Humic Acid Quantification
Humic Acid Quantification - Related Videos
12:55
Quantification of Humic and Fulvic Acids in Humate Ores, DOC, Humified Materials and Humic Substance-Containing Commercial Products
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Cited by 4 •
2022
This method provides a gravimetric quantification of humic substances (e.g., humic and fulvic acids) on an ash-free basis, in dry and liquid materials from soft coals (i.e., oxidized and non-oxidized lignite and sub-bituminous coal), humate ores and shales, peats, composts and commercial fertilizers and soil amendments.
06:03
Quantification of Endothelial Fatty Acid Uptake using Fluorescent Fatty Acid Analogs
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2025
This protocol details an in vitro assay for measuring cellular lipid uptake in endothelial cells upon stimulation with BODIPY-C12 and BODIPY-C16 fluorescent analogs of long-chain and very long-chain saturated fatty acids. This method is efficient and adaptable to other cell types, offering a useful approach for studying lipid metabolism.
06:55
Simple Bulk Readout of Digital Nucleic Acid Quantification Assays
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Cited by 5 •
2015
We describe an endpoint digital assay for quantifying nucleic acids with a simplified (analog) readout. We measure bulk fluorescence of droplet-based digital assays using a standard qPCR machine rather than specialized instrumentation and confirm our results by microscopy.
04:17
Quantification of Bacterial Alginate Using the Uronic Acid Carbazole Assay
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2025
Source: Al Ahmar, R., et al. Culture of Small Colony Variant of Pseudomonas aeruginosa and Quantitation of its Alginate. J. Vis. Exp. (2020)This video demonstrates a colorimetric assay to quantify alginate produced by Pseudomonas aeruginosa, using carbazole to detect uronic acids after acid hydrolysis. The method enables comparative analysis of alginate production normalized to bacterial biomass in research and clinical studies.
08:12
Characterization, Quantification and Compound-specific Isotopic Analysis of Pyrogenic Carbon Using Benzene Polycarboxylic Acids (BPCA)
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Cited by 40 •
2016
We present the benzene polycarboxylic acid (BPCA) method for assessing pyrogenic carbon (PyC) in the environment. The compound-specific approach uniquely provides simultaneous information about the characteristics, quantity and isotopic composition (13C and 14C) of PyC.
FAQs
Because humic acid is a heterogeneous mixture, its measured amount depends on how the sample’s organic components are separated and how the final signal is interpreted. Different fractions may not respond identically to a spectroscopic measurement, while weighing the recovered material captures a mass-based fraction. Recognizing this heterogeneity is essential when comparing results across samples or studies.
Alkaline extraction transfers humic substances from the original sample matrix into an extract, whereas acid precipitation separates the humic-acid fraction from that extract. Together, these steps simplify the sample before measurement. Their analytical importance is that the final mass or spectroscopic signal is tied to a defined separation workflow rather than to an untreated, chemically mixed sample.
Mass measurement and calibrated spectroscopy provide different forms of quantification. Mass measurement uses the amount of material recovered after separation, while spectroscopy converts a measured signal into an estimate through calibration. The choice affects what is directly observed and how results are interpreted, so the analytical readout should be reported alongside the separation approach used.
A basic workflow begins with the sample, applies alkaline extraction, and then uses acid precipitation to recover the separated humic-acid material. The analyst can then determine the recovered mass or measure a spectroscopic signal against a calibration. Keeping extraction, precipitation, and readout conditions consistent supports meaningful comparisons among soils, sediments, and natural waters.
Sample matrix is a central consideration because humic substances occur in soils, sediments, and natural waters alongside different surrounding materials. Quantification therefore requires attention to the separation step before comparing values. Consistent handling allows measurements to characterize organic-matter composition and supports comparisons among ecosystems without treating every sample as chemically identical.
In biochemistry and environmental research, these measurements help relate humic-substance abundance to broader processes rather than serving only as a concentration value. Results can inform studies of organic-matter composition, carbon cycling, nutrient binding, and pollutant transport. They also help evaluate how humic substances influence chemical and biological processes across different ecosystems.