Abstract:

A simple, rapid and solvent-free method, headspace solid phase microextraction (HS-SPME) coupled with gas chromatography/mass spectrometry (GC/MS) has been developed for the identification of volatile organic compounds (VOCs) in the manures of cow, hog and chicken. The optimization of SPME conditions and parameters on the effectiveness of analysis and identification of the VOCs has been investigated. The optimal procedures were that 10 g of solid manure and 50 mL of solution saturated by NaCl were added into a vial of 100 mL, stirred at 800 r/min, equilibrated for 30 min and extracted for 30 min at 60 ℃ using a PDMS/DVB fiber, and desorbed at 280 ℃ for 5 min. A total of sixty-six compounds from these three kinds of manures were identified using the NIST library of compound mass spectra. In cow manure, a total of forty-four VOCs were identified as compared to forty in hog manure and forty-one in chicken manure, and among them, sixteen compounds were found to be commonly present. The main components found were: 3-methyl-dodecane (8.18%, peak area percentage), 1-methyl-naphthalene (7.97%) and 3-methyl-1H-indole (7.81%) for the cow manure; 3-methyl-1H-indole (48.89%), 4-methyl-phenol (24.68%) and indole (7.30%) for the hog manure, and 4-ethyl-phenol (13.80%), 4-methyl-phenol (10.67%) and indole (9.77%) for the chicken manure. The results of this study show that HS-SPME-GC/MS is an excellent analytical technique that can be used to identify and analyze VOCs from animal manures. These results also provide a scientific basis to identify off-flavor from animal manures in livestock and poultry industry.

Key words: gas chromatography/mass spectrometry （GC/MS）, manures of cow, hog and chicken , volatile organic compounds （VOCs）, solid phase microextraction （SPME）