Toc l csh

Total dissolved nitrogen (TDN) and total dissolved phosphorus (TDP) of the extracts were measured using a portable spectrophotometer, Lovibond MD600 (The Tintometer Limited, Amesbury, UK). Each parameter was measured using designated reagents and procedure according to the given instructions in the manual. Dissolved organic carbon (DOC) of extracts was measured as nonpurgeable organic carbon (NPOC) using Shimadzu TOC-L CSH (Shimadzu, Kyoto, Japan) The sample was transferred into a 9 mL vial, and 1% of the total volume of the sample was added with 2 M hydrochloric acid (HCl) to remove volatile carbon. Since the NPOC was measured using high sensitivity catalyst, manual dilution of the concentrated samples was done. Triplicate samples (n = 3) for each treatment were measured for statistical analysis.

Total broth samples (2 mL each) were withdrawn from the reactor and immediately stored at − 80 °C. Supernatant samples were acquired by centrifuging total broth samples (Heraeus Biofuge Pico microcentrifuge) at room temperature for 1 min at 10,400g. The supernatant was then filtrated (pore size 0.2 μm filter, cellulose acetate, FP 30/0.2, Whatman GmbH, Dassel, Germany) and stored at − 80 °C. The total amount of organic carbon (TOC) was quantified with a TOC Analyzer (TOC-L CSH, Shimadzu), using the “difference method”: TOC was calculated from the difference between total carbon and inorganic carbon. Calibration standards were obtained from LPS b.v. (Oss, The Netherlands).

After soil solution sampling, 1‍ ‍mL of 0.5 M sulfuric acid was immediately added to the soil solution sample (approximately 6.5‍ ‍mL). The methane concentration in the headspace of the soil solution sample was analyzed using a gas chromatograph (GC-14A; Shimadzu) fitted with a flame-ionization detector. The dissolved methane concentration of the soil solution was calculated using the headspace methane concentration (Cheng et al., 2005 ). The concentration of dissolved organic carbon (DOC) in the soil solution was analyzed using a total organic carbon analyzer (TOC-LCSH; Shimadzu). The ferrous iron (Fe [II]) concentration in the soil solution was analyzed using inductively coupled plasma optical emission spectrometry (720-ES; Agilent Technologies) in accordance with Suda et al. (2016) . The ana­lysis of dissolved methane and Fe (II) concentrations was conducted for each soil solution sample. The ana­lysis of DOC concentrations was performed using samples collected at 29, 57, 72, and 85 DAT. Concentrations were calculated as the means of four samples from each plot.

Soil microbial biomass carbon (MBC) was evaluated by sieving treatment sub-samples by the chloroform fumigation extraction (CFE) process as pronounced by^{46 (link)}. The extracts obtained were examined for dissolved organic C by a Shimadzu TOC-L CSH with an OCT-L sampler (Shimadzu Corp., Kyoto, Japan) having 5X dilution as designated by^{47 (link)}. Soil microbial biomass C was evaluated using the formula described by⁴⁸ . $$\mathrm{MBC}=({\mathrm{C}}_{\mathrm{fumigated}}{\mathrm{C}}_{\mathrm{control}})/\mathrm{kEC}$$ where, MBC: microbial biomass carbon; kEC: extraction coefficient
The extraction coefficients (kEC) used for carbon to determine MBC was 0.45 as per Potthoff et al.^{49 (link)} and Joergensen et al.^{50 (link)}.

In this method, 1.5 mL of reactant solution was extracted after photo irradiation of organic pollutants in the presence of PEDOT spindles, TiO₂ (P₂₅TiO₂), Ag nanoparticle modified TiO₂ (Ag-TiO₂) diluted in 1 mL of 0.2 M acetoacetanilide in ethanol and 2.5 mL of 4 M ammonium acetate. Consequently, a dihydropyridine has been formed having a maximum absorption wavelength of 368 nm. The absorbance has been measured by a spectrophotometer.
Experiments with the total organic carbon (TOC) technique were conducted to study the mineralization of phenol and MO at different irradiation times. TOC was measured by using a Shimadzu TOC-LCSH. TOC was measured by IR after complete oxidation by catalytic combustion at 680 °C on exclusive platinum catalyst, the inorganic carbon being removed by a previous acidification and air purging.

A total organic carbon
(TOC) analyzer (TOC-L CSH, Shimadzu, Japan) was used to quantify the
nonpurgeable organic carbon (NPOC) in the aqueous samples. The measurement
method involved the injections of 50 μL of sample, a purge time
of 1.5 min and a gas flow of 80 mL min^–1. The organic
carbon is then oxidized to CO₂ over a heated catalyst column
and is then detected by infrared absorbance. For each sample, three
to four measurements were made depending on the standard deviation
of the first three measurements. The TOC analyzer was calibrated daily
between 1 and 20 mg C L^–1, using a potassium terephthalate
TOC standard (Sigma-Aldrich). For the TOC measurements of (NH₄)₂SO₄-methylglyoxal, an imidazole solution
in the same concentration range was prepared to better mimic the organic
compounds in the sample compared to the TOC standard. The TOC values
reported are likely a lower limit as we observed insufficient recovery
of TOC concentrations with known concentrations of lignin, a macromolecule
relevant to biomass burning aerosols (see the Supporting Information (SI) for discussion and Figure S4).