scholarly journals Development of a Rapid Method for the Determination of Caffeine in Coffee Grains by GC-FID-A Fully Validated Approach

2017 ◽  
Author(s):  
Ioannis Pasias ◽  
Ioannis Kyriakou ◽  
Charalampos Proestos
Keyword(s):  
Standard Deviation ◽  
Internal Standard ◽  
Health Claims ◽  
Simple Method ◽  
Iso 17025 ◽  
Real Samples ◽  
Relative Standard ◽  
Commission Regulation ◽  
Independent Parameters

A simple method for the determination of caffeine in coffee grains by GC-FID is presented in the current work. The method was fully validated according to ISO 17025 requirements and European Commission regulation. The accuracy, as provided by recovery experiments was higher than 93%, and the precision, as provided by the (%)Relative standard deviation under reproducibility conditions, was lower than 5%. All independent parameters that lead in the increase of methods uncertainty were investigated. In the present work all special precautions were taken into account in order to avoid the use of an internal standard. The method was applied in real samples and possible health claims were investigated.

scholarly journals Determination of 1,3-Dichloropropanol in Soy Sauce and Related Products by Headspace Gas Chromatography with Mass Spectrometric Detection: Interlaboratory Study

2005 ◽  
Vol 88 (5) ◽  
pp. 1404-1412 ◽  
Author(s):  
Sarah Hasnip ◽  
Colin Crews ◽  
Nicholas Potter ◽  
Paul Brereton ◽  
Henri Diserens ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Internal Standard ◽  
Mass Spectrometric ◽  
Soy Sauce ◽  
Headspace Gas Chromatography ◽  
Relative Standard ◽  
Headspace Gas

Abstract An interlaboratory study was performed to evaluate the effectiveness of a headspace gas chromatography (GC) method for the determination of 1,3-dichloro-propan-2-ol (1,3-DCP) in soy sauce and related products at levels above 5 ng/g. The test portion is mixed with an internal standard (d5-1,3-DCP) and ammonium sulfate in a sealed headspace vial. After achieving equilibrium, the headspace is sampled either by gas-tight syringe or solid-phase microextraction (SPME) and analyzed by GC with mass spectrometric detection. 1,3-DCP is detected in the selected-ion mode (monitoring m/z 79 and 81 for 1,3-DCP and m/z 82 for the deuterated internal standard) and quantified by measurement against standards. Test materials comprising soy, dark soy, mushroom soy, and teriyaki sauces, both spiked and naturally contaminated, were sent to 9 laboratories in Europe, Japan, and the United States; of these, 5 used SPME and 4 used syringe headspace analysis. Test portions were spiked at 5.0, 10.0, 20.0, 100.0, and 500.0 ng/g. The average recovery for spiked blank samples was 108% (ranging from 96–130%). Based on results for spiked samples (blind pairs at 5, 10, 20, 100, and 500 ng/g) as well as a naturally contaminated sample (split-level pair at 27 and 29 ng/g), the relative standard deviation for repeatability (RSDr) ranged from 2.9–23.2%. The relative standard deviation for reproducibility (RSDR) ranged from 20.9–35.3%, and HorRat values of between 1.0 and 1.6 were obtained.

Determination of diltiazem based on the reduction of Cu(II)–BCA complexes in micellar medium

2010 ◽  
Vol 88 (6) ◽  
pp. 533-539 ◽  
Author(s):  
Larissa Zuppardo Lacerda Sabino ◽  
Daniele Cestari Marino ◽  
Horacio Dorigan Moya
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Confidence Level ◽  
Limit Of Detection ◽  
Calibration Graph ◽  
Micellar Medium ◽  
Solution Ph ◽  
Simple Method ◽  
Relative Standard

A simple method was developed for determining microquantities of diltiazem, based on the reduction of copper(II) in buffered solution (pH 7.0) and the use of a micellar medium containing 4,4′-dicarboxy-2,2′-biquinoline acid. The copper(I) produced reacts with 4,4′-dicarboxy-2,2′-biquinoline acid and the complexes formed are spectrophotometrically measured at 558 nm. A typical calibration graph shows good linearity (r = 0.993) from 20 to 100 μg mL–1 of diltiazem. The limit of detection and relative standard deviation were calculated as 12 μg mL–1 (99% confidence level) and 3.5% (40 μg mL–1; n = 6), respectively, with a mean recovery value of 96.5% found in pharmaceutical dosages. A straightforward and effective way to recycle the reagents is addressed. The hazardous aspects of the Cu(I)–BCA reaction are presented as well.

scholarly journals Gas Chromatographic Determination of Acephate in Technical Material and Soluble Powder Formulations: Collaborative Study

1997 ◽  
Vol 80 (3) ◽  
pp. 459-463
Author(s):  
Martin F Kovacs ◽  
H Michael Wehr ◽  
B A Belkind ◽  
J Stein ◽  
O O Bennett ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Broad Spectrum ◽  
Collaborative Study ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Reference Standard ◽  
Standard Samples ◽  
Relative Standard ◽  
Technical Material

Abstract A gas chromatographic (GC) method was developed for quantitation of acephate (Orthene) in technical material and soluble powder formulations. Acephate is an organophosphate with broad spectrum contact and systemic insecticidal properties. Fourteen collaborators from 8 countries participated in a collaborative study of the method. Collaborators were provided with the method; samples of technical acephate and formulated soluble powder containing 95-99% and 71-75% acephate, respectively; an acephate reference standard; and internal standard. Samples were weighed, diluted to volume with internal standard, and quantitated by using GC peak area ratios. Relative standard deviation values for reproducibility (RSDR) were 1.03-2.55 for 95-99% technical acephate and 1.36-2.73 for formulated soluble powder containing 71-75% acephate. The GC method for determination of acephate in technical material and soluble powder formulations has been adopted by AOAC INTERNATIONAL

scholarly journals A simple method for determination of deoxynivalenol in cereals and flours

2011 ◽  
Vol 20 (No. 2) ◽  
pp. 63-68 ◽  
Author(s):  
F. Kotal ◽  
Z. Radová
Keyword(s):  
Regression Analysis ◽  
Standard Deviation ◽  
Limit Of Detection ◽  
Linear Regression Analysis ◽  
Fast Method ◽  
Immunoaffinity Column ◽  
Simple Method ◽  
Relative Standard ◽  
Certified Value

An effective and fast method for determination of deoxynivalenol (DON) in cereals and flours has been developed. The immunoaffinity column was used for the isolation of DON from wheat, corn, rice and flour extract. The determination was carried out by using the HPLC/UV method. The limit of detection was 0.02 mg/kg. The recoveries for the assay range 0.1 to 2 mg/kg were generally higher than 80%, ranging from 83 to 96% with an average relative standard deviation of 3.8%. The trueness of the method using the DON test – HPLC column was established by use of certified reference material CRM 379. The certified value was 0.67 mg/kg. The result obtained from three replicates was 0.68 ± 0.05 mg/kg. The corresponding confidence interval at 95% probability ranged from 0.63 to 0.73 mg/kg. A comparative study of the DON testTM – HPLC/UV and the Mycosep 225 – GC/ECD methods was carried out. Six naturally contaminated wheat samples were analysed by both methods. Linear regression analysis demonstrates that DON testTM – HPLC is a statistically significant predictor of the GC/ECD method using the Romer Mycosep 225 column.  

Gas-Liquid Chromatographic Determination of Fluchloralin in Formulations

1977 ◽  
Vol 60 (5) ◽  
pp. 1145-1147
Author(s):  
Gregory S Grimes
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Reference Standard ◽  
Relative Standard ◽  
Liquid Chromatographic Determination ◽  
Standard Solution ◽  
Liquid Chromatographic

Abstract A gas-liquid chromatographic (GLC) method has been developed that is precise, rapid, simple, and specific for fluchloralin in emulsifiable liquid formulation. Sample and reference standard are weighed, internal standard solution is added, and an aliquot of the mixture is injected onto the chromatographic column. Fluchloralin gives a sharp symmetrical peak at about 5.4 min. The internal standard has a broader symmetrical peak at about 6.9 min. The relative standard deviation for 21 consecutive injections of the standard solution was 0.3773%. The method was compared with the official GLC method, 6.210–6.215, for the structurally similar trifluralin. Fluchloralin gave a sharp symmetrical peak at about 8.5 min; the internal standard had a sharp symmetrical peak at about 9.2 min. The relative standard deviation of 21 consecutive injections of reference standard solution was 0.6988%. Comparison of the variances of the 2 methods by the F-test at the 99% confidence level showed that the proposed method demonstrated substantially better precision.

scholarly journals Simultaneous Determination of N-Butylscopolamine and Oxazepam in Pharmaceutical Formulations by First-Order Digital Derivative Spectrophotometry

2005 ◽  
Vol 88 (4) ◽  
pp. 1173-1178 ◽  
Author(s):  
Maria Inés Toral ◽  
Marcelo A Muñoz ◽  
Sandra L Orellana
Keyword(s):  
Standard Deviation ◽  
Simultaneous Determination ◽  
Relative Standard Deviation ◽  
Pharmaceutical Formulations ◽  
Derivative Spectrophotometry ◽  
Simple Method ◽  
Zero Crossing ◽  
First Order ◽  
Relative Standard

Abstract A simple method has been developed for the simultaneous determination of N-butylscopolamine bromide and oxazepam in pharmaceutical formulations using first-order digital derivative spectrophotometry. Acetonitrile was selected as the solvent in which both compounds showed well-defined bands. Both analytes showed good stability in this solvent when solutions of the analytes were exposed to light and temperatures between 20° and 80°C. The simultaneous determination of both drugs was performed by the zero-crossing method at 226.0 and 257.0 nm for N-butylscopolamine and oxazepam, respectively. The linear range of determination was found to be 2.5 × 10−7 to 8.0 × 10−5 mol/L for N-butylscopolamine and 7.1 × 10−8 to 8.0 × 10−5 mol/L for oxazepam. A very good level of repeatability (relative standard deviation) of 0.2% was observed for N-butylscopolamine and oxazepam. The ingredients commonly found in pharmaceutical formulations do not interfere. The proposed method was applied to the determination of these drugs in pharmaceutical formulations (capsules).

Determination of Flunixin in Swine Plasma, Urine and Feces by UPLCMS/ MS and its Application in the Real Samples

2018 ◽  
Vol 15 (1) ◽  
pp. 51-60 ◽  
Author(s):  
Zugong Yu ◽  
Xiaoqing Luo ◽  
Fanxi Guo ◽  
Zhenrui Zhang ◽  
Lin Peng
Keyword(s):  
Solid Phase ◽  
Multiple Reaction Monitoring ◽  
Parent Compound ◽  
Internal Standard ◽  
Extraction Column ◽  
Real Samples ◽  
Target Drug ◽  
Liquid Liquid Extraction ◽  
Relative Standard

Background: Flunixin is a Non-Steroidal Anti-Inflammatory Drug (NSAID), because it can effectively alleviate the organism of pyrexia, inflammation and pain, it has been widely used in veterinary practice. In order to better study flunixin in the body's absorbed, distributed, metabolized and excreted, our team developed a UPLC-MS/MS method for determination of flunixin in swine plasma, urine and feces. Methods: Flunixin was extracted from the sample by liquid-liquid extraction and cleaned-up using a mixed-mode Oasis MCX solid-phase extraction column. Analysis was performed on UPLC-MS/MS operating in Multiple Reaction Monitoring (MRM) mode. Internal standard was used for quantitation of target drug. Results: Recoveries of fortified samples ranged from 90.2% to 101.4%, with Relative Standard Deviations (RSD) lower than 17.0%. The Limits Of Detection (LODs) and Quantification (LOQs) in plasma were 0.25 and 0.5 µg L-1, in urine were 0.25 and 0.5 µg L-1, and in feces were 0.5 and 1 µg kg-1, respectively. This validated method was successfully applied to the determination of flunixin in real samples. The half-life of flunixin after the last dose in pigs was 7.37±1.60 h after intramuscular administration of 2.2 mg/kg of flunixin, and approximately 6.8% and 1.9% of the administered dose was excreted as parent compound in urine and feces respectively. Conclusion: The developed UPLC-MS/MS method for determination of flunixin in swine plasma, urine and feces was validated and successfully applied to monitor flunixin from real samples.

scholarly journals Determination of Acetochlor in Technical and Formulated Products by Capillary Gas Chromatography

2001 ◽  
Vol 84 (2) ◽  
pp. 317-322
Author(s):  
Bobbi B Kahn ◽  
David F Tomkins
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Method Development ◽  
Internal Standard ◽  
Test Sample ◽  
Weight Percent ◽  
Flame Ionization ◽  
Relative Standard ◽  
Data Points

Abstract A peer-verified gas chromatographic (GC) method is presented for the weight percent (wt %) determination of acetochlor herbicide in technical and formulated products. During method development, the method was found to be rugged by the Youden Ruggedness Test. Two laboratories with experience in the wt % determination of acetochlor in various matrixes participated in this study. Each laboratory received 10 blind duplicate test samples of the following 5 matrixes: one acetochlor technical and 4, different, emulsifiable concentrate (EC) formulations—Harness® EC (MON 5841), Harness ® Export/Fist (MON 8435), Surpass® EC (HF), and Surpass ® EC (LF). Each participant was asked to make duplicate weighings of each of the test samples and to inject each test sample solution twice. All test samples were analyzed on the same day, and 8 data points (replicates) per matrix were obtained. The test samples were dissolved in acetone that contained dipentyl phthalate as an internal standard. They were analyzed by GC on a 15 m capillary column by using split injection and a flame ionization detector. Acetochlor (wt %) was determined by comparing the ratios of peak area of acetochlor/peak area of dipentyl phthalate internal standard obtained for the test sample and calibration solutions. Repeatability of the method, expressed as the within-laboratory (between replicates) relative standard deviation (RSDr), was found to be 0.09–0.77% for the 5 matrixes. Reproducibility of the method, expressed as the within-test sample relative standard deviation (RSDR), was found to be 0.18–0.78% for the 5 matrixes.

scholarly journals Determination of Vitamin B12 in Food Products by Liquid Chromatography/UV Detection with Immunoaffinity Extraction: Single-Laboratory Validation

2008 ◽  
Vol 91 (4) ◽  
pp. 786-793 ◽  
Author(s):  
Esther Campos-Gimnez ◽  
Patric Fontannaz ◽  
Marie-Jose Trisconi ◽  
Tamara Kilinc ◽  
Catherine Gimenez ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Standard Deviation ◽  
Vitamin B12 ◽  
Large Range ◽  
Uv Detection ◽  
Average Standard Deviation ◽  
Simple Method ◽  
Relative Standard ◽  
Single Laboratory

Abstract A fast and simple method to determine vitamin B12 in foods is presented. The method allows, in addition to the determination of added cyanocobalamin, the determination of natural vitamin B12 forms, making it also applicable to nonfortified products, especially those that are milk-based. Vitamin B12 is extracted in sodium acetate buffer in the presence of sodium cyanide (100C, 30 min). After purification and concentration with an immunoaffinity column, vitamin B12 is determined by liquid chromatography with UV detection (361 nm). The method has been validated in analyses of a large range of products: milk- and soy-based infant formulas, cereals, cocoa beverages, health care products, and polyvitamin premixes. The method showed appropriate performance characteristics: linear response over a large range of concentrations, recovery rates of 100.8 7.5 (average standard deviation), relative standard deviation of repeatability, RSDr, of 2.1, and intermediate reproducibility, RSDiR, of 4.3. Limits of detection and quantitation were 0.10 and 0.30 g/100 g, respectively, and correlation with the reference microbiological assay was good (R2= 0.9442). The proposed method is suitable for the routine determination of vitamin B12 in fortified foods, as well as in nonfortified dairy products. It can be used as a faster, more selective, and more precise alternative to the classical microbiological determination.

Colorimetric and Spectrophotometric Determination of Total and Non-phenolic Alkaloids in Ipeca and Its Formulations

1979 ◽  
Vol 62 (5) ◽  
pp. 1113-1115
Author(s):  
Mohamed R I Saleh ◽  
Sawsan El-Masry ◽  
Nagwa El-Shaer
Keyword(s):  
Standard Deviation ◽  
Small Sample ◽  
Acid Extract ◽  
Simple Method ◽  
British Pharmacopoeia ◽  
Total Alkaloids ◽  
Present Procedure ◽  
Relative Standard ◽  
Chloroform Phase

Abstract A simple method, requiring no chromatographic separation, is presented for the determination of the total and non-phenolic alkaloids in ipeca and its preparations. The complex formed between the alkaloid and methyl orange at pH 5.0 is extracted with chloroform and treated with 0.1N NaOH. The liberated dye, determined at 460 nm, is a measure of the total alkaloids. The chloroform phase remaining is treated with 0.1N H2SO4, and the acid extract is measured at 283 nm for the non-phenolic alkaloids, calculated as emetine. The proposed method was successfully applied to samples of ipeca powder, ipeca tincture, and 3 British Pharmaceutical Codex mixtures containing ipeca tincture, namely, ipecacuanha mixture, pediatric; ipecacuanha and ammonia mixture, pediatric; and belladonna and ipecacuanha mixture, pediatric. The proposed method compares favorably with the Egyptian Pharmacopoeia, British Pharmacopoeia, and USP methods and has a relative standard deviation of 1.54%. The present procedure is less time-consuming and requires about 45 and 90 min for the assay of ipeca tincture and powder, respectively. Only a small sample (0.2 mL tincture or 1.0 g powder) is required.

Sign in / Sign up

Export Citation Format

Share Document