scholarly journals Spectrophotometric Determination of Iron(II) after Solid Phase Extraction of Its 2,2′ Bipyridine Complex on Silica Gel-Polyethylene Glycol

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Nahid Pourreza ◽  
Saadat Rastegarzadeh ◽  
Ali Reza Kiasat ◽  
Hossein Yahyavi

A new solid phase extraction procedure was developed for preconcentration of iron(II) using silica gel-polyethylene glycol (silica-PEG) as an adsorbent. The method is based on retention of iron(II) as 2,2′ bipyridine complex on silica-PEG. The retained complex is eluted by 1.0 mol L−1of sulfuric acid-acetone mixture (1:2) and its absorbance is measured at 518 nm, spectrophotometrically. The effects of different parameters such as pH, concentration of the reagent, eluting reagent, sample volume, amount of adsorbent, and interfering ions were investigated. The calibration graph was linear in the range of 1–60 ng mL−1of iron(II). The limit of detection based on3Sbwas 0.57 ng mL−1and relative standard deviations (R.S.D) for ten replicate measurements of 12 and 42 ng mL−1of iron(II) were 2.4 and 1.7%, respectively. The method was applied to the determination of of iron(II) in water, multivitamin tablet, and spinach samples.

2011 ◽  
Vol 89 (4) ◽  
pp. 517-523 ◽  
Author(s):  
Ke-Jing Huang ◽  
Cong-Hui Han ◽  
Ying-Ying Wu ◽  
Chao-Qun Han ◽  
De-Jun Niu ◽  
...  

A simple and efficient solid-phase extraction – spectrofluorimetric method has been developed to determine glutathione (GSH). Fluorescent probe N-(4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-yl)methyl)iodoacetamide (BODIPY Fl-C1-IA) was used as the derivatization reagent. The procedure was based on a BODIPY Fl-C1-IA selective reaction with GSH to form the highly fluorescent product BODIPY Fl-C1-IA–GSH, using a solid-phase extraction column and spectrofluorimetric determination. The variables affecting analytical performance were studied and optimized. The calibration graph using the preconcentration system for GSH was linear over the range of 1–200 nmol/L with a limit of detection of 0.05 nmol/L (signal-to-noise ratio = 3). The relative standard deviation for six replicate determinations of GSH at the 100 nmol/L concentration level was 3.9%. The method was applied to water samples and average recoveries between 87.5% and 111.5% were obtained for spiked samples.


1999 ◽  
Vol 82 (1) ◽  
pp. 167-171 ◽  
Author(s):  
Shefali Gosain ◽  
Madhurima Pandey ◽  
Krishna K Verma

Abstract A new reaction for determining iodate in table salt is proposed. It is based on oxidation of phenylhy-drazine-4-sulfonic acid by iodate in acidic medium to the 4-diazobenzenesulfonic acid cation and its electrophilic coupling with N-(1-naphthyl)ethylene- diamine dihydrochloride to give an azo dye, which is measured spectrophotometrically at 545 nm. Maximum molar absorptivity was 8.41 ×104 L/mol cm. A rectilinear calibration graph was obtained for iodate in the range 0.25–5 mg/L. The azo dye could be preconcentrated at least 40-fold by solid-phase extraction on C18 sorbent. The limit of detection was 0.6 μg iodate/L. The method was used to determine iodate in laboratory-prepared and commercially available table salt samples. Up to 5 mg bromate/kg and 10 mg iron(lll)/kg in table salt did not interfere.


2012 ◽  
Vol 9 (3) ◽  
pp. 1550-1561 ◽  
Author(s):  
Saksit Chanthai ◽  
Jureerat Juangsamoot ◽  
Chalerm Ruangviriyachai ◽  
Suchila Techawongstien

Reversed phase-HPLC with fluorescence detection of two major capsaicinoids was described. Isocratic elution using a ratio of methanol and deionized water (66:34, v/v) as mobile phase was used at a flow rate of 0.9 mL/min with well achieved separation within 6 min. Under optimum conditions, their analytical figures of merit for the HPLC method were validated. The linearity was in the range of 1.0-25.0 μg/mL with multiple determination coefficients of higher than 0.995. The limit of detection was ranged of 0.008-0.01 μg/mL. The repeatability and reproducibility of the retention time and peak area for these compounds were in good precision with their relative standard deviations (RSDs) lower than 1% and 5%, respectively. Both capsaicin and dihydrocapsaicin were extracted using an accelerated solvent extraction (ASE) of methanol as an extraction solvent for 5 min static time with 3 cycles. The methanolic extracts were subjected to clean up with C18solid-phase extraction (SPE) with its recoveries ranking of 90.2-98.0%. The method recoveries of real samples were found to be 60.7-98.6%. The optimized extraction method were applied for the determination of the two capsaicinoids in ten vareities of hot chilli pepper samples. Total contents of capsaicinoids were found in the range of 2,307.0-9047.3 μg/g DW with their corresponding Scoville heat unit (SHU) of 34,600-135,700. Additionally, the contents of capsaicinoids using external calibration method comparing with those of standard addition were not significantly different, indicating accuracy of the method. Mostly, the contents of capsaicin found in these real samples were rather higher than those of dihydrocapsaicin.


2012 ◽  
Vol 457-458 ◽  
pp. 536-539 ◽  
Author(s):  
Rui Hua Zhang ◽  
Xiao Li Yang ◽  
Jin Liu ◽  
Xian Zhong Cheng

A simple solid phase extraction procedure for adsorption and preconcentration of manganese(II, VII) in environmental water samples has been proposed prior to inductively coupled plasma mass spectrometry. The procedure presented based on quantitative recoveries of manganese >95%. In this work, the potential use of eggshell membrane(ESM), a typical biomaterial, as solid-phase extraction (SPE) adsorbent is evaluated for analysis of trace manganese. The analytical variables, pH, flow rate, sample volume, elution, coexisting ions for optimum recoveries of manganese (II) and manganese (VII) were investigated. The preconcentration factor was 60. The detection limit (3) of manganese was 0.031 ng L-1. The relative standard deviations of determination was found to be 3.21%. The procedure was successfully applied to the adsorption and determination of manganese in environmental water samples.


2021 ◽  
Vol 44 (02) ◽  
Author(s):  
THANH THUY TRAN ◽  
VAN DAT DOAN ◽  
XUAN HUNG NGUYEN ◽  
UYEN TRUONG

The Mn3O4-TiO2 nanocomposite was applied as a new solid phase adsorbent for preconcentration of Molybdenum before determination by an UV-Vis spectrophotometer. The solid-phase extraction conditions as pH, the mass of sorbent, contact time, stirring speed, and the elution condition were investigated. Under optimized conditions, the adsorption capacity of adsorbent was 20.69 mg/g, and the elution condition was 0.2M NaOH solution. Molybdenum ions were determined based on its catalytic effect on the oxidation of 1-amino-2- naphthol-4-sulfonic acid (ANSA) with H2O2. The linear calibration graph was in the range of 0.2–2.5 µg/L (r2 = 0.995) with a detection limit of 0.0502 µg/L. The relative standard deviation for five measurements of 2 µg/L of Mo (VI) was 3,37%. The method was applied to the determination of Molybdenum in water samples.


2017 ◽  
Vol 6 (2) ◽  
pp. 990-998 ◽  
Author(s):  
Zahra Monsef Khoshhesab

A simple solid phase extraction procedure has been proposed for determination of Au(III) based on separation and preconcentration using magnetite nanoparticles (MNPs) prior to its determination by flame atomic absorption spectrometry. The influences of experimental parameters including sample pH, sorbent mass, contact time, volume and type of eluent, and interference of some ions with extraction of Au(III) ions were investigated using batch procedure. The maximum adsorption capacity of the sorbent for Au(III) was found to be 45.0 mg g-1. The sorption of Au(III) ions was quantitative in the pH range of 4.0–5.0 and quantitative desorption was achieved using 10 mL of thiourea (0.5 mol L-1)/hydrochloric acid (1 mol L-1) solution. In the initial solution, the calibration curve was linear in the range of 8.8 - 666.0 μg L-1 with R2 = 0.9994 (n = 8), the detection limit (3Sb, n = 8) was 6.2 μg L-1, relative standard deviation (R.S.D) of 20 μg mL-1 of Au(III) was 3.9% (n = 8), and the preconcentration factor was 30. The proposed method has been applied to the determination of Au(III) in water and wastewater samples with good recoveries in the range of 95% –103%.


2013 ◽  
Vol 8 (2) ◽  
pp. 1934578X1300800
Author(s):  
Damian Han ◽  
Minglei Tian ◽  
Dong Wha Park ◽  
Kyung Ho Row

A solid-phase extraction (SPE) method for the determination of procatechuic acid, ferulic acid and caffeic acid in Salicornia herbacea L. (Hamcho) has been developed. The optimal conditions were obtained by using a C18 SPE cartridge. By using ethanol and acetonitrile /water/ trifluoracetic acid as washing and eluting solvents, most interfering compounds originating from the hamcho matrix were eliminated. The extracts were sufficiently clean to be directly injected into the HPLC for further chromatographic analysis. Good linearity was obtained from 0.1 to 200 μg/mL (r > 0.999) for procatechuic acid, 0.2 to 400 μg/mL (r > 0.999) for caffeic acid and 0.3 to 600 μg/mL (r > 0.999) for ferulic acid, with the relative standard deviations being less than 3.6%. The mean recoveries of procatechuic acid, ferulic acid and caffeic acid from hamcho were more than 79.2% and the detection limit (S/N = 3:1) was 0.02 μg/mL for procatechuic acid, 0.01 μg/mL for caffeic acid and 0.04 μg/mL for ferulic acid. This method is a viable alternative to the existing HPLC methods for analyzing the content of procatechuic acid, ferulic acid and caffeic acid in hamcho.


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