Univariate and Multivariate Calibration for the Quantitative Determination of Methyl-Parathion in Pesticide Formulations by FT-Raman Spectroscopy

2000 ◽  
Vol 54 (5) ◽  
pp. 747-752 ◽  
Author(s):  
Stavroula G. Skoulika ◽  
Constantinos A. Georgiou
Keyword(s):  
Quantitative Determination ◽  
Methyl Parathion ◽  
Multivariate Calibration ◽  
Band Intensity ◽  
Calibration Data ◽  
Band Area ◽  
Pesticide Formulations ◽  
Relative Standard ◽  
Ft Raman

A Fourier transform (FT)-Raman method for the quantitative determination of methyl-parathion in pesticide formulations is described. The proposed method was applied to the analysis of formulations of methyl-parathion. Univariate and multivariate calibration were used and compared for quantitative analysis. Bands observed at 634, 661, 1113, 1348, and 1527 cm−1 were used for univariate calibration. Calibration curves were linear (correlation coefficients: 0.996–0.998 and 0.994–0.999 for band intensity and band area measurements, respectively) in the concentration range of 0.6–3.75 M for the 634, 661, and 1527 cm−1 bands; 0.05–3.75 M for the 1113 cm−1 band; and 0.1–3.75 M for the 1348 cm−1 band. Precision ranged from 0.5 to 5.2% and 0.1 to 6.8% relative standard deviation (RSD) ( n = 4) for band intensity and band area measurements, respectively. Spectra normalization against the 802 cm−1 cyclohexane band improved the long-term stability of calibration, allowing the use of calibration data acquired 30 days prior to analysis. The application of the method was extended through multivariate calibration by multiple linear regression using the 858 and 2952 cm−1 bands. Results obtained compare well with those obtained by the high-performance liquid chromatography (HPLC) reference method. The FT-Raman method developed is rapid, simple, and safe, as toxic samples are analyzed “as received” without sample pretreatment.

Quantitative Determination of Fenthion in Pesticide Formulations by FT-Raman Spectroscopy

1999 ◽  
Vol 53 (11) ◽  
pp. 1470-1474 ◽  
Author(s):  
Stavroula G. Skoulika ◽  
Constantinos A. Georgiou ◽  
Moschos G. Polissiou
Keyword(s):  
Raman Spectroscopy ◽  
Quantitative Determination ◽  
Pesticide Formulations ◽  
Ft Raman Spectroscopy ◽  
Ft Raman

scholarly journals The effect of pH on the simultaneous determination of Sulfamethoxazole and Trimethoprim by Ultraviolet Spectrophotometry and Multivariate Calibration

2017 ◽  
Vol 1 (2) ◽  
pp. 15-23
Author(s):  
Fabiana E.B. da Silva ◽  
Willian R.R. Almeida ◽  
Fávero R. Paula ◽  
Aline L.H. Müller ◽  
Érico M.M. Flores ◽  
...  
Keyword(s):  
Simultaneous Determination ◽  
High Performance ◽  
Multivariate Calibration ◽  
Analytical Techniques ◽  
Relative Standard Error ◽  
Uv Spectrophotometry ◽  
Calibration Data ◽  
Full Spectrum ◽  
Relative Standard

Analytical techniques based on Ultraviolet (UV) spectrophotometry are widely used in pharmaceutical analysis, because they are simple and inexpensive. The choice of pH is critical in the development of univariate methods for pharmaceutical quantitation by UV spectrophotometry since changes may modify the absorption spectrum profile. Similar to univariate methods by UV spectrophotometry changes in pH may influence the predictive ability of multivariate models, affecting the resultant analytical performance. We report herein on the influence of pH on the simultaneous determination of sulfamethoxazole (SMZ) and trimethoprim (TMP) in tablets using UV spectrophotometry and multivariate calibration. Data were recorded using a UV spectrophotometer in the wavelength range of 200 to 350 nm. The experimental matrix was constructed using 36 synthetic samples of SMZ-TMP mixtures. The concentration ranges used for the investigation were 14.0 to 26.0 mg L-1 for SMZ and 2.8 to 5.2 mg L-1 for TMP. The Partial Least Squares (PLS) regression models were generated with full-spectrum and multiple pH levels. At pH 4.3, lower values of relative standard error of prediction (RSEP %) for SMZ (1.83) and TMP (1.13) were obtained. The PLS model at pH 4.3 was used for the quantification of real samples (tablets obtained from 13 different manufacturers) and the results were compared with conventional procedures using high performance liquid chromatography (HPLC). 

Rapid, Noninvasive Quantitative Determination of Acyclovir in Pharmaceutical Solid Dosage Forms through Their Poly(Vinyl Chloride) Blister Package by Solid-State Fourier Transform Raman Spectroscopy

2003 ◽  
Vol 57 (4) ◽  
pp. 407-412 ◽  
Author(s):  
Stavroula G. Skoulika ◽  
Constantinos A. Georgiou
Keyword(s):  
Raman Spectroscopy ◽  
Fourier Transform ◽  
Dosage Forms ◽  
Band Intensity ◽  
Solid Dosage Forms ◽  
Solid Dosage ◽  
Band Area ◽  
Poly Vinyl Chloride ◽  
Ft Raman

Fourier transform (FT) Raman spectroscopy based on band intensity or band area measurements was used for the quantitative determination of acyclovir in pharmaceutical solid dosage forms through their poly(vinyl chloride) blister package. Univariate calibration using the bands observed at 1690, 1630, 1574, 1482, 1181, 578, and 508 cm−1 was found to be sufficient for the analysis. Calibration curves were linear, the correlation coefficients being 0.997–0.9993 and 0.996–0.9991 for band intensity and band area measurements, respectively. Results obtained compare well, as indicated by the t-test, with those obtained by the current United States Pharmacopoeia (USP 24) and National Formulary (NF 19) method. Precision ranged from 0.7–4.5 and 0.4–4.0% RSD ( n = 3) for band intensity and band area measurements, respectively. The developed nondestructive FT-Raman method is rapid, simple, and can be used for the on-line, real-time monitoring of acyclovir formulation production lines.

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.

Optimization of an Aqueous Two-Phase System for the Determination of Trace Ethyl Carbamate in Red Wine

2019 ◽  
Vol 82 (8) ◽  
pp. 1377-1383 ◽  
Author(s):  
LIJUAN MA ◽  
WENZHE TONG ◽  
LIPING DU ◽  
SHIYONG HUANG ◽  
JINYAN WEI ◽  
...  
Keyword(s):  
Quantitative Determination ◽  
Red Wine ◽  
Ethyl Carbamate ◽  
Phase System ◽  
Extraction Temperature ◽  
Two Phase ◽  
Aqueous Two Phase System ◽  
Relative Standard ◽  
Standard Deviations

ABSTRACT In this study, a novel method using gas chromatography–mass spectrometry coupled with ethanol and K2HPO4 aqueous two-phase system (ATPS) was established for the quantitative determination of trace ethyl carbamate (EC) in red wine. The parameters that influence EC extraction in an aqueous two-phase system, including extraction temperature, time, pH, and ethanol concentration, were optimized. Method validation results indicated that the regression coefficient of the proposed method was 0.9979 in the linear range of 10 to 100 μg/L, and the limits of detection and quantification were 2.8 and 9.2 μg/L, respectively. Four red wine samples made from different grape varieties were processed by the proposed method for the repeatability verification, and EC concentrations were between 15.8 and 37.3 μg/L, with the relative standard deviations ranging from 3.5 to 6.6%. Results of the precision assay showed the average recovery of EC in red wine at 95.4 to 107.1%, with the relative standard deviations ranging from 1.4 to 6.2%. This method proved to be simple and reliable for quantitative determination of trace EC in red wine and would give guidance for quality monitoring of various red wines in the production process.

scholarly journals New Liquid Chromatographic Method for Determination of Rabeprazole Sodium in Coated Tablets

2004 ◽  
Vol 87 (4) ◽  
pp. 842-846 ◽  
Author(s):  
Cássia V Garcia ◽  
Clésio S Paim ◽  
Martin Steppe
Keyword(s):  
Quantitative Determination ◽  
Proton Pump ◽  
Chromatographic Method ◽  
Array Detector ◽  
Liquid Chromatographic Method ◽  
Relative Standard ◽  
Validation Parameters ◽  
Rabeprazole Sodium ◽  
Liquid Chromatographic

Abstract Rabeprazole sodium is a proton pump inhibitor that covalently binds and inactivates the gastric parietal cell proton pump (H+/K+ ATPase). Little has been published about the quantitative determination of this drug. The aim of this research was to develop a new liquid chromatographic method for quantitative determination of rabeprazole in coated tablets. The system consisted of a Hypersil Keystone Betabasic C8 column (250 × 4.6 mm, 5 μm particle size), an isocratic acetonitrile–water (35 + 65) mobile phase at a flow rate of 1.0 mL/min, and a diode array detector set at 282 nm. The following validation parameters were evaluated: linearity, precision, accuracy, specificity, detection and quantitation limits, and robustness. The method showed good linearity in the concentration range of 10–70 μg/mL. The quantitation limit was 2.43 μg/mL, and the detection limit was 0.80 μg/mL. The intra- and interday precision data showed that the method has good reproducibility (relative standard deviation = 1.03). Accuracy and robustness were also evaluated, and the results were satisfactory. The mean recovery was 101.61%. The analysis of a placebo mixture demonstrated the method is also specific.

Reaction-Rate Method for Determining Protein Nitrogen in Grains and Feeds

1979 ◽  
Vol 62 (1) ◽  
pp. 23-28
Author(s):  
Michael S Mccracken ◽  
Howard V Malmstadt
Keyword(s):  
Quantitative Determination ◽  
Reaction Rate ◽  
Mixed Solution ◽  
Protein Nitrogen ◽  
Digestion Procedure ◽  
Relative Standard ◽  
Aoac Method ◽  
Rate Method ◽  
Feed Samples

Abstract In a new automated reaction-rate method for the quantitative determination of protein nitrogen in grains and feeds, the ammonia-sodium phenate-hypochlorite reaction is used for the reaction-rate determination. After samples are digested by the official AOAC block digestion procedure, automated instrumentation is used to precisely and rapidly combine the reactants and transfer the mixed solution to an automated spectrophotometer. The rate of formation of the indophenol during 15 sec at 635 nm is automatically determined and compared with rates obtained for nitrogen standards to determine the protein nitrogen content in the sample. Relative standard deviations of about 0.6% are obtained. Results for grain and feed samples are comparable to those obtained by the official AOAC method.

scholarly journals Simultaneous Determination of Benzene and Toluene in Pesticide Emulsifiable Concentrate by Headspace GC-MS

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Lidong Cao ◽  
Hua Jiang ◽  
Jing Yang ◽  
Li Fan ◽  
Fengmin Li ◽  
...  
Keyword(s):  
Simultaneous Determination ◽  
Internal Standard ◽  
Fused Silica ◽  
Gas Chromatography Mass Spectrometry ◽  
Equilibration Time ◽  
Emulsifiable Concentrate ◽  
Pesticide Formulations ◽  
Relative Standard ◽  
Standard Additions

The toxic inert ingredients in pesticide formulations are strictly regulated in many countries. In this paper, a simple and efficient headspace-gas chromatography-mass spectrometry (HSGC-MS) method using fluorobenzene as an internal standard (IS) for rapid simultaneous determination of benzene and toluene in pesticide emulsifiable concentrate (EC) was established. The headspace and GC-MS conditions were investigated and developed. A nonpolar fused silica Rtx-5 capillary column (30 m×0.20 mmi.d. and 0.25 μm film thickness) with temperature programming was used. Under optimized headspace conditions, equilibration temperature of 120°C, equilibration time of 5 min, and sample size of 50 μL, the regression of the peak area ratios of benzene and toluene to IS on the concentrations of analytes fitted a linear relationship well at the concentration levels ranging from 3.2 g/L to 16.0 g/L. Standard additions of benzene and toluene to blank different matrix solutions 1ead to recoveries of 100.1%–109.5% with a relative standard deviation (RSD) of 0.3%–8.1%. The method presented here stands out as simple and easily applicable, which provides a way for the determination of toxic volatile adjuvant in liquid pesticide formulations.

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