High-performance liquid chromatography (HPLC) was used to assess the AtRA release kinetics. Previously AtRA loaded POC coated- CoCr stents (13mm in length) were incubated in 350μL nanopure water within amber vials for 7 days at 37°C. At 24 hr. increments, the entire 350μL water volume containing released AtRA was removed and replaced with fresh nanopure water. The 24hr aliquots were transferred into 400μl low volume HPLC vials and stored at −80°C. For quantification of released AtRA, the aliquots were lyophilized to remove the water then the released AtRA was dissolved in acetonitrile. A Shimadzu HPLC system with a photodiode array detector (Shimadzu, Columbia, MD) and an Ascentis RP-Amide column (150 mm x 2.1mm, 3μm particle size) (Sigma-Aldrich, St. Louis, MO) was used to quantify the AtRA concentration. HPLC grade water (solvent A) and acetonitrile (solvent B) both containing 0.1% (vol/vol) formic acid formed the solvent system. Flowrate was set at 400 μL/min and the gradient was programmed as: 70% B (0–15 min), 70% to 95% B (15–20 min), 95% B (20–21 min), 95% to 70% B (21–25 min) and re-equilibrate at 70% B. AtRA was monitored by the photodiode array detector at 350 nm and compared to a standard curve of known concentration, based on the peak area of retinoic acid.
Ascentis rp amide column
Manufactured by Merck Group
Sourced in Japan, United States
The Ascentis RP-Amide column is a type of reversed-phase liquid chromatography column designed for the separation and analysis of a variety of sample components. It features a silica-based stationary phase with an amide-modified surface chemistry.
Automatically generated - may contain errors
Lab products found in correlation
Photodiode array detector, by Shimadzu (1 mentions)
Hplc system, by Shimadzu (1 mentions)
Agilent 1100 series, by Agilent Technologies (1 mentions)
Inova 500, by Agilent Technologies (1 mentions)
Safire microplate reader, by Tecan (1 mentions)
Nicolet nexus 870 spectrometer, by Thermo Fisher Scientific (1 mentions)
Rotavapor r 205, by Büchi (1 mentions)
Spd 20a, by Shimadzu (1 mentions)
Hp agilent 1200, by Agilent Technologies (1 mentions)
5 protocols using ascentis rp amide column
1
HPLC Analysis of AtRA Release Kinetics
2
Quantification of Carbamazepine and Diclofenac using HPLC
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CBZ and DCF concentration were determined using high-performance liquid chromatography (HPLC) equipment from Agilent technologies (Agilent 1100 Series) (Bad Homburg v. d. Höhe, Germany). As stationary phase, a 5 µm Ascentis RP-Amide column, with a length of 150 mm and a diameter of 4.6 mm (Sigma-Aldrich) was used. The ultraviolet detector worked at a wavelength of 220 nm for CBZ and 286 nm for DCF. The mobile phase consisted of a mixture of acetonitrile and water (v:v = 55:45 for CBZ and v:v = 65:35 for DCF) with 1 mL of ortho-phosphoric acid, at a flow of 1.0 mL min−1 with a detection time of 180 s for CBZ and 210 s for DCF.
Studies by several authors [86 (link),87 (link),88 (link)] for direct reactions of ozone with several drinking water contaminants noted that acetonitrile can affect radical processes by scavenging hydroxyl radicals, albeit relatively slowly (k = 2.2 × 107 M−1 s−1).
The linearity of the calibration curves was verified using standard solutions in the concentration range of 0.01–5.0 mg L−1; linear R-square values higher than 0.999 were obtained. Each standard was injected in triplicate. The limits of detection (LOD) and limits of quantification (LOQ) of the pharmaceutical products were: LOD and LOQ of CBZ were 0.02 mg L−1 and 0.06 mg L−1 and for DCF the values were 0.01 mg L−1 for LOD and 0.03 mg L−1 for LOQ.
Studies by several authors [86 (link),87 (link),88 (link)] for direct reactions of ozone with several drinking water contaminants noted that acetonitrile can affect radical processes by scavenging hydroxyl radicals, albeit relatively slowly (k = 2.2 × 107 M−1 s−1).
The linearity of the calibration curves was verified using standard solutions in the concentration range of 0.01–5.0 mg L−1; linear R-square values higher than 0.999 were obtained. Each standard was injected in triplicate. The limits of detection (LOD) and limits of quantification (LOQ) of the pharmaceutical products were: LOD and LOQ of CBZ were 0.02 mg L−1 and 0.06 mg L−1 and for DCF the values were 0.01 mg L−1 for LOD and 0.03 mg L−1 for LOQ.
3
Quantitative Analysis of Atrazine Removal
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The atrazine concentration was determined using High-Performance Liquid Chromatography (HPLC) equipment from Agilent technologies, specifically, an Agilent 1100 Series machine. The equipment has a 5 μm Ascentis RP-Amide column (150 mm x 4.6 mm) from Sigma-Aldrich as its stationary phase and an ultraviolet detector (UV), with a working wavelength of 220 nm. The mobile phase consisted of a mixture of acetonitrile and water (v:v = 60:40), at a flow of 1.0 ml min -1 with a detection time of 210s. The matrix used for the study was Type I ultrapure water (ASTM, 2018), supplied by Milli-Q Academic (Millipore), with a pH of 6.7.
Calibration standards with concentration in the 0.01-5.0 mg L -1 range were used. Each standard was injected in triplicate. Linearity was checked in the concentration range studied through a regression analysis by the method of least squares. For the calibration, linear R-square values higher than 0.999 were obtained. The limits of detection (LOD) and quantification (LOQ) were experimentally estimated as the lowest concentration level able to reach a signal to noise ratio of 0.01 mg L -1 for LOD and 0.03 mg L -1 for LOQ.
The atrazine removal was determined according to the following equation (1):
Where:
C o : Initial atrazine concentration in the feedstock (mg L -1 ).
C f : Atrazine concentration in in a given time of treatment (mg L -1 ).
Calibration standards with concentration in the 0.01-5.0 mg L -1 range were used. Each standard was injected in triplicate. Linearity was checked in the concentration range studied through a regression analysis by the method of least squares. For the calibration, linear R-square values higher than 0.999 were obtained. The limits of detection (LOD) and quantification (LOQ) were experimentally estimated as the lowest concentration level able to reach a signal to noise ratio of 0.01 mg L -1 for LOD and 0.03 mg L -1 for LOQ.
The atrazine removal was determined according to the following equation (1):
Where:
C o : Initial atrazine concentration in the feedstock (mg L -1 ).
C f : Atrazine concentration in in a given time of treatment (mg L -1 ).
4
Analytical Techniques for Compound Characterization
5
Analytical HPLC Purity Assessment of Extracts
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Analytical HPLC was used to assess the purity of the extract during each step of the isolation procedure. The instrument used was an HP Agilent 1200 analytical HPLC system (HP/Agilent, Santa Clara, USA) equipped with a diode array detector at 520 nm and 280 nm, and a 250 × 25 mm (4.5 µm particle size) Ascentis RP-Amide column (Supelco, Bellefonte, USA. The mobile phases were A, 1% TFA in water (v/v), and B, 1% TFA in acetonitrile (v/v), used at a flow of 1 mL/min. A solvent elution profile consisted of initial conditions of 30% B and the following isocratic and gradient elution: 0–7 min gradient to 40% B, 7–10 min gradient to 50% B, 10–15 min isocratic, 15–17 min gradient to 80% B, 17–22 min isocratic, and 22–25 min gradient to 30%. Injections were 20 µL aliquots injected by an auto-sampler. Prior to injections, samples were filtered through a 0.45 µm filter.
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