comparison of infrared spectra before and after silylation substantiates this conclusion.Silylation reduces the phenol and propionic acid Zu values on both oxidized and unoxidized asphalts to a common value characteristic for each individual test compound. This results from the blocking of the carboxylic acid and phenolic OH groups in the asphalts. These groups are believed to be the ones by which phenol and propionic acid differentiate among asphalts. The functional groups which interact strongly with formamide remain after silylation. These groups appear to be carbonyl functions.The silylation technique should be applicable to investigations of the chemical structure of macromolecules and nonvolatile materials.ACKNOWLEDGMENT AI-tris-isopropoxide, tetrakis-isopropoxides of Ti, Zr, Hf, Si and Ge, and tetrakis-tertiary amyloxides of Ti, Zr and Hf have been synthesized as precursor materials for the preparation of single and mixed phase refractory oxides. An attempt has been made to characterize these compounds on the basis of chemical analysis, infrared spectra, proton NMR, mass spectrometry, thermogravimetric analysis, and gas chromatography. The IR spectra (4000-270 cm-1) of the tetrakis-tertiary amyloxides of Ti, Zr, and Hf have been obtained for the first time. In the CsBr region a number of very strong absorption bands are found that are characteristic absorption frequencies for the tertiary amyl compounds. These compounds are liquid (with the exception of the AI compound which is solid), of considerable volatility, and thermally stable at relatively high tempera...

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“…The determination of amines (Clarke et al, 1967;Dove, 1967;McCurdy and Reiser, 1966) and amino acids (Gee, 1967;Gehrke and Stalling, 1967;Lamkin and Gehrke, 1965) by gas chromatography after converting them to trifluoroacetyl derivatives is well documented. This paper adds the carbamic acid esters to the list of compounds forming electron-capturing derivatives with trifluoroacetic anhydride.…”

Section: Carbamatementioning

confidence: 99%