scholarly journals Comparison of methods for measuring oxygen in the headspace of a bottle of wine

OENO One ◽  
2004 ◽  
Vol 38 (3) ◽  
pp. 191 ◽  
Author(s):  
Jean-Claude Vidal ◽  
Camille Toitot ◽  
Jean-Claude Boulet ◽  
Michel Moutounet
Keyword(s):  
Gas Chromatography ◽  
Dissolved Oxygen ◽  
Lower Limit ◽  
Indirect Method ◽  
Standard Protocol ◽  
Polarographic Method ◽  
Comparison Of Methods ◽  
Limit Of Quantification ◽  
Before And After ◽  
Polarographic Probe

<p style="text-align: justify;">This paper presents a protocol for the sampling of gases and the measurement of oxygen by the means of a polarographic probe after bottle corking. Analyses of certified standard gases were performed according to the standard protocol of the Office International de la Vigne et du Vin to characterize the polarographic probe and gas chromatography (GC) methods. Finally, analyses of bottles of wine were performed to compare the both methods, together with a method based on the measurement of dissolved oxygen before and after agitation of the bottle of wine.</p><p style="text-align: justify;">The polarographic method displays greater sensitivity and a lower limit of quantification (LQ) than the GC method. Uncertainty was found to be 0.51 % with the probe method. Although the study showed that the results of the indirect method differed from those of the probe and GC methods, especially for high oxygen contents, it enables wine companies to measure oxygen in the wine and in the bottle headspace using the same apparatus.</p>

Eco-Friendly Green Liquid Chromatographic Separations of a Novel Combination of Azelastine and Fluticasone in the Presence of their Pharmaceutical Dosage form Additives

2020 ◽  
Vol 16 (3) ◽  
pp. 277-286
Author(s):  
Amal A. El-Masry ◽  
Mohammed E. A. Hammouda ◽  
Dalia R. El-Wasseef ◽  
Saadia M. El-Ashry
Keyword(s):  
Lower Limit ◽  
Dosage Form ◽  
Limit Of Detection ◽  
Sodium Dodecyl ◽  
Uv Detection ◽  
Simultaneous Estimation ◽  
Limit Of Quantification ◽  
Chromatographic Separations ◽  
Pharmaceutical Dosage Form ◽  
Liquid Chromatographic

Background: The first highly sensitive, rapid and specific green microemulsion liquid chromatographic (MELC) method was established for the simultaneous estimation of fluticasone propionate (FLU) and azelastine HCl (AZL) in the presence of their pharmaceutical dosage form additives (phenylethyl alcohol (PEA) and benzalkonium chloride (BNZ)). Methods: The separation was performed on a C18 column using (o/w) microemulsion as a mobile phase which contains 0.2 M sodium dodecyl sulphate (SDS) as surfactant, 10% butanol as cosurfactant, 1% n-octanol as internal phase and 0.3% triethylamine (TEA) adjusted at pH 6 by 0.02 M phosphoric acid; with UV detection at 220 nm and programmed with flow rate of 1 mL/min. Results: The validation characteristics e.g. linearity, lower limit of quantification (LOQ), lower limit of detection (LOD), accuracy, precision, robustness and specificity were investigated. The proposed method showed linearity over the concentration range of (0.5-25 µg/mL) and (0.1-25 µg/mL) for FLU and AZL, respectively. Besides that, the method was adopted in a short chromatographic run with satisfactory resolution factors of (2.39, 3.78 and 6.74 between PEA/FLU, FLU/AZL and AZL/BNZ), respectively. The performed method was efficiently applied to pharmaceutical nasal spray with (mean recoveries ± SD) (99.80 ± 0.97) and (100.26 ± 0.96) for FLU and AZL, respectively. Conclusion: The suggested method was based on simultaneous determination of FLU and AZL in the presence of PEA and BNZ in pure form, laboratory synthetic mixture and its combined pharmaceutical dosage form using green MELC technique with UV detection. The proposed method appeared to be superior to the reported ones of being more sensitive and specific, as well as the separation was achieved with good performance in a relatively short analysis time (less than 7.5 min). Highly acceptable values of LOD and % RSD make this method superior to be used in quality control laboratories with of HPLC technique.

scholarly journals Application of an LC–MS/MS Method for the Simultaneous Quantification of Homovanillic Acid and Vanillylmandelic Acid for the Diagnosis and Follow-Up of Neuroblastoma in 357 Patients

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3470
Author(s):  
Narae Hwang ◽  
Eunbin Chong ◽  
Hyeonju Oh ◽  
Hee Won Cho ◽  
Ji Won Lee ◽  
...  
Keyword(s):  
Lower Limit ◽  
Large Scale ◽  
Homovanillic Acid ◽  
Limit Of Detection ◽  
Method Comparison ◽  
Vanillylmandelic Acid ◽  
Limit Of Quantification ◽  
Spot Urine ◽  
Minimal Sample ◽  
Clinical Biomarkers

Homovanillic acid (HVA) and vanillylmandelic acid (VMA) are end-stage metabolites of catecholamine and are clinical biomarkers for the diagnosis of neuroblastoma. For the first time in Korea, we implemented and validated a liquid chromatography tandem mass spectrometry (LC–MS/MS) assay to measure urinary concentrations of HVA and VMA according to Clinical and Laboratory Standards Institute guidelines. Our LC–MS/MS assay with minimal sample preparation was validated for linearity, lower limit of detection (LOD), lower limit of quantification (LLOQ), precision, accuracy, extraction recovery, carryover, matrix effect, and method comparison. A total of 1209 measurements was performed to measure HVA and VMA in spot urine between October 2019 and September 2020. The relationship between the two urinary markers, HVA and VMA, was analyzed and exhibited high agreement (89.1% agreement, kappa’s k = 0.6) and a strong correlation (Pearson’s r = 0.73). To our knowledge, this is the first study to utilize LC–MS/MS for simultaneous quantitation of spot urinary HVA and VMA and analyze the clinical application of both markers on a large scale for neuroblastoma patients.

Comparison of methods for reconstruction of gas chromatograms from interferometric gas chromatography/infrared spectrometry data

1981 ◽  
Vol 53 (12) ◽  
pp. 1778-1782 ◽  
Author(s):  
Robert L. White ◽  
Gary N. Giss ◽  
Gregory M. Brissey ◽  
Charles L. Wilkins
Keyword(s):  
Gas Chromatography ◽  
Infrared Spectrometry ◽  
Comparison Of Methods

Determination of multiple organochlorine pesticide residues in shrimp using modified QuEChERS extraction and gas chromatography

2018 ◽  
Vol 16 (1) ◽  
pp. 81-93
Author(s):  
MDH Prodhan ◽  
SN Alam
Keyword(s):  
Gas Chromatography ◽  
Organochlorine Pesticide ◽  
Pesticide Residues ◽  
Limit Of Detection ◽  
Residue Analysis ◽  
Limit Of Quantification ◽  
Modified Quechers ◽  
Endosulfan Sulphate ◽  
Organochlorine Pesticide Residues

Determination of organochlorine pesticide residues in shrimp is very important to ensure the consumer’s safety and to fulfill the importer’s demand. Therefore, a simple and efficient multiple organochlorine pesticide residues analytical method using quick, easy, cheap, effective, rugged and safe (QuEChERS) extraction technique and Gas Chromatography coupled with Electron Capture Detector (ECD) has been developed and validated for the determination of 19 organochlorine pesticides (α- BHC, δ- BHC, β- BHC, γ- BHC, Heptachlor, Aldrin, Heptachlor Epoxide, γ- Chlordane, α- Chlordane, α- Endosulfan, 4,4 DDE, Dieldrin, Endrin, 4,4 DDD, β- Endosulfan, 4,4 DDT, Endosulfan sulphate, Methoxychlor, and Endrin Ketone) in shrimp. The method was validated by evaluating the accuracy, precision, linearity, limit of detection (LOD) and limit of quantification (LOQ). The average recoveries of the selected pesticides ranged from 84% to 106% with RSDr ≤ 14% in four fortification levels of 0.05, 0.1, 0.2 and 0.3 mg kg-1. The linearity was ≥ 0.996 for all of the selected pesticides with matrix matched calibration standards. The LOD ranged from 0.003 to 0.009 mg kg-1 and the LOQ was 0.05 mg kg-1. This method was applied successfully for the residue analysis of 40 shrimp samples collected from different regions in Bangladesh.SAARC J. Agri., 16(1): 81-93 (2018)

scholarly journals A Pilot Study Combining Ultrafiltration with Ozonation for the Treatment of Secondary Urban Wastewater: Organic Micropollutants, Microbial Load and Biological Effects

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3458
Author(s):  
Cátia A. L. Graça ◽  
Sara Ribeirinho-Soares ◽  
Joana Abreu-Silva ◽  
Inês I. Ramos ◽  
Ana R. Ribeiro ◽  
...  
Keyword(s):  
Water Quality ◽  
Estrogenic Activity ◽  
Biological Effects ◽  
Pilot Scale ◽  
Microbial Load ◽  
Organic Micropollutants ◽  
Urban Wastewater ◽  
Limit Of Quantification ◽  
Before And After ◽  
Nematode Eggs

Ozonation followed by ultrafiltration (O3 + UF) was employed at pilot scale for the treatment of secondary urban wastewater, envisaging its safe reuse for crop irrigation. Chemical contaminants of emerging concern (CECs) and priority substances (PSs), microbial load, estrogenic activity, cell viability and cellular metabolic activity were measured before and immediately after O3 + UF treatment. The microbial load was also evaluated after one-week storage of the treated water to assess potential bacteria regrowth. Among the organic micropollutants detected, only citalopram and isoproturon were not removed below the limit of quantification. The treatment was also effective in the reduction in the bacterial loads considering current legislation in water quality for irrigation (i.e., in terms of enterobacteria and nematode eggs). However, after seven days of storage, total heterotrophs regrew to levels close to the initial, with the concomitant increase in the genes 16S rRNA and intI1. The assessment of biological effects revealed similar water quality before and after treatment, meaning that O3 + UF did not produce detectable toxic by-products. Thus, the findings of this study indicate that the wastewater treated with this technology comply with the water quality standards for irrigation, even when stored up to one week, although improvements must be made to minimise microbial overgrowth.

scholarly journals VALIDATION AND ANALYSIS OF DIALLYL DISULFIDE AND DIALLYL TRISULFIDE IN GARLIC (ALLIUM SATIVUM L.) USING GAS CHROMATOGRAPHY

2020 ◽  
pp. 163-166
Author(s):  
HARMITA HARMITA ◽  
HERMAN SURYADI ◽  
LIDWINA DEVIANI LIKASA
Keyword(s):  
Gas Chromatography ◽  
Allium Sativum ◽  
Limit Of Detection ◽  
Diallyl Disulfide ◽  
Diallyl Trisulfide ◽  
Ionization Detector ◽  
Limit Of Quantification ◽  
Flame Ionization ◽  
Precision Limit ◽  
Optimized Conditions

Objective: The purpose of this research was to optimize and validate a method for measuring the levels of diallyl disulfide (DADS) and diallyl trisulfide(DATS) in garlic and single clove garlic.Methods: The analysis was performed using gas chromatography (GC) equipped with an HP-1 column and a flame ionization detector. The initialcolumn temperature was set at 140°C and increased at 1°C/min to 180°C. The injector and detector temperatures were set to 200°C, the carrier gasflow rate was 0.80 mL/min, and the injection volume was 1.0 μL. The optimized conditions of analysis were then validated which included selectivity,linearity, accuracy, precision, limit of detection (LOD), and limit of quantification (LOQ).Results: Using the validated assay and a concentration range of 0.5–20 μg/mL, the coefficient of correlation (r) for DADS was 0.9999 and the LODand LOQ for DADS were 0.3063 μg/mL and 1.0210 μg/mL, respectively. Using the validated assay and a concentration range of 0.5–20 μg/mL, thecoefficient of correlation for DATS was 0.9999 and the LOD and LOQ for DATS were 0.1986 μg/mL and 0.6621 μg/mL, respectively. The percentage ofrecovery was in the range of 98.05–101.76% and coefficient of variation ≤ 2%.Conclusion: This GC method accurately measures the levels of DADS and DATS in garlic.

Sign in / Sign up

Export Citation Format

Share Document