scholarly journals Rapid Determination of Total Thujone in Absinthe Using 1H NMR Spectroscopy

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
Yulia B. Monakhova ◽  
Thomas Kuballa ◽  
Dirk W. Lachenmeier
Keyword(s):  
Nmr Spectroscopy ◽  
Rapid Determination ◽  
Previous Method ◽  
Rapid Screening ◽  
H Nmr ◽  
Chromatographic Techniques ◽  
Liquid Liquid Extraction ◽  
Relative Standard ◽  
The Eu

1H NMR spectroscopy is utilized to quantify total thujone (sum of α- and β-isomers) in absinthe. For sample preparation, a simple dilution with buffer is required. Thujone produces a distinct peak of the CH2 group in the cyclopentanone moiety in the 2.13–2.11 ppm range. No overlap with other typical constituents such as anethole or fenchone occurs. The detection limit of 0.3 mg/L is adequate to control the EU maximum limit. The relative standard deviation was 6%, and linearity was observed from 1 to 100 mg/L. Applicability was proven by analysis of 69 authentic absinthes. The correlation between NMR and our previous method consisting of liquid-liquid extraction followed by GC/MS was significant (P<0.0001,R=0.93). The simple and cheap NMR method can be used for rapid screening of absinthes for total thujone content while chromatographic techniques are recommended for more specific (α- and β-thujone isomers) analysis if required.

Rapid Determination of Coenzyme Q10 in Food Supplements Using 1H NMR Spectroscopy

2013 ◽  
Vol 83 (1) ◽  
pp. 67-72 ◽  
Author(s):  
Yulia B. Monakhova ◽  
Ingrid Ruge ◽  
Thomas Kuballa ◽  
Christiane Lerch ◽  
Dirk W. Lachenmeier
Keyword(s):  
Nmr Spectroscopy ◽  
Coenzyme Q10 ◽  
Limit Of Detection ◽  
Rapid Determination ◽  
Internal Standard ◽  
Food Supplements ◽  
H Nmr ◽  
Relative Standard ◽  
Liquid Products

A methodology utilizing 1H NMR spectroscopy has been developed to measure the concentration of coenzyme Q10 (CoQ10) in dietary supplements. For sample preparation, a very simple dilution with deuterated chloroform and addition of internal standard is sufficient. CoQ10 produces a distinct peak of the CH groups in the isoprene side chain of the molecule in the δ 5.15 - 5.05 ppm range, where it can be distinguished from other matrix compounds. The method was shown to be of adequate sensitivity with a limit of detection (LOD) of 7.8 mg/L, to control the CoQ10 content in the majority of the products. The precision expressed as relative standard deviation was around 5 %; linearity was observed from 14 to 2000 mg/L (R = 0.99). The developed methodology was applied for the analysis of 21 food supplements (capsules, tablets, and liquid products). On the basis of the labeled amounts, only two products contained substantially lower concentrations of CoQ10 (57 % and 51 %). All other concentrations varied between 83 % and 190 % with respect to labeling. The developed NMR method may be used by quality assurance laboratories for routine control of CoQ10 products.

Rapid determination of total conjugated linoleic acid concentrations in beef by 1 H NMR spectroscopy

2015 ◽  
Vol 41 ◽  
pp. 54-57 ◽  
Author(s):  
Dipesh Prema ◽  
Tyler D. Turner ◽  
Jessica Jensen ◽  
Jessica L. Pilfold ◽  
John S. Church ◽  
...  
Keyword(s):  
Linoleic Acid ◽  
Nmr Spectroscopy ◽  
Conjugated Linoleic Acid ◽  
Rapid Determination ◽  
H Nmr ◽  
Total Conjugated Linoleic Acid

Rapid determination of patulin in medicinal hawthorn fruits by HPLC-MS/MS

2012 ◽  
Vol 5 (1) ◽  
pp. 31-36 ◽  
Author(s):  
L. Xiang ◽  
Y. Gao ◽  
D. Liu ◽  
M. Yang
Keyword(s):  
Rapid Determination ◽  
Multiple Reaction Monitoring ◽  
Internal Standard ◽  
Negative Ion ◽  
Liquid Liquid Extraction ◽  
Relative Standard ◽  
Limit Of Quantitation ◽  
Hawthorn Fruit ◽  
Negative Ion Mode

An HPLC-tandem mass spectrometry method was developed for the determination of patulin (PAT) in dried medicinal hawthorn fruit, a well-known traditional medicine in China. Liquid-liquid extraction was applied in the sample preparation. Multiple reaction monitoring was performed at m/z 153/109 for PAT and m/z 317/273 for internal standard zearalenone in the negative ion mode with electrospray ionisation source. Good linearity was achieved when spiked PAT concentrations were in the range of 10-500 μg/kg, with coefficient being 0.9993. The limit of quantitation was 10 μg/kg. The extraction recoveries for the spiked PAT at concentrations of 20, 100 and 400 μg/kg were 64.5%, 64.6% and 63.9%, respectively, with relative standard deviations of 1.25%, 2.82% and 2.61%. The intra-day and inter-day precision were in the range of 2.2-9.6% and 5.9-6.4%. This rapid, sensitive and reliable method was applied in 25 batches of medicinal hawthorn fruit, in which PAT was detected in 8 batches, including those that were baked or charred.

Rapid determination of γ-value and xanthate group distribution on viscose by liquid-state 1 H NMR spectroscopy

2016 ◽  
Vol 141 ◽  
pp. 184-189 ◽  
Author(s):  
Kateryna Wöss ◽  
Hansjörg Weber ◽  
Peter Grundnig ◽  
Thomas Röder ◽  
Hedda K. Weber
Keyword(s):  
Nmr Spectroscopy ◽  
Liquid State ◽  
Rapid Determination ◽  
H Nmr ◽  
State 1 ◽  
Group Distribution

scholarly journals Rapid Determination of Ethylene Oxide and 75 VOCs in Ambient Air with Canister Sampling and Associated Growth Issues

Separations ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 35
Author(s):  
Jason Hoisington ◽  
Jason S. Herrington
Keyword(s):  
Ethylene Oxide ◽  
Rapid Determination ◽  
Complex Mixture ◽  
Ambient Air ◽  
Gas Chromatography Mass Spectrometry ◽  
Average Accuracy ◽  
Relative Standard ◽  
Wide Range ◽  
Us Epa

A canister-based sampling method along with preconcentrator-Gas chromatography-Mass Spectrometry (GC-MS) analysis was applied to ethylene oxide (EtO or EO) and 75 other volatile organic compounds (VOCs) in ambient air. Ambient air can contain a large variety of VOCs, and thorough analysis requires non-discriminatory sampling and a chromatographic method capable of resolving a complex mixture. Canister collection of whole air samples allows for the collection of a wide range of volatile compounds, while the simultaneous analysis of ethylene oxide and other VOCs allows for faster throughput than separate methods. The method presented is based on US EPA Method TO-15A and allows for the detection of EtO from 18 to 2500 pptv. The method has an average accuracy of 104% and precision of 13% relative standard deviation (RSD), with an instrument run time of 32 min. In addition, a link between canister cleanliness and ethylene oxide growth is observed, and potential mechanisms and cleaning strategies are addressed.

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.

Rapid determination of products of phenol hydrogenation in a supercritical water system using headspace gas chromatography

2015 ◽  
Vol 69 (5) ◽  
Author(s):  
Qing-Qing Guan ◽  
Xiao-Dian Huang ◽  
Yan-Hua Zeng ◽  
Chao-Hai Wei ◽  
Ping Ning ◽  
...  
Keyword(s):  
Supercritical Water ◽  
Rapid Determination ◽  
Reaction System ◽  
Headspace Analysis ◽  
Water System ◽  
Anhydrous Calcium Chloride ◽  
Crystal Water ◽  
Phenol Hydrogenation ◽  
Relative Standard

AbstractThis paper reports a headspace analysis technique for the determination of products, i.e., cyclohexanone (CE) and cyclohexanol (CL), of phenol hydrogenation in a supercritical water reaction system (SWRS) with water removal by hydrate formation. An addition of anhydrous calcium chloride leads to water absorption resulting in crystal water; thus, the samples can be quantitatively measured without the influence of water. After achieving equilibrium at 150­°C and maintaining it for 5 min, the obtained results showed a relative standard deviation of less than 5.3 % and the recovery ranged from 93 % to 104 %. The presented method is simple and accurate for the analysis of CL, CE and phenol in samples from phenol conversion in SWRS.

Rapid determination of sodium hydroxylalkanesulfonate in α-olefin sulfonate by NMR spectroscopy

1974 ◽  
Vol 23 (2) ◽  
pp. 210-212
Author(s):  
Shigeru HASHIMOTO ◽  
Hiroshi TOKUWAKA ◽  
Toshio NAGAI
Keyword(s):  
Nmr Spectroscopy ◽  
Rapid Determination

Rapid Determination of Sulfite by Flow Injection Analysis Based on Fuchsin′s Addition

2013 ◽  
Vol 295-298 ◽  
pp. 950-953 ◽  
Author(s):  
Dong Yuan ◽  
Da You Fu ◽  
Wen Yuan Tan
Keyword(s):  
Flow Injection ◽  
Addition Reaction ◽  
Rapid Determination ◽  
Sampling Rate ◽  
Optimum Conditions ◽  
Linear Calibration ◽  
Relative Standard ◽  
Replicate Measurements ◽  
Good Agreement

A rapid spectrophotometric method for flow injection determination of sulfite in tan wastewater is described. The proposed method was based on the addition reaction of sulfite with fuchsin in Na2B4O7-NaOH medium. The optimum conditions allow a linear calibration range of 0.01-1.20 μg ml-1 SO32-. The detection limit is 0.0023μg ml-1 (S/N=3), and the relative standard deviation for night replicate measurements is 1.1% for 0.5μg ml-1 of sulfite. The sampling rate is 60 samples h-1. The procedure has been applied to the determination of sulfite in tan wastewater. The results were in good agreement with those obtained by pararosaniline method.

Simultaneous Determination of Eight New Generation Amide Insecticide Residues in Complex Matrix Agri-food by Multi-walled Carbon Nanotube Cleanup and UPLC-MS/MS

2021 ◽  
Author(s):  
Tao Lin ◽  
Xinglian Chen ◽  
Li Wang ◽  
Haixian Fang ◽  
Maoxuan Li ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Simultaneous Determination ◽  
High Performance ◽  
Rapid Determination ◽  
Complex Matrix ◽  
Limit Of Quantification ◽  
Relative Standard ◽  
The Matrix ◽  
Multi Walled Carbon Nanotubes

Abstract The simultaneous determination method of 8 amide pesticides by multi-walled carbon nanotubes (MWCNs) cleanup, combined with QuEChERS method and ultra-high performance liquid chromatography-triple quadrupole tandem mass spectrometry has been developed and successfully applied in complex matrix such as green onions, celery, leeks, citrus, lychees, avocado. The matric effect of MWCNs is optimized and compared with QuEChERS materials. The results show that MWCNs can effectively reduce the matrix effect in sample extraction. The mass spectrometry is optimized, through their chemical structure skeletons, the ESI+ and ESI- mode are simultaneously scanned in the method. The coefficient (r) is greater than 0.9990, the limit of quantification ranges from 0.03 to 0.80 μg/kg, the recovery rate ranges from 71.2% to 120%, and the relative standard deviation (RSD) ranges from 3.8% to 9.4%. The method is fast, simple, sensitive, and has good purification effect. It is suitable for the rapid determination of amide pesticides in complex matrix agri-food.

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