An improved method for determining HNMs in drinking water

2013 ◽  
Vol 13 (5) ◽  
pp. 1257-1264 ◽  
Author(s):  
F. Q. Huang ◽  
M. Y. Ruan ◽  
J. D. Yan ◽  
H. C. Hong ◽  
H. J. Lin ◽  
...  
Keyword(s):  
Drinking Water ◽  
Extraction Efficiency ◽  
Tap Water ◽  
Correlation Coefficients ◽  
Method Detection Limit ◽  
Good Reliability ◽  
Liquid Liquid Extraction ◽  
Relative Standard ◽  
Water Ph

Halonitromethanes (HNMs) in drinking water are increasingly becoming a public concern due to their high health risks, so development of a sensitive method for their analysis has become a priority. Liquid–liquid extraction (LLE) method is dominantly used in current studies regarding HNMs. However the sensitivity is far from ideal. The present study aims to investigate the factors that may influence the extraction efficiency during HNM analysis by LLE method, and as a result develop a more sensitive extraction method for HNM determination. Results showed that the dose of sodium sulfate exerted the most significant influence, followed by copper sulfate, while the pH and manual shaking times have little effect. Under the suitable conditions (for extracting HNMs in 45 mL water: pH = 3.5–5, CuSO4 = 1.0 g, Na2SO4 = 6 g, shaking times = 120–180), the correlation coefficients (r) of the calibration curves for nine HNMs were all more than 0.9925. The method detection limit (MDL) ranged from 0.017 to 0.217 μg L−1 with an average of 0.076 μg L−1, which was dominantly lower than the method reported. The recovery (spiked blank samples: 98–108%; spiked tap water: 81–120%) and precision (relative standard deviation: 0.46–6.72) also showed good reliability and reproducibility of the method. Finally, the developed method was applied to the determination of HNMs in real water samples.

scholarly journals Rapid in situ determination of ClO2 in drinking water by improved solid DPD spectrophotometry

2021 ◽  
Vol 252 ◽  
pp. 02063
Author(s):  
Qianqian Zhang ◽  
Lijun Jia ◽  
Tianli Hao ◽  
Ke Zeng
Keyword(s):  
Drinking Water ◽  
Low Cost ◽  
Direct Determination ◽  
Correlation Coefficients ◽  
Good Precision ◽  
Relative Standard ◽  
Relative Errors ◽  
Parallel Tests

This research aims to realize the rapid detection of ClO2 content in drinking water by adopting improved solid DPD. This method is fast and convenient with low cost and less waste liquid. The results show that this method has good precision and sensitivity. The linear correlation coefficients of the cubic regression equation were all greater than 0.999. The detection limit of the method was 0.002mg/L ClO2. The relative standard deviations (RSD) of seven parallel tests were between 1.37% and 8.87%, and the relative errors were small. The recovery rate was 96.67~110%. The method could be used for the direct determination of water samples with a mass concentration of 0.02mg/L~2.00mg/L in drinking water after ClO2 disinfection.

Determination of Tin in Canned Fruits and Vegetables by Atomic Absorption Spectrometry and Liquid–Liquid Extraction

1994 ◽  
Vol 77 (6) ◽  
pp. 1627-1630 ◽  
Author(s):  
Ana M Martín ◽  
Mercedes Sánchez ◽  
Pedro Espinosa ◽  
Gracia Bagur
Keyword(s):  
Aqueous Phase ◽  
Fruits And Vegetables ◽  
Methyl Ketone ◽  
Absorption Spectrometry ◽  
Liquid Extraction ◽  
Acid Complex ◽  
Liquid Liquid Extraction ◽  
Relative Standard ◽  
Good Agreement

Abstract A method was developed for the determination of tin based on the extraction of its 5,5-methylenedisalicylohydroxamic acid complex with 1.09M isobutyl methyl ketone in tributyl phosphate. After the samples were treated with nitric and hydrochloric acid, the aqueous phase was made to 0.05M in perchloric acid. When the ratio of aqueous phase to organic phase was 4:1 (v/v), the detection limit and the relative standard deviation (n = 7,50 μg tin) were 0.20 μg/mL and 0.9%, respectively. The proposed method was applied to the analysis of tin in canned fruits and vegetables. The results were in good agreement with those obtained by the phenylfluorone method.

scholarly journals Simple Spectrophotometric Method for Determination of Paroxetine in Tablets Using 1,2-Naphthoquinone-4-Sulphonate as a Chromogenic Reagent

2009 ◽  
Vol 2009 ◽  
pp. 1-8 ◽  
Author(s):  
Ibrahim A. Darwish ◽  
Heba H. Abdine ◽  
Sawsan M. Amer ◽  
Lama I. Al-Rayes
Keyword(s):  
Spectrophotometric Method ◽  
Correlation Coefficients ◽  
Molar Absorptivity ◽  
Official Method ◽  
Calibration Data ◽  
Pharmaceutical Tablets ◽  
Relative Standard ◽  
Label Claim ◽  
Colored Product

Simple and rapid spectrophotometric method has been developed and validated for the determination of paroxetine (PRX) in tablets. The proposed method was based on nucleophilic substitution reaction of PRX with 1,2-naphthoquinone-4-sulphonate (NQS) in an alkaline medium to form an orange-colored product of maximum absorption peak () at 488 nm. The stoichiometry and kinetics of the reaction were studied, and the reaction mechanism was postulated. Under the optimized reaction conditions, Beer's law correlating the absorbance (A) with PRX concentration (C) was obeyed in the range of 1–8 g . The regression equation for the calibration data was: A = 0.0031 + 0.1609 C, with good correlation coefficients (0.9992). The molar absorptivity () was L  1 . The limits of detection and quantitation were 0.3 and 0.8 g , respectively. The precision of the method was satisfactory; the values of relative standard deviations did not exceed 2%. The proposed method was successfully applied to the determination of PRX in its pharmaceutical tablets with good accuracy and precisions; the label claim percentage was %. The results obtained by the proposed method were comparable with those obtained by the official method.

scholarly journals Spectrophotometric determination of Phenylephrine hydrochloride and Salbutamol sulphate drugs in pharmaceutical preparations using diazotized Metoclopramide hydrochloride

2015 ◽  
Vol 12 (1) ◽  
pp. 167-177 ◽  
Author(s):  
Baghdad Science Journal
Keyword(s):  
Limit Of Detection ◽  
Pharmaceutical Preparations ◽  
Correlation Coefficients ◽  
Limit Of Quantification ◽  
Pharmaceutical Dosage Forms ◽  
Salbutamol Sulphate ◽  
Phenylephrine Hydrochloride ◽  
Relative Standard ◽  
Metoclopramide Hydrochloride

A spectrophotometric method has been proposed for the determination of two drugs containing phenol group [phenylephrine hydrochloride (PHP) and salbutamol sulphate (SLB)] in pharmaceutical dosage forms. The method is based on the diazotization reaction of metoclopramide hydrochloride (MCP) and coupling of the diazotized reagent with drugs in alkaline medium to give intense orange colored product (?max at 470 nm for each of PHP and SLB). Variable parameters such as temperature, reaction time and concentration of the reactants have been analyzed and optimized. Under the proposed optimum condition, Beer’s law was obeyed in the concentration range of 1-32 and 1-14 ?g mL-1 for PHP and SLB, respectively. The limit of detection (LOD) and limit of quantification (LOQ) for each of PHP and SLB were 0.60, 0.52 ?g mL-1 and 2.02, 1.72 ?g mL-1, respectively. No interference was observed from common excipients present in pharmaceutical preparations. The good correlation coefficients and low relative standard deviation assert the applicability of this method. The suggested method was further applied for the determinations of drugs in commercial pharmaceutical preparations, which was compared statistically with reference methods by means of t- test and F- test and were found not to differ significantly at 95% confidence level. The procedure was characterized by its simplicity with accuracy and precision.

scholarly journals Solvent Extraction And Spectrophotomteric Determination Of Cu(Ii) With Dicyclohexyl - 18- Crown-6

2013 ◽  
Vol 10 (3) ◽  
pp. 997-1004
Author(s):  
Baghdad Science Journal
Keyword(s):  
Aqueous Solution ◽  
Solvent Extraction ◽  
Correlation Coefficient ◽  
Extraction Efficiency ◽  
Molar Absorptivity ◽  
Liquid Extraction ◽  
Liquid Liquid Extraction ◽  
Coloured Complex

Liquid-Liquid Extraction of Cu(II) ion in aqueous solution by dicyclohexyl-18-crown-6 as extractant in dichloroethane was studied .The extraction efficiency was investigated by a spectrophometric method. The reagent form a coloured complex which has been a quantitatively extracted at pH 6.3. The method obeys Beer`s law over range from (2.5-22.5) ppm with the correlation coefficient of 0.9989. The molar absorptivity the stoichiometry of extracted complex is found to be 1:2. the proposed method is very sensitive and selective.

scholarly journals Ionic Liquid-modified NiTi Composite Nanosheets Coating for Efficient Solid Phase Microextraction of Octadecylamine in Brine

2019 ◽  
pp. 1-8
Author(s):  
Huiju Wang
Keyword(s):  
Ionic Liquid ◽  
Solid Phase Microextraction ◽  
Extraction Efficiency ◽  
Solid Phase ◽  
Correlation Coefficients ◽  
Fiber Coating ◽  
Relative Standard ◽  
Optimized Conditions ◽  
As Solid Phase

Ionic     liquid (IL), 1-dodecyl-3-methylimidazolium-3-hydroxy-2-naphthoate (C12mimHNC) was synthesized and coated on the surface of NiTi as solid phase microextractiom fiber coating for determination the octadecylamine in brine. Prior to modification with IL, the NiTi was hydrothermally treated for in-situ growth of titanium and nickel oxide composite nanosheets (TiO2/NiOCNSs). The TiO2/NiOCNSs fibers coating was oriented  around the NiTi  substrate and  presented  double-faced  open  access  sites,  which provided a desired support framework for the further modification with IL. The extraction performance of C12mimHNC-TiO2/NiOCNSs fiber coating was evaluated for       detection of octadecylamine (ODA) coupled to HPLC with UV detection. As a result, the C12mimHNC-TiO2/NiOCNSs fiber coating illustrated excellent adsorption and extraction capability for ODA. The main factors affected extraction efficiency were optimized. Under the optimized  conditions,  good  linearity was  obtained  in  the  range of  1-150  µg/L with correlation  coefficients  (r2)  above  0.985.  Limits of detection (LODs) for  the  developed method was 0.280 µg/L. The proposed method was first applied to extract the ODA in brine samples. Relative recoveries varied from 78.3% to 96.5% at spiking level of 15µg/L and 30 µg/L with the relative standard deviations (RSDs) less than 8.7%.

scholarly journals Determination of cyanide in bamboo shoots by microdiffusion combined with ion chromatography–pulsed amperometric detection

2018 ◽  
Vol 5 (4) ◽  
pp. 172128 ◽  
Author(s):  
Ming Ding ◽  
Kailiang Wang
Keyword(s):  
Ion Chromatography ◽  
Limit Of Detection ◽  
Correlation Coefficients ◽  
Amperometric Detection ◽  
High Sensitivity ◽  
Practical Method ◽  
Pulsed Amperometric Detection ◽  
Bamboo Shoots ◽  
Relative Standard

A practical method for the determination of cyanide in bamboo shoots has been developed using microdiffusion preparation integrated with ion chromatography–pulsed amperometric detection (IC-PAD). Cyanide was released from bamboo shoots after Conway cell microdiffusion, and then analysed by IC-PAD. In comparison with the previously reported methods, derivatization and ion-pairing agent addition were not required in this proposed microdiffusion combined with IC-PAD method. The microdiffusion parameters were optimized including hydrolysis systems, temperature, time, and so on. Under the optimum conditions, the linear range of the calibration curve for cyanide was 0.2–200.0 µg kg −1 with satisfactory correlation coefficients of 0.9996 and the limit of detection was 0.2 µg kg −1 ( S/N  = 3). The spiked recovery range was from 92.8 to 98.6%. The intra-day and inter-day relative standard deviations of cyanide were 2.7–14.9% and 3.0–18.3%, respectively. This method was proved to be convenient in operation with high sensitivity, precision and accuracy, and was successfully applied in the determination of cyanide in bamboo shoot samples.

scholarly journals Development and Validation of Spectrophotometric Methods for Determination of Fluoxetine, Sertraline, and Paroxetine in Pharmaceutical Dosage Forms

2005 ◽  
Vol 88 (1) ◽  
pp. 38-45 ◽  
Author(s):  
Ibrahim A Darwish
Keyword(s):  
Correlation Coefficients ◽  
Dosage Forms ◽  
Pharmaceutical Dosage Forms ◽  
Factors Affecting ◽  
Spectrophotometric Methods ◽  
Linear Relationships ◽  
Relative Standard ◽  
Optimum Reaction ◽  
Standard Deviations

Abstract Three simple and sensitive spectrophotometric methods were developed and validated for determination of the hydrochloride salts of fluoxetine, sertraline, and paroxetine in their pharmaceutical dosage forms. These methods were based on the reaction of the N-alkylvinylamine formed from the interaction of the free secondary amino group in the investigated drugs and acetaldehyde with each of 3 haloquinones, i.e., chloranil, bromanil, and 2,3-dichloronaphthoquinone, to give colored vinylamino-substituted quinones. The colored products obtained with chloranil, bromanil, and 2,3-dichloronaphthoquinone exhibit absorption maxima at 665, 655, and 580 nm, respectively. The factors affecting the reactions were studied and optimized. Under the optimum reaction conditions, linear relationships with good correlation coefficients (0.9986–0.9999) were found between the absorbances and the concentrations of the investigated drugs in the range of 4–120 μg/mL. The limits of detection for the assays ranged from 1.19 to 2.98 μg/mL. The precision values of the methods were satisfactory; the relative standard deviations were 0.56–1.24%. The proposed methods were successfully applied to the determination of the 3 drugs in pure and pharmaceutical dosage forms with good accuracy; the recoveries ranged from 99.1 to 101.3% with standard deviations of 1.15–1.92%. The results compared favorably with those of reported methods.

Determination of Aniline, 4-Aminoazobenzene, and 2-Naphthol in the Color Additive D&C Red No. 17 Using Ultra-High-Performance Liquid Chromatography

2018 ◽  
Vol 101 (6) ◽  
pp. 1961-1966 ◽  
Author(s):  
H H Wendy Yang ◽  
Adrian Weisz
Keyword(s):  
High Performance ◽  
Ammonium Acetate ◽  
Correlation Coefficients ◽  
Hplc Method ◽  
Chromatography Method ◽  
Relative Standard ◽  
Data Points ◽  
Color Additive ◽  
The U.S

Abstract Specifications in the U.S. Code of Federal Regulations for the color additive D&C Red No. 17 (R17, Colour Index No. 26100) limit the levels of the dye’s intermediates, aniline (AN), 2-naphthol (β-naphthol, BN), and 4-aminoazobenzene (4AAB), to 0.2, 0.2, and 0.1%, respectively. The present work reports the development and application of an ultra-HPLC method for the quantitative determination of these impurities in R17. A 1.7 μm particle size C-18 column was used with 0.2 M ammonium acetate and acetonitrile as the eluents. AN, BN, and 4AAB were quantified by using six-point calibration curves with data points (w/w) ranging from 0.01 to 0.25% for AN, 0.01 to 0.24% for BN, and 0.01 to 0.19% for 4AAB. The correlation coefficients ranged from 0.9992 to 0.9999. Limits of detection for the analytes ranged from 0.002 to 0.01%. Recoveries of the analytes ranged from 99.5 to 102%. Relative standard deviations ranged from 0.482 to 1.262%. The new method was applied to analyze portions from 22 batches of R17 submitted to the U.S. Food and Drug Administration for certification. It was found to be simpler to implement, faster, and more sensitive than the older gravity-elution column chromatography method, which it has replaced.

scholarly journals Preconcentration of Bismuth(III) and Copper(II) by Solid-Phase Extraction and Subsequent Determination by Differential Pulse Polarography

2001 ◽  
Vol 84 (1) ◽  
pp. 47-52 ◽  
Author(s):  
Anju Bhalotra ◽  
Bal Krishan Prui
Keyword(s):  
Solid Phase ◽  
Supporting Electrolyte ◽  
Saturated Calomel Electrode ◽  
Correlation Coefficients ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Pulse Polarography ◽  
Relative Standard ◽  
Microcrystalline Naphthalene

Abstract A differential pulse polarographic method is proposed for the trace determination of bismuth and copper from large volumes of aqueous samples after adsorption of their 1-(2-thiazolylazo)-2-naphthol complexes onto microcrystalline naphthalene in the pH ranges of 7.2–9.0 and 4.0–7.8, respectively. Bismuth and copper are desorbed from microcrystalline naphthalene with 9 mL 1M HCl. Well-defined peaks are obtained at Ep = −0.09 and −0.20 V versus a saturated calomel electrode, in an HCl–isoquinoline medium as the supporting electrolyte, for bismuth and copper, respectively. Bismuth is reduced reversibly with a 3-electron change, whereas copper is reduced irreversibly under these conditions. The detection limits are 55 ng/mL for bismuth and 91 ng/mL for copper. Linearity is maintained in the concentration ranges of 0.18–13.5 and 0.30-17.3 μg/mL for bismuth and copper, respectively, with corresponding correlation coefficients of 0.9996 and 0.9885. The relative standard deviations are 1.0% for bismuth at 2.0 μg/mL and 1.4% for copper at 5.0 μg/mL. Various parameters were optimized to develop conditions for the determination of these metal ions in various samples.

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