Navigation Links
Fast Analysis of Phenoxyacetic and Phenoxypropionic Herbicides in Vegetable Matrix by Negative Ion Electrospray LC/MS/MS

P.Y. Communal and A. Royer, Girpa, Angers, France
C. Schauber and T. Faye, Varian, Inc., France

Introduction

Phenoxy acids are used as herbicides in agricultural and domestic areas. These compounds have to be detected at trace level to ensure a safe drinking water and food supply and verify appropriate remediation of these pollutants from contaminated sites.

Among the analytical methods developed, LC/UV exhibits poor sensitivity and inadequate selectivity for complex vegetable matrices. Negative ion ESI LC/MS has exceptionally high sensitivity for these herbicides and, with the added selectivity of MS/MS, provides accurate analyses even for the most complex sample matrices.

A highly sensitive and fast method is described below for high throughput identification and quantitation four common herbicides in vegetable extracts (Figure 1).

Instrumentation

Varian ProStar 410 AutoSampler

Varian ProStar 210 Solvent Delivery Modules

Varian 1200L LC/MS with ESI source

Materials and Reagents

Standard solutions: pesticides were provided by the GIRPA group, France. ASE 300 (Dionex)

Florisil (Carlo Erba)

Hydromatrix bulk material (Varian Part No. 198003)

All other chemicals are reagent grade or HPLC grade.

Sample Preparation and Extraction

Liquid/solid extraction is performed using the Varian Sample Preparation Products Hydromatrix (25g) and matrix (25g onion). Two grams of Florisil is added to the homogeneous mixture followed by Accelerated Solvent Extraction (ASE) with ethyl acetate (100 mL, 100 bar, 50 0C). After 100 μL of ndodecane is added to the extract, the solution is evaporated to dryness and the residue is dissolved wi th 25 mL of acetonitrile. The final solution is then spiked with 5 ppb of herbicides.

Results and Discussion

The MS/MS conditions shown above are determined with the Automated MS/MS Breakdown software (also see Varian LC/MS Application Note 11 and 12).

The LC method uses a fast gradient program for a complete analysis in less than ten minutes. Due to the structural similarity of the acidic herbicides, incomplete resolution is observed under faster separation conditions.

The relative selectivity of LC/MS (SIM mode) and LC/MS/MS (MRM mode) are directly compared using spiked matrix samples. For pure standards, the sensitivity in the SIM mode is excellent, but even at the highest spiked concentration of 5 ppb, matrix interferences are strong. In Figure 2, SIM plots for all four herbicides shows extra peaks and baseline instability. For mecoprop, an interfering peak clearly overlaps with the analyte. As with a LC/UV detector, reliable quantitation is not possible with SIM, especially at lower concentrations.

Using the same spiked matrix extract, the increased selectivity of MS/MS is readily apparent. The MRM chromatograms in Figure 3 are interference free. The baseline is clear from any false positive peaks and no cross talk effect is observed when similar product ions are monitored in the same segment time (Table 1 and Figure 3). With the elimination of these matrix interferences, quantitation with high confidence is possible.

The MRM method has excellent linearity for all the herbicides from 0.1 to 5 ppb as shown for dichlorprop in Figure 4. The developed MRM method is also very sensitive with a LOD of 0.1 ppb for all the pesticides under the described instrument conditions.

Conclusion

This 1200L LC/MS/MS method is simple, fast, and hig hly sensitive. The method can quantitatively analyze pesticides at sub-ppb levels and maintain accuracy even with complex matrices. The 1200L LC/MS/MS system is recommended when sensitivity and selectivity are required at very low concentration.


'"/>

Source:


Page: All 1 2 3

Related biology technology :

1. A Positive Selection Assay for Mutation Analysis in Big Blue Animals
2. Epitope-Tagging Vectors for Functional Analysis in Yeast
3. Map and Link Human Genetic Disorders with SSLP Analysis
4. CastAway Precast Gels for Rapid Automated DNA Sequence Analysis
5. Single-cell RT-PCR Analysis of Paramecium Primaurelia with the Eppendorf cMaster RTplusPCR System
6. Structural Analysis of Glycosylated Peptides in Complex Mixtures with Ion Trap MSn
7. Use of Transcriptor Reverse Transcriptase in Microarray Analysis
8. Increased Sensitivity in Microarray Analysis
9. Gene-Expression Analysis of TP, DPD, and TS Using the LightCycler mRNA Quantification KitsPLUS
10. Agilent 2100 Bioanalyzer Automated Analysis System
11. Analysis of Microarray Data
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:1/19/2017)... Md. and GAITHERSBURG, Md. ... (NYSE MKT: PIP) and Altimmune, Inc., a privately-held ... signing of a definitive agreement for the merger ... Altimmune,s current investors include Novartis Venture Fund, HealthCap, ... will be a fully-integrated and diversified immunotherapeutics company ...
(Date:1/19/2017)... Linda, Ca (PRWEB) , ... January 18, 2017 ... ... virtual events for tech innovators, engineers, and scientists from around the world, was ... American News. The awards program is based entirely on merit and decided upon ...
(Date:1/19/2017)... BETHESDA, Md. , Jan. 18, 2017  Northwest ... company developing DCVax® personalized immune therapies for operable and ... Marnix Bosch , Chief Technical Officer of NW Bio, ... Thursday, January 19, 2017, at the Hyatt Regency Hotel ... Dr. Bosch will chair the session entitled "New Therapeutic ...
(Date:1/18/2017)... , January 18, 2017 According to a new market ... Neuroscience, Cytology, Infectious Disease), & End User (Molecular Diagnostic Laboratories, Academic and Research ... to reach USD 739.9 Million by 2021 from USD 557.1 Million in 2016, ... ... MarketsandMarkets Logo ...
Breaking Biology Technology:
(Date:1/6/2017)... LA JOLLA, Calif. , Jan. 6, 2017 ... Phase 1 safety studies in healthy volunteers of ... CM4620, intended to treat acute pancreatitis. ... pancreas, is typically a mild disorder, but can ... to organ failure and sepsis, where extended hospital ...
(Date:1/3/2017)... VEGAS , Jan. 3, 2017 Onitor, ... the introduction of Onitor Track, an innovative biometric data-driven ... men, showcasing this month at the 2017 Consumer Electronics ... In the U.S., the World Health ... more than two-thirds of adults who are overweight or ...
(Date:12/19/2016)... 19 de diciembre de 2016  Mosaic Biomedicals SL anunció hoy ... de MSC-1, un anticuerpo humanizado que se espera comenzar a utilizar ... múltiples sitios previstos a lo largo de Europa y Norteamérica. ... MSC-1 es el primer ... leucemia (LIF), una citoquina pleiotrópica que se sobreexpresa en ciertos tumores ...
Breaking Biology News(10 mins):