Quantitative Determination of Carbon Monoxide Residue in Tuna Flesh
Chau-Jen Chow1*, Ping-Ping Hsieh2 and Min-Shou Hwang1
1. National Kaohsiung Institute of Marine Technology, Kaohsiung, Taiwan, R.O. C.
2. Taiwan Provincial Chen-Kung Commercial and Fishery High School, Taitung, Taiwan, R. O. C.
ABSTRACT
An attempt was made to determine the carbon monoxide (CO) residue in tuna flesh being treated with CO gas. Gas chromatography (GC) equipped with a reducing column after the main column to change CO to methane before entering the FID, was used to measure the CO residue. Its determination conditions were discussed. The sensitivity improved 200 times than using GC without a reducing column. Sensitivity limit was about 20 mg/kg of meat. There was a high correlation (r > 0.99) between the response peak area and the amount of CO gas injected. These results suggested that quantitative determination by GC was appropriate. Several tuna flesh having different grade of red color were treated with CO gas for 5 days. Higher CO residue was found in the flesh contained more myoglobin. The molar ratio of CO to Mb was about 11～13%.
Key words: tuna, carbon monoxide, gas chromatography