Alternative Spectrofluorimetric Determination of Short-Chain Volatile Fatty Acids in Aqueous Samples

Abstract

This paper presents a simple, rapid, and accurate method suitable for on-site measurement of short-chain volatile fatty acids (SCFA) in various environmental samples. This fluorimetric method involves a derivatization step of SCFA with N-(1-naphthyl)ethylenediamine (EDAN) and allows determination of acetic, butyric, propionic, valeric, lactic, succinic, and p-hydroxybenzoic acids in approximatively 10 min. To evaluate specificity and accuracy of the method, both laboratory-made waters and real samples ranging from wastewater plant and river to soils and composts have been tested. Good accuracy and correlation (r(2) = 0.9887) with HPIC determination have been obtained. The potential interference effect has been taken into account with compounds like humic substances, alcohols, amines, aldehydes, and metallic ions. This method seems thus well designed for the determination of total SCFA in waters, in the range 0.84-500 mg/L. Because this method seems well suited for following of anaerobic treatment, it has been calibrated versus acetic acid-equivalent.

Simple Derivatization–Gas Chromatography–Mass Spectrometry for Fatty Acids Profiling in Soil Dissolved Organic Matter

“…Generally, they are weak acids ranging from 0.46 to 1 million Dalton (Da). Although numerous techniques are devoted to volatile fatty acids (gas, liquid or ion chromatography, titration, mid-infrared spectroscopy) in aqueous samples, none or only few are used for soil leachates characterization [13][14][15][16][17] and are useful for fast total fatty acids monitoring. Most of the above methods either require sophisticated instruments, or are time-consuming or not useful for higher molecular weight fatty acids, making them unsuitable for fatty acids fingerprints.…”

Development of a simple, low-cost and rapid thin-layer chromatography method for the determination of individual volatile fatty acids

“…Our research group has developed an original procedure for the determination of total VFA by batch procedure or microplate assays [22,23]. The analytical methodology is based on a specific derivatization of VFA via a two-step mechanism: (i) activation step with two activating agents at acidic pH; (ii) amidation step with a fluorescent amine at basic pH.…”

Analysis of the lipid profiles in a section of bovine brain via non-catalytic rapid methylation

“…[16][17][18][19][20][21][22][23][24][25][26][27] This derivatization is routinely conducted via the transesterification reaction in the presence of homogeneous catalysts (i.e., KOH/ NaOH/H 2 SO 4 ) at temperatures of 60-63°C, which has been known to be very sensitive to impurities such as water and various extractives. [16][17][18][19][20][21][22][23][24][25][26][27] This derivatization is routinely conducted via the transesterification reaction in the presence of homogeneous catalysts (i.e., KOH/ NaOH/H 2 SO 4 ) at temperatures of 60-63°C, which has been known to be very sensitive to impurities such as water and various extractives.…”

“…The most common lipid profiling of the brain has been conducted via the derivatizing triglycerides (TGs) and phospholipids into fatty acid methyl esters (FAMEs). [16][17][18][19][20][21][22][23][24][25][26][27] This derivatization is routinely conducted via the transesterification reaction in the presence of homogeneous catalysts (i.e., KOH/ NaOH/H 2 SO 4 ) at temperatures of 60-63 °C, which has been known to be very sensitive to impurities such as water and various extractives. 28 Thus, the hierarchical pretreatment steps for the purification of lipids with thin layer chromatography (TLC) must be followed.…”