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Humic acid

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Humic acid is a natural organic compound derived from the decomposition of organic matter. It is a complex mixture of organic molecules and is a key component of soil and water systems. Humic acid plays a role in various physical and chemical processes in the environment.

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Lab products found in correlation

Sodium hydroxide (naoh), by Merck Group (9 mentions) Sodium chloride (nacl), by Merck Group (6 mentions) Hematin, by Merck Group (6 mentions) Hydrochloric acid (hcl), by Merck Group (5 mentions) Tannic acid, by Merck Group (5 mentions) Acetone, by Merck Group (4 mentions) Milli q system, by Merck Group (4 mentions) Acetonitrile, by Merck Group (4 mentions) Methanol, by Merck Group (4 mentions) Kaolinite, by Merck Group (4 mentions) Acetic acid, by Merck Group (3 mentions) Sodium borohydride, by Merck Group (3 mentions) Nitric acid, by Merck Group (3 mentions) Sodium bicarbonate, by Sinopharm (3 mentions) Salicylic acid, by Merck Group (3 mentions) Formic acid, by Merck Group (3 mentions) Sodium hydroxide (naoh), by Sinopharm (3 mentions) Sodium persulfate, by Merck Group (2 mentions) Bisphenol a, by Merck Group (2 mentions) Hydrogen peroxide, by Merck Group (2 mentions)

Close spelling variants of this product

Humic acids (HAs) (2 citations) Humic acid solution (2 citations) Humic acid sodium salt (14 citations)

110 protocols using humic acid

1

Preparation of NH4+, NO2-, and Humic Acid Solutions

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Analytical grade ammonium chloride salt (NH 4 Cl) and sodium nitrite (NaNO 2 ) were used for the preparation of the stock NH 4
+ and NO 2 -solutions of 2300 mg N/L, respectively. A stock humic acid solution of 1000 mg/L was also prepared using humic acid with chemical formula C 10 H 12 O 5 N (Sigma-Aldrich). Ammonium, nitrite, and humic acid solutions of different concentrations were prepared by diluting the stock solutions with distilled water. The initial pH was adjusted to the desired value using diluted solutions of HCl or NaOH (0.1 N).
Kraiem K., Wahab M.A., Kallali H., Fra-Vazquez A., Pedrouso A., Mosquera-Corral A, & Jedidi N. (2019). Effects of short- and long-term exposures of humic acid on the Anammox activity and microbial community. Environmental science and pollution research international, 26(19).
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2

Inhibitory Substances in Oral Samples

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Several potentially inhibitory substances (toothpaste, mouthwash, beer, tea, tobacco dip, cigarette, and coffee) that are likely to be found in the oral cavity were tested in duplicate. The potential inhibitors were consumed by the donor in a manner consistent with reasonable use prior to sample collection. Oral epithelial samples were then collected from the used cups and bottles as described in “Sample Collection” below. To test blood as a potential inhibitor, 5 and 10 µL aliquots of fingerstick blood from a first donor were dried on ceramic tile, and oral epithelial swabs from a second donor were utilized to collect the blood. A total of four donor pairs were tested. Humic acid (Sigma Cat#53680‐10G) prepared at 0.1, 0.2, 0.4, 0.8, 1.0, 1.5, and 3.0 μg/μL was spiked onto swabs containing 3 µL of dried blood and compared with similar samples without Humic acid. The effect of indigo dye was evaluated by processing bloodstains from both new, unwashed dark blue denim and new, unwashed cotton fabrics. Fabric cuttings of the stains were processed as described in “Sample Collection, Blood on Fabric”). A total of 76 samples were included in the inhibitor study.
Turingan R.S., Tan E., Jiang H., Brown J., Estari Y., Krautz‐Peterson G, & Selden R.F. (2020). Developmental Validation of the ANDE 6C System for Rapid DNA Analysis of Forensic Casework and DVI Samples. Journal of Forensic Sciences, 65(4), 1056-1071.
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3

CuO Nanoparticle Stability in NOM and pH

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Milli-Q water with a constant ionic strength of 10 mM NaCl was used as bulk solution in the study of pH and NOM effects on the stability of CuO NPs. The bulk solution pH was adjusted with HCl or NaOH solution. The ionic strength and ionic valence of Milli-Q water were adjusted with NaCl or CaCl2 solution at a neutral pH. A stock solution of humic acid (Sigma-Aldrich Co., St Louis, MO, USA) with an initial mass concentration of 1000 mg/L was prepared by dissolving humic acid in Milli-Q water and adjusting solution pH to 7.0 ± 0.1. Then the solution was stirred overnight, and filtered through a 0.45 μm cellulose membrane [53 (link)]. The actual dissolved humic acid concentration in the solution was measured at a wavelength of 254 nm using a UV–vis spectrophotometer (Jinghua Technology Instrument Co., Model 752C, Shanghai, China) [48 (link)]. The stock solutions of citric acid and l-cysteine (1000 mg/L) were prepared by dissolving citric acid and l-cysteine in Milli-Q water and adjusting solution pH to 7.0 ± 0.1.
Peng C., Shen C., Zheng S., Yang W., Hu H., Liu J, & Shi J. (2017). Transformation of CuO Nanoparticles in the Aquatic Environment: Influence of pH, Electrolytes and Natural Organic Matter. Nanomaterials, 7(10), 326.
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4

Methanogenic Growth on Humic Acids and Ferrihydrite

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M. acetivorans strain C2A was cultured anaerobically with acetate (90 mM) in high salt (HS) medium buffered with bicarbonate and an atmosphere of N2/CO2 (80%/20%) as described previously (42 (link)). M. orientis sp. nov. was cultured with trimethylamine (30 mM) in DSM 141c medium buffered with bicarbonate and an atmosphere of N2/CO2 (80%/20%) as described previously (43 ). Mid-log phase cultures were anaerobically harvested and thrice washed with HS or DSM 141c media minus acetate or trimethylamine. Media (10 mL) minus acetate or trimethylamine containing humic acids (0.22 g/L) or ferrihydrite (40 mM) was 10% inoculated with washed cells reaching a final concentration of ~107cells/mL. humic acids were purchased from Sigma-Aldrich (CAS No. 1415-93-6). The preparation of electron acceptors is described in SI Appendix. The headspace (40 mL) was filled with 99.9% high-purity methane or 13C-labeled (≥99.0% 13C atom) methane (Isotope, China). The initial pH was 7.2 to 7.4. Incubation was at 37 °C with shaking at 100 rpm.
Yan Z., Du K., Yan Y., Huang R., Zhu F., Yuan X., Wang S, & Ferry J.G. (2023). Respiration-driven methanotrophic growth of diverse marine methanogens. Proceedings of the National Academy of Sciences of the United States of America, 120(39), e2303179120.
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5

Quantifying Fungal Diversity in Soil

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To count the number of growing fungal colonies, soil samples were processed within 15 days from collection, using the Dilution Plate Technique [33 ], partially following the protocol of Landínez-Torres et al. [34 (link)]. Soil dilutions at 10−3 were prepared for four replicates of each sample, and 100 µL of these dilutions were spread on malt extract agar (MEA; Merck KGaA, Darmstadt, Germany) plates. Moreover, in order to estimate the number of fungal strains with strong abilities of degrading recalcitrant materials, fungal counts were also performed on humic acid agar (1 g of commercial humic acids, 3.26 g of Bushnell-Haas broth, 15 g of agar; Merck KGaA, Darmstadt, Germany) and lignocellulose agar (4 g of lignocellulose, 3.26 of Bushnell-Haas broth, 15 g of agar) plates [35 (link)]. Inoculated plates were incubated at 25 °C in the dark and observed every day for 2 weeks. The number of developed fungal colonies was expressed as CFU (Colony-Forming Units) per gram of soil dry weight.
Temporiti M.E., Nicola L., Girometta C.E., Roversi A., Daccò C, & Tosi S. (2022). The Analysis of the Mycobiota in Plastic Polluted Soil Reveals a Reduction in Metabolic Ability. Journal of Fungi, 8(12), 1247.
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6

Synthesis of Iron-Humate Composites

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Humic acid (residue on ignition about 20%), FeCl3.6H2O (96% w/w), FeCl2.4H2O, tetraethoxysilane (TEOS) (Si (OC2H5)4), and ammonia solution (NH−3.H2O) were obtained from Merck Co., Darmstadt, Germany. To prepare and wash the materials, we used absolute ethanol (96%). All the solutions used in this study were prepared using deionized DI-water. To adjust pH, HCl and NaOH solutions (0.1–1.0 M) were applied. The HA concentration was determined using a UV-Visible Spectrophotometer (CECIL-7100, UK). Furthermore, the residues of iron in the solution were measured by means of atomic absorption spectrophotometry (AAS, Shimadzu AA 6800).
Karimi Pasandideh E., Kakavandi B., Nasseri S., Mahvi A.H., Nabizadeh R., Esrafili A, & Rezaei Kalantary R. (2016). Silica-coated magnetite nanoparticles core-shell spheres (Fe3O4@SiO2) for natural organic matter removal. Journal of Environmental Health Science and Engineering, 14, 21.
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7

Bisphenol A and Persulfate Oxidation

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Bisphenol A (BPA, C15H16O2, CAS number: 80-05-7) and sodium persulfate (SPS, Na2S2O8, 99+%, CAS number: 7775-27-1) were purchased from Merck.
Humic acid (technical grade), hydrogen peroxide (30%), sodium chloride (99.8%), sodium hydroxide (98%), boric acid (>99.8%) and sulphuric acid (95%) were also obtained from Merck. Methanol (99.9%) and t-butanol (99%) were purchased from Fluka, while potassium dihydrogen phosphate from Millipore.
All chemicals were used as received, without further purification.
Outsiou A., Frontistis Z., Ribeiro R.S., Antonopoulou M., Konstantinou I.K., Silva A.M.T., Faria J.L., Gomes H.T, & Mantzavinos D. (2017). Activation of sodium persulfate by magnetic carbon xerogels (CX/CoFe) for the oxidation of bisphenol A: Process variables effects, matrix effects and reaction pathways. Water research, 124.
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8

Fabrication of PES-based Nanocomposite Membranes

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PES was obtained from BASF Chemical Co. (Ludwigshafen, Germany). Multiwall carbon nanotubes (MWCNTs) were supplied by Nanocyl SA. (Sambreville, Belgium). The 3-methacryloxypropyl trimethoxysilane (MPS) and titanium tetraisopropoxide (TTIP, 97%) were provided by Wego Chemical Group (New York, NY, USA). N-N-dimethylacetamide (DMAc) and humic acid (HA) were kindly obtained from Sigma Aldrich (St. Louis, MO, USA). Toluene, ethyl alcohol, acetone, HCl, and NaOH were obtained from Merck (Darmstadt, Germany). Deionized (DI) H2O was obtained from water purification system, (Synergy System, Merck). Distilled H2O was obtained from our UMK laboratory. Nitrogen gas was obtained from Wellgas Sdn. Bhd. (Simpang Ampat, Malaysia). The PES was oven-dried at 80 °C for 5 h before use.
Shoparwe N.F., Kee L.C., Otitoju T.A., Shukor H., Zainuddin N, & Makhtar M.M. (2021). Removal of Humic Acid Using 3-Methacryloxypropyl Trimethoxysilane Functionalized MWCNT Loaded TiO2/PES Hybrid Membrane. Membranes, 11(9), 721.
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9

Aqueous Synthesis and Characterization of Zinc Oxide Nanoparticles

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Zinc oxide (CAS No. 1314-13-2, MF: ZnO, MW: 81.39 g/mol), sodium chloride (NaCl), calcium chloride (CaCl2), sodium bicarbonate (NaHCO3), and sodium sulfate (Na2SO4) were purchased from Sigma-Aldrich (USA). Sodium hydroxide (NaOH) was obtained from Daejung Chemicals (South Korea). Sulfuric acid (H2SO4, purity ≥ 96%) was purchased from Kanto Chemicals (Japan). Humic acid (HA) was obtained from Sigma-Aldrich (USA). The HA was dissolved in de-ionized water (DI; ≥ 18.2 Ω cm−1) and filtered through a 0.45-μm hydrophilic polytetrafluoroethylene (PTFE) membrane to produce a stock DOM solution with a concentration of DOC ≈ 10 mg/L. Other solutions were prepared using de-ionized water and diluted as required.
Nguyen T.T., Nam S.N., Kim J, & Oh J. (2020). Photocatalytic degradation of dissolved organic matter under ZnO-catalyzed artificial sunlight irradiation system. Scientific Reports, 10, 13090.
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10

Amphiphilic DADQs for LB Film Fabrication

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Three different amphiphilic DADQs (with single R1 and R2 functional groups structures) for LB film fabrication were used in this study; 1 (2-(4-(5-(hydroxymethyl)-1,3-oxazinan-2-ylidene)cyclohexa-2,5dien-1-ylidene)malononitrile), 2 (2-(4-(4-butyloxazolidin-2-ylidene)cyclohexa-2,5-dien-1ylidene)malononitrile) and 3 (2-(4-((hexylamino)(3-hydroxypyrrolidin-1-yl)methylene)cyclohexa2,5-dien-1-ylidene)malononitrile). Synthetic procedures with characterization for 1, 2 and 3 can be found in the SI section.
For exposure to the LB film surfaces, a few non-fluorescent target analytes were judiciously selected and used without further purification and/or manipulation; Human Serum Albumin (HSA) Sigma Aldrich, Humic Acid (HA) Sigma Aldrich, Nickle Oxide (NiO) Sigma Aldrich, Bisphenol A (Bis A) Sigma Aldrich. All the target analytes were dissolved in deionized water to < 1 mM concentrations and deposited in μL volume droplets to pristine LB film surfaces. The LB films were then left to dry before measurements.
Szablewski M., Thompson R.L, & Pålsson L.O. (2022). Modulated Fluorescence in LB Films Based on DADQs—A Potential Sensing Surface?. Molecules, 27(12), 3893.
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