Techniques for Collecting Volatile Components from Haddock Flesh for Gas Chromatographic Analysis

Abstract

SUMMARYThe volatile compounds isolated from haddock (Melanogrammus aeglefinus) flesh were analyzed by cryogenic gas chromatography. Four methods of collecting the volatile compounds were studied and evaluated. Chromatograms showed that the best samples were obtained from the equilibrium vapor above the total condensate removed from the haddock flesh by vacuum distillation. Chromatograms illustrate the changes in the relative amounts of volatile compounds collected from samples of both raw and cooked fish after storage at 2°C for 1, 5, and 10 days. The amount and number of volatile compounds increased during storage, and cooking released additional compounds, some in large amount.

Identification of polyurethanes by high resolution nuclear magnetic resonance spectrometry

“…The higher field multiplet is always attributed to the internal methylene groups, and its chemical shift is less sensitive to the identity of X than is the shift of the CHiX multiplet. (Although these two pairs of methylene groups are chemically equivalent, their protons are not (7) magnetically equivalent, and the complex multiplet patterns are due to strong coupling.) In the butane diol (BD)-based polyurethanes, X is the oxygen atom of the urethane group, and the internal CH2 and CH2Z multiplets appear at 1.68 and 4.13 ppm, respectively.…”

“…They were prepared for the NMR examination by dissolving them in Baker and Adamson reagent grade arsenic trichloride (7) at a concentration of about 15% w/v and by using standard 5-mm o.d. precision glass tubes.…”

Objective Determination of Canned Tuna Quality: Identification of Ethanol as a Potentially Useful Index

“…It has been used to study volatiles in oranges (Schultz, et al, 1971), to follow the ripening of bananas (Tress1 and Jennings, 1972), to characterize different types of cheese (Liebich et al, 1970), and to assess pathological changes in human urine (Zlatkis et al, 1973). In the area of seafoods, the technique has been used to follow flavor changes in cod (Mendelsohn et al, 1966) and to identify substances associated with decomposition of cod (Wong et al, 1967) and of rock. fish (Miller et al, (1972).…”

Gas-chromatographic analysis of dilute aqueous systems

“…tain detectable quantities of dilute vapor components, one must use such a massive quantity of vapor that the injection requires a considerable period of time, and the separated components are in consequence so diluted by carrier gas that they may escape detection. The use of low temperature precolumns has been suggested (3,5,7,8) to permit the concentration of volatiles from head-space vapors prior to their chromatographic separation, but these suffer from obvious disadvantages. While a degree of concentration can be achieved, sufficient diffusion occurs in the pre-column to limit the quantity of gas distillate or head-space vapor that can be used, and in dilute aqueous systems the major volatile in the pre-column is inevitably water, which saturates the pre-column and again limits the quantity of vapor that can be used.…”