The degree of substitution of FA into amino groups in final hydrophobic modified chitosan was determined by a UV/vis spectrophotometer (Analytik Jena, Germany) at 363 nm. Briefly, accurately weighed folate derivative was dissolved in water and DMSO(1/1:v/v) to obtain a 0.02 wt% CMC–FA conjugate solution, and then its optical density was measured with UV/vis spectrophotometer. FA powder was dissolved and diluted to a series of gradient FA standard solutions that were used to prepare the calibration curve. The degree of substitution (DS) was calculated according to the following formula (Wang et al. 2011 (link)): where c is the content of the FA determined from the corresponding calibration curve; m is the amount of the modified polymers used in experiment; MFA is the molecular weight of the FA and MCMCS is the molecular weight of CMC and chitosan units.
Uv vis spectrophotometer
Manufactured by Analytik Jena
Sourced in Germany
The UV/vis spectrophotometer is an analytical instrument that measures the absorbance or transmittance of light by a sample in the ultraviolet and visible light regions of the electromagnetic spectrum. It is used to quantify the concentration of specific compounds in a solution by measuring the amount of light absorbed or transmitted at a specific wavelength.
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Lab products found in correlation
4 protocols using uv vis spectrophotometer
1
Quantifying Folate Conjugation in Chitosan
2
Ultrasonication and Microwave-Assisted Extraction
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Ultrasonicator (VCX-750, Sonics, Sonics and Materials Inc., Newtown, USA) with 20 KHz frequency was used for the UAE purpose. It includes ultrasonic processor with a titanium probe of 13 mm diameter with amplitude (100 %) of 114 μ.Domestic microwave (CE2933, Samsung) working at power level ranged between 300−900 W and frequency of 2450 MHz.
Chromatographic analysis was done by HPLC (Waters Alliance 2695 separation module, equipped with the amino column (Waters, 250 × 4.6 mm, 5 μ), using ELSD (model 2424).
A pH meter and a UV–vis spectrophotometer (Analytik Jena AG, Germany) were used for pH and spectrophotometric analysis respectively. Centrifuge (Z326 K, Hermle AG, Germany) was used for the separation of precipitate.
Chromatographic analysis was done by HPLC (Waters Alliance 2695 separation module, equipped with the amino column (Waters, 250 × 4.6 mm, 5 μ), using ELSD (model 2424).
A pH meter and a UV–vis spectrophotometer (Analytik Jena AG, Germany) were used for pH and spectrophotometric analysis respectively. Centrifuge (Z326 K, Hermle AG, Germany) was used for the separation of precipitate.
3
Fungal Endophyte Antioxidant Activity Assay
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The antioxidant activity of the fungal endophyte’s extracts was measured by the discoloration of methanol solution of DPPH (1,1-diphenyl-2-picryl hydrazyl) radical according to Brand-Willium et al. [20 ]. The scavenging ability of fungal extract was measured by spectroscopically (UV–vis Spectrophotometer, Analytikjena, Germany) at 517 nm. Butylated hydroxyanisole (BHA) and ascorbic acid (Vit C) were used as positive controls. The measurement was carried out in triplicate and averaged. The scavenging ability was calculated by the following method: Results were presented as an IC50 (Concentration of the sample that showed 50% scavenging of the DPPH radical).
4
DPPH Radical Scavenging Assay of T. maxima
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The free radical scavenging ability of T. maxima VLC fractions were screened by measuring the reduced absorbance of methanolic DPPH solution [9] (link). Methanolic DPPH stock solution (20 μg/mL) was added (200 μL) to methanolic sample solution to obtain final 4 ml solution of different concentration (200 μg/mL to 12.5 μg/mL). The absorbance was measured at 517 nm by using UV-VIS spectrophotometer (Analytic Jena AG, Germany) after the solutions were mixed properly and kept in dark for 20 min. The result was expressed using the following formula as the percentage inhibition:
where A 0 is the absorbance of the control and A 1 is the absorbance of the fractions/standard.
where A 0 is the absorbance of the control and A 1 is the absorbance of the fractions/standard.
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