scholarly journals Approaches to liquid chromatography tandem mass spectrometry assessment of glyphosate residues in wine

2021 ◽  
Author(s):  
L. Pérez-Mayán ◽  
G. Castro ◽  
M. Ramil ◽  
R. Cela ◽  
I. Rodríguez
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Tandem Mass Spectrometry ◽  
Matrix Effects ◽  
Direct Determination ◽  
Reversed Phase ◽  
Multistep Method ◽  
Chromatographic Behavior ◽  
Tandem Mass ◽  
Purification Method

AbstractThe performance of two different analytical methodologies to investigate the presence of glyphosate (GLY) and aminomethylphosphonic acid (AMPA) residues in wine samples was evaluated. Transformation of compounds in their fluorene-9-methyloxycarbonyl derivatives permitted their separation under reversed-phase liquid chromatography with tandem mass spectrometry (LC–MS/MS) determination. Although the wine matrix severely impaired the efficiency of GLY derivatization, this drawback was solved using a molecularly imprinted sorbent for the previous, selective extraction of GLY and AMPA from wine. Alternatively, the use of a strong anionic exchange, polyvinyl alcohol-based LC column, turned to be the most effective alternative for direct determination of both compounds in diluted wine samples. The chromatographic behavior of this column and the magnitude of matrix effects observed during analysis of diluted wine samples were significantly affected by the composition of the mobile phase. Under final working conditions, this column permitted the separation of AMPA and the fungicide fosetyl (which shows common transitions in tandem MS/MS methods), it improved significantly the sample throughput versus extraction-derivatization-purification method, and it allowed the use of solvent-based calibration standards. Both analytical procedures provided similar limits of quantification (LOQs) for GLY (0.5–1.0 ng mL−1), while the multistep method was 8 times more sensitive to AMPA than the direct procedure. GLY residues stayed above method LOQs in 70% of the processed wines; however, concentrations measured in 95% of positive samples remained 100 times below the maximum residue limit (MRL) set for GLY in vinification grapes. Graphical abstract

scholarly journals Determination of Antiviral Drugs and Their Metabolites Using Micro-Solid Phase Extraction and UHPLC-MS/MS in Reversed-Phase and Hydrophilic Interaction Chromatography Modes

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2123
Author(s):  
Luboš Fical ◽  
Maria Khalikova ◽  
Hana Kočová Vlčková ◽  
Ivona Lhotská ◽  
Zuzana Hadysová ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Tandem Mass Spectrometry ◽  
Solid Phase Extraction ◽  
Solid Phase ◽  
Gradient Elution ◽  
Reversed Phase ◽  
Tandem Mass ◽  
Phase Extraction ◽  
Hydrophilic Interaction

Two new ultra-high performance liquid chromatography (UHPLC) methods for analyzing 21 selected antivirals and their metabolites were optimized, including sample preparation step, LC separation conditions, and tandem mass spectrometry detection. Micro-solid phase extraction in pipette tips was used to extract antivirals from the biological material of Hanks balanced salt medium of pH 7.4 and 6.5. These media were used in experiments to evaluate the membrane transport of antiviral drugs. Challenging diversity of physicochemical properties was overcome using combined sorbent composed of C18 and ion exchange moiety, which finally allowed to cover the whole range of tested antivirals. For separation, reversed-phase (RP) chromatography and hydrophilic interaction liquid chromatography (HILIC), were optimized using extensive screening of stationary and mobile phase combinations. Optimized RP-UHPLC separation was carried out using BEH Shield RP18 stationary phase and gradient elution with 25 mmol/L formic acid in acetonitrile and in water. HILIC separation was accomplished with a Cortecs HILIC column and gradient elution with 25 mmol/L ammonium formate pH 3 and acetonitrile. Tandem mass spectrometry (MS/MS) conditions were optimized in both chromatographic modes, but obtained results revealed only a little difference in parameters of capillary voltage and cone voltage. While RP-UHPLC-MS/MS exhibited superior separation selectivity, HILIC-UHPLC-MS/MS has shown substantially higher sensitivity of two orders of magnitude for many compounds. Method validation results indicated that HILIC mode was more suitable for multianalyte methods. Despite better separation selectivity achieved in RP-UHPLC-MS/MS, the matrix effects were noticed while using both chromatographic modes leading to signal enhancement in RP and signal suppression in HILIC.

Vitamin D analyses in veterinary feeds by gas chromatography-tandem mass spectrometry

2021 ◽  
pp. 146906672110002
Author(s):  
Andreas Lehner ◽  
Margaret Johnson ◽  
Alan Zimmerman ◽  
Justin Zyskowski ◽  
John Buchweitz
Keyword(s):  
Mass Spectrometry ◽  
Vitamin D ◽  
Gas Chromatography ◽  
Liquid Chromatography ◽  
Tandem Mass Spectrometry ◽  
Vitamin D3 ◽  
Mass Spectrometric ◽  
Chromatographic Behavior ◽  
Tandem Mass ◽  
Chromatography Tandem Mass Spectrometry

This report examines the feasibility of determination of Vitamin D3, D2 and their 25-hydroxy metabolites utilizing Gas Chromatography Tandem Mass Spectrometry (GC/MS/MS) as a potential alternative to popular Liquid Chromatography Tandem Mass Spectrometric (LC/MS/MS) methodologies. The GC/MS/MS approach was found to operate reasonably well despite long-standing concerns that gas-liquid chromatography of vitamin D compounds invoke thermal rearrangements owing to the relatively high inlet and capillary column temperatures used. The workup procedure involved incubation of feed samples with concentrated potassium hydroxide for overnight fat saponification, extraction of D Vitamins in n-hexane and reaction with N,O-bis(trimethylsilyl)trifluoroacetamide at 70 °C for 30 mins. In addition to parent compounds, small amounts of pyro-, isopyro-, and iso-vitamin D and isotachysterol3 variants were obtained from each Vitamin D-related compound upon extraction and GC/MS/MS analysis. Mass spectral and chromatographic behavior of these compounds are herein described and interpreted. Multiple Reaction Monitoring settings on GC/MS/MS included m/z 456→351 for Vitamin D3 and m/z 486→363 for Vitamin D2. Trimethylsilylation enabled single predominant peaks for Vitamins D3 and D2, and sample workup in the presence of deuterated Vitamin D analogs enabled accurate and precise sensitivity to 1 ppb (ng/g) in feeds. The method could be extended with reasonable accuracy to 25-hydroxy (25OH) compounds, but accuracies would be significantly improved by inclusion of respective 25OH-specific deuterated internal standards. The method was applied to 27 submissions of suspect dog foods of which 22% were discovered elevated and 44% were discovered to contain toxic levels of Vitamin D3. The described method was thus discovered to provide a suitable mass spectrometric approach for Vitamin D, proving itself here specifically of value in detection of ergocalciferol and cholecalciferol in animal feeds. The specificity and sensitivity of the tandem quadrupole approach can enable suitable applicability to serum determination if desired.

Development of a Purification Method for Simultaneous Determination of Deoxynivalenol and Its Acetylated and Glycosylated Derivatives in Corn Grits and Corn Flour by Liquid Chromatography–Tandem Mass Spectrometry

2012 ◽  
Vol 75 (7) ◽  
pp. 1355-1358 ◽  
Author(s):  
TOMOYA YOSHINARI ◽  
TAKAHIRO OHNISHI ◽  
TOMOYUKI KADOTA ◽  
YOSHIKO SUGITA-KONISHI
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Tandem Mass Spectrometry ◽  
Simultaneous Determination ◽  
Tandem Mass ◽  
Corn Flour ◽  
Purification Method ◽  
Chromatography Tandem Mass Spectrometry ◽  
Liquid Chromatography Tandem Mass

We developed a purification method based on liquid chromatography–tandem mass spectrometry for the identification of deoxynivalenol (DON), its acetylated derivatives (3-acetyl-deoxynivalenol and 15-acetyl-deoxynivalenol), and a glycosylated derivative (deoxynivalenol-3-glucoside [D3G]) in corn-based products. The analytes were extracted from samples with acetonitrile-water (85:15, vol/vol) and then purified with multifunctional columns. Evaluation of five kinds of multifunctional columns revealed that DON and its acetylated derivatives were recovered well (96 to 120%) by all columns, but D3G was recovered adequately (93.5%) by only one column, InertSep VRA-3. Samples of corn grits and corn flour were analyzed using the purification method with InertSep VRA-3. DON, D3G, and 15-acetyl-deoxynivalenol were the major contaminants in the samples harvested in 2009, but only DON was detected in the samples harvested in 2010. These results suggest that the purification method using InertSep VRA-3 is effective for identification of DON and its derivatives in corn-based products.

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