scholarly journals Interlaboratory study of the method for direct determination of volatile compounds in alcoholic products using ethanol as internal standard

2020 ◽  
pp. 74-87
Author(s):  
Siarhei V. Charapitsa ◽  
Svetlana N. Sytova ◽  
Anton L. Korban ◽  
Lidia N. Sobolenko ◽  
Vladimir V. Egorov ◽  
...  
Keyword(s):  
Volatile Compounds ◽  
Volatile Component ◽  
Experimental Studies ◽  
Internal Standard ◽  
Direct Determination ◽  
Interlaboratory Study ◽  
Significance Level ◽  
First Time ◽  
Standard Solutions

A collaborative interlaboratory study of the method of direct determination of volatile compounds in spirit drinks and alcoholic products was performed. The proposed method employs ethanol, the major volatile component of an alcoholic product, as an internal standard. For the experiment realization, 9 laboratories from 4 countries – Belarus, Czech Republic, Turkey, Russia – were supplied with standard solutions for gas chromatographic measurements. Five aqueous ethanol 40 % (v/v) standard solutions containing target compounds in concentrations ranging from 10 to 400 mg/L of absolute alcohol were gravimetrically prepared and delivered to the participants. The interlaboratory study was evaluated according to the ISO 5725 standards and the «EuroChem» guide. The repeatability limits (within-laboratory precision) varied between 0.4 and 7.5 % for all samples and compounds, showing a sufficiently high repeatability of the method. The reproducibility limits (between-laboratory precision) were found to vary within a satisfactory range of 0.5–10.0 %. Precision of the method was well within the range predicted by the Horwitz equation for all analytes. In the study experimental estimation of trueness was performed for the first time. Analysis of the obtained results showed that the bias of the method is insignificant at the significance level 5 %. The experimentally determined concentrations of the analytes compared well to the gravimetrical values, thus showing very satisfactory accuracy of the method. The results of the interlaboratory study confirmed that the method «ethanol as internal standard» is robust and reliable and can be used as a standard method for the determination of volatile compounds in water-ethanol samples. Moreover, this method can be validated in any one laboratory without performing additional experimental studies based on the results obtained by validation of the traditional method.

scholarly journals Interlaboratory study of ethanol usage as an internal standard in direct determination of volatile compounds in alcoholic products

2019 ◽  
Vol 15 ◽  
pp. 02030 ◽  
Author(s):  
S. Charapitsa ◽  
S. Sytova ◽  
A. Korban ◽  
L. Sobolenko ◽  
V. Egorov ◽  
...  
Keyword(s):  
Volatile Compounds ◽  
Volatile Component ◽  
Internal Standard ◽  
Direct Determination ◽  
Reference Method ◽  
Interlaboratory Study ◽  
Internal Standard Method ◽  
Significance Level ◽  
Standard Solutions

A collaborative interlaboratory study on the method of direct quantitation of volatile compounds in spirit drinks and alcoholic products was conducted. The discussed method applies ethanol, the major volatile component of an alcoholic product, as an internal standard. In this study 9 laboratories from 4 different countries were supplied with standard solutions for gas chromatographic measurements. Five aqueous ethanol 40% (v/v) standard solutions containing target compounds in concentrations ranging from 10 mg/L to 400 mg/L of absolute alcohol were prepared and sent to the participants for quantification of acetaldehyde, methyl acetate, ethyl acetate, methanol, 2-propanol, 1-propanol, 2-methyl-1-propanol, 1-butanol and 3-methyl-1-butanol. The interlaboratory study was evaluated according to the ISO 5725 standards and the Eurachem guide. The within-laboratory precision varied between 0.4% and 7.5% for all samples and compounds, showing a sufficiently high repeatability of the method. The between-laboratory precision was found to vary within a satisfactory range of 0.5% ÷ 10.0%. Precision of the method was well within the range predicted by the Horwitz equation for all analytes. The analysis of trueness showed that the bias of the method is insignificant at the significance level α = 5%. The determined concentrations of the analytes compared well to the gravimetrical values thus showing very satisfactory accuracy of the method. The results of the interlaboratory study confirmed that “Ethanol as Internal Standard” method is robust and reliable and can be used as a standard reference method for analysing volatile compounds in water-ethanol samples. The possibilities of method validation according to the previously obtained experimental data were shown.

scholarly journals Single-Laboratory Validation of a Gas Chromatographic Method of Direct Determination of Volatile Compounds in Spirit Drinks: Need for an Improved Interlaboratory Study

2019 ◽  
Vol 102 (2) ◽  
pp. 669-672 ◽  
Author(s):  
Siarhei V Charapitsa ◽  
Svetlana N Sytova ◽  
Anton L Korban ◽  
Lidia N Sobolenko
Keyword(s):  
Volatile Compounds ◽  
Chromatographic Method ◽  
Internal Standard ◽  
Direct Determination ◽  
Relative Bias ◽  
Interlaboratory Study ◽  
Detector Response ◽  
Gas Chromatographic Method ◽  
Single Laboratory

Abstract Background: The quality and safety control of an alcoholic drink is mainly the establishment of its chemical content, particularly the quantity of volatile compounds. Objective: A single-laboratory validation of a gas chromatographic method of direct determination of volatile compounds in spirit drinks was conducted. The discussed method applies ethanol, the major volatile component of an alcoholic beverage, as an internal standard. Possible algorithms of method validation based on interlaboratory study were proposed and described. Methods: Seven standard solutions of the following volatile compounds were prepared gravimetrically in 40% (v/v) water–ethanol solution: acetaldehyde, methyl acetate,ethyl acetate, methanol, 2-propanol, 1-propanol, isobutanol, 1-butanol, and isoamylol. Each sample wasmeasured with the proposed method 30 times in repeatability conditions. Results: Flame ionization detector response was linearly correlated with assigned concentrations at a range of 2 to5000 mg/L of absolute alcohol (AA) with coefficients of determination (R2)more than 0.995 for all analyzed components. Repeatability (RSDr ≤ 4.5%; RSDr ≤ 2.0%), reproducibility (RSDR ≤ 5.0%; RSDR ≤ 2.0%), and trueness (relative bias ≤ 2.6%; relative bias ≤ 1.4%) were obtained for low (10–25 mg/L AA for methanol and 2–10 for othervolatiles) and high (25–5000 mg/L AA for methanol and 10–5000 for other volatiles) ranges of concentrations, correspondingly. Conclusions: The method increases the reliability of measurements and eliminates manual proceduresof internal standard addition into both calibrationstandard solutions and spirit drinks.

Simultaneous determination of Rivaroxaban and TAK-438 in rat plasma by LC–MS/MS: application to pharmacokinetic interaction study

Bioanalysis ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 11-22 ◽  
Author(s):  
Libin Wang ◽  
Shouchang Gai ◽  
Xiaorui Zhang ◽  
Xiaohui Xu ◽  
Nan Gou ◽  
...  
Keyword(s):  
Drug Interactions ◽  
Internal Standard ◽  
Pharmacokinetic Interaction ◽  
Rat Plasma ◽  
Pharmacokinetic Parameters ◽  
Interaction Study ◽  
Significant Difference ◽  
Us Fda ◽  
First Time

Aim: A sensitive and reliable LC–MS/MS method has been established and validated to the quantitation of rivaroxaban (RIV) and TAK-438 in rat plasma using carbamazepine as internal standard. Results: The procedure of method validation was conducted according to the guidelines of EMA and US FDA. At the same time, the method was applied to pharmacokinetic interactions study between RIV and TAK-438 for the first time. When RIV and TAK-438 co-administration to rats, main pharmacokinetic parameters of TAK-438 like AUC(0-t), AUC(0-∞) and Cmax had statistically significant increase. The main pharmacokinetic parameters of RIV have no statistically significant difference (p > 0.05) when co-administered except for t1/2 (p < 0.01). Conclusion: The results indicated that drug–drug interactions occurred between RIV and TAK-438 when co-administered to rats.

40Ar/39Ar age and correlation of the nonmarine Two Medicine Formation (Upper Cretaceous), northwestern Montana, U.S.A.

1993 ◽  
Vol 30 (5) ◽  
pp. 1066-1075 ◽  
Author(s):  
Raymond R. Rogers ◽  
Carl C. Swisher III ◽  
John R. Horner
Keyword(s):  
Total Duration ◽  
Direct Determination ◽  
Regional Correlation ◽  
New Radio ◽  
Northwestern Montana ◽  
Judith River Formation ◽  
First Time ◽  
Provincial Park ◽  
Ammonite Zones

The age of the nonmarine Two Medicine Formation of northwestern Montana is currently based upon correlations with K–Ar-dated Western Interior ammonite zones. 40Ar/39Ar dating of biotite and plagioclase separated from four bentonites and one crystal-rich tuff permits for the first time direct determination of the age of Two Medicine strata. Biotite and plagioclase from a bentonite 10 m below the top of the Two Medicine Formation yield concordant 40Ar/39Ar ages of 74 Ma, while biotite and plagioclase from two bentonites and a crystal-rich tuff from approximately 100 m above the base of the formation cluster in age around 80 Ma. The total duration of Two Medicine deposition is estimated using these new radio-isotopic ages via extrapolation of an average rock accumulation rate.The new 40Ar/39Ar ages facilitate regional correlation of the dinosaur-dominated paleofauna recovered from the Two Medicine Formation, and help constrain the timing of the Claggett and Bearpaw transgressions. The ages support correlation of the richly fossiliferous upper lithofacies suite of the Two Medicine Formation with exposures of the Judith River Formation in Dinosaur Provincial Park, Alberta, Canada. Radioisotopically dated exposures of the Judith River Formation within Montana that include important Judithian "age" mammal localities correlate approximately with middle and lower parts of the middle lithofacies suite of the Two Medicine Formation. The new 40Ar/39Ar ages further indicate that the transgressions of the Claggett and Bearpaw seas culminated within northwestern Montana at ca. 79.6 and 74.0 Ma, respectively.

Determination of Sugars in Distilled Spirits by GLC

1968 ◽  
Vol 51 (4) ◽  
pp. 925-927
Author(s):  
Glenn E Martin ◽  
Nicholas K Eib
Keyword(s):  
Reducing Sugars ◽  
Internal Standard ◽  
Distilled Spirits ◽  
Aoac Method ◽  
Standard Solutions

Abstract The anomeric forms of glucose (α and β) and fructose were determined by GLC in both standard solutions and in distilled spirits, using sorbitol as an internal standard. The GLC method for fructose and α and β-glucose compares favorably with the AOAC method for concentrations from about 150 to 225 mg/100 ml. However, at concentrations below 100 mg/100 ml, the GLC method gives generally lower values, probably because the AOAC method measures the amount of reducing sugars and the GLC method measures only α and β-D-glucose and D-fructose

Gas Chromatographic Determination of Total Active Ingredient Content of Karathane Technical and Karathane WD. I. Development of the Method

1970 ◽  
Vol 53 (5) ◽  
pp. 887-895
Author(s):  
C P Kurtz ◽  
H Baum ◽  
C Swithenbank
Keyword(s):  
Active Ingredient ◽  
Silicone Oil ◽  
Internal Standard ◽  
Direct Determination ◽  
Chromatographic Determination ◽  
Working Standard ◽  
Column Temperature ◽  
Glass Column ◽  
In Series

Abstract A new GLC method for the direct determination of the active ingredient in Karathane Technical and Karathane WD is presented. The internal standard (4,6-dinitro-o-cresol) in nitrobenzene solution is added to the sample, or the extract residue in the case of Karathane WD, and the solution is chromatographed on a flame ionization instrument, using an 8’ glass column packed with 3% QF-1 silicone oil on 60–80 mesh Gas Chrom Q. Column temperature is programmed from 100 to 230°C. A working standard of known composition is run in the same manner in series with the sample. The precision of a single determination of the total 2,4- and 2,6-dinitrooctylphenyl crotonate isomers (about 74%) in Karathane Technical and the total dinitrooctylphenols and mononitrooctylphenols (about 6%) is s = 0.5% absolute. Data on the analysis of a limited number of Karathane WD samples show good agreement for the total active ingredient.

Effects of Internal Standards and Peak Profile Functions on Quantitative XRD Phase Analysis of Cement and its Hydrates

2011 ◽  
Vol 492 ◽  
pp. 424-428
Author(s):  
Yong Qi Wei ◽  
Wu Yao ◽  
Wei Wang
Keyword(s):  
Phase Analysis ◽  
Internal Standard ◽  
Direct Determination ◽  
Quantitative Phase Analysis ◽  
X Ray Diffraction ◽  
Profile Function ◽  
Internal Standards ◽  
Refinement Method ◽  
Xrd Phase Analysis

Quantitative X-Ray diffraction (QXRD) combined with the Rietveld refinement method allows direct determination of crystalline phase content of cement and its hydrates. However, relatively precise results need the correction of proper internal standards and the use of matched peak profile functions with masterly refinement strategies. The aim of this paper is to research and discuss effects of these factors on the quantitative phase analysis results. For this purpose, different internal standards and peak profile functions with corresponding refinement strategies were attempted in experiments and refinements. The results indicate that Al2O3as internal standard is more suitable for cement and its hydrates than ZnO, and the better peak profile function is CW function 2 rather than function 3 in GSAS.

Direct determination of N-methyl-2-pyrrolidone metabolites in urine by HPLC-electrospray ionization-MS/MS using deuterium-labeled compounds as internal standard

2009 ◽  
Vol 877 (29) ◽  
pp. 3743-3747 ◽  
Author(s):  
Yoshihiro Suzuki ◽  
Yoko Endo ◽  
Masanori Ogawa ◽  
Shinobu Yamamoto ◽  
Akito Takeuchi ◽  
...  
Keyword(s):  
Electrospray Ionization ◽  
Internal Standard ◽  
Direct Determination ◽  
Labeled Compounds

scholarly journals Effect of grape variety (Vitis vinifera L.) and grape pomace fermentation conditions on some volatile compounds of the produced grape pomace distillate

OENO One ◽  
2004 ◽  
Vol 38 (4) ◽  
pp. 225 ◽  
Author(s):  
Maria Gerogiannaki-Christopoulou ◽  
Nikolaos V. Kyriakidis ◽  
Panagiotis E. Athanasopoulos
Keyword(s):  
Citric Acid ◽  
Vitis Vinifera ◽  
Volatile Compounds ◽  
Internal Standard ◽  
Grape Pomace ◽  
Grape Variety ◽  
Ionization Detector ◽  
Flame Ionization ◽  
Grape Varieties

<p style="text-align: justify;">Agrape pomace distillate was produced from 4 Greek white grape varieties (<em>Vitis vinifera</em> L.). Pomace was fermented with and without addition of citric acid, acting as an antibacterial agent, during fermentation. Fermented grape pomace was distilled in a traditional copper distillation apparatus.. Five major volatile compounds, including methanol, were measured. Pentanol-3 was used as an internal standard. Flame ionization detector (FID) coupled to capillary gas chromatography was used for determination of five volatile distillate components. The addition of citric acid resulted in the reduction of methanol content by about 15%. All the other components studied did not affect in any appreciable degree.</p>

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