Development and Validation of Two Methods to Quantify Volatile Acids (C2-C6) by GC/FID: Headspace (Automatic and Manual) and Liquid-Liquid Extraction (LLE)  

作　　者：Maria Angela Tallarico Adorno Julia S. Hirasawa Maria Bernadete Amancio Varesche 

机构地区：[1]Department of Hydraulics and Sanitation, School of Engineering of Sã o Carlos, University of Sã o Paulo, Sã o Carlos, Brazil

出　　处：《American Journal of Analytical Chemistry》2014年第7期406-414,共9页美国分析化学（英文）

摘　　要：The concentration of the volatile fatty acids (VFA) is an important indicator of the status of an-aerobic processes, but most of the existing methods require sample pretreatment and are labor-intensive. It was developed and validated a rapid Gas Chromatographic (GC) method to quantify seven VFA (acetic, propionic, isobutyric, butyric, isovaleric, valeric and caproic), acetone, methanol, ethanol and n-butanol by headspace (automatic and manual) and liquid-liquid extraction (LLE) with diethyl ether (only VFA). The determination was made in a Shimadzu Gas Chromatograph equipped with a Flame Ionization Detector (GC/FID), a headspace auto-sampler and an HP-INNOWAX column. Isobutanol and crotonic acid were utilized as internal standards (IS). The validation parameters evaluated were: precision (coefficient of variation—C.V.% for the retention times, from 0.02 to 0.87), linearity (R2 = 0.9291 - 0.9997), limits of detection (from 3.97 to 36.45 mg·L﹣1) and instrumental precision (from 0.01 to 0.53), which provide evidence that the methods are adequate to determine these analytes in samples from anaerobic reactors and from the environment.The concentration of the volatile fatty acids (VFA) is an important indicator of the status of an-aerobic processes, but most of the existing methods require sample pretreatment and are labor-intensive. It was developed and validated a rapid Gas Chromatographic (GC) method to quantify seven VFA (acetic, propionic, isobutyric, butyric, isovaleric, valeric and caproic), acetone, methanol, ethanol and n-butanol by headspace (automatic and manual) and liquid-liquid extraction (LLE) with diethyl ether (only VFA). The determination was made in a Shimadzu Gas Chromatograph equipped with a Flame Ionization Detector (GC/FID), a headspace auto-sampler and an HP-INNOWAX column. Isobutanol and crotonic acid were utilized as internal standards (IS). The validation parameters evaluated were: precision (coefficient of variation—C.V.% for the retention times, from 0.02 to 0.87), linearity (R2 = 0.9291 - 0.9997), limits of detection (from 3.97 to 36.45 mg·L﹣1) and instrumental precision (from 0.01 to 0.53), which provide evidence that the methods are adequate to determine these analytes in samples from anaerobic reactors and from the environment.

关 键 词：Short Chain Organic ACIDS Gas Chromatography ETHYL Ether ANAEROBIC Processes 

分 类 号：R73[医药卫生—肿瘤]