Quantify more than 700 pesticides in 10 different food matrices

Feb 18, 2021 | Blogs, Food / Beverage | 0 comments

Read time: 3 minutes

A recent webinar from SCIEX and New Food, presented by Jianru Stahl-Zeng of SCIEX, outlined some of the capabilities of the new SCIEX Triple Quad™ 7500 LC-MS/MS System – QTRAP® Ready. In particular, it highlighted the ability of the SCIEX 7500 System to accurately quantify 700 pesticide residues across 10 different food matrices at ultra-low trace levels. During the webinar, attendees posed various questions. Here, we share the top 5 of these questions, along with their answers.

 

1. How did you set up the OptiFlow® Pro Ion Source for the assay? Is it any different from the Turbo V™ Ion Source? The OptiFlow Pro Ion Source typically requires lower carrier gas (Gas 1) pressure and ion spray voltage than the Turbo V Ion Source. This assay uses 1500 V for the ion spray and Gas 1 at 35.

2. What is the dynamic range of the SCIEX 7500 System? The SCIEX 7500 System offers a linear dynamic range spanning up to 6 orders of magnitude.

3. How are data points related to cycle time and dwell time? How does this affect the peak shape? You will get sufficient data points to ensure your quantification quality when your instrument is fast enough and the cycle time is not too long. A shorter cycle time and dwell time equals more data points. Enough data points are essential for reproducible peak shape. With advanced sMRM algorithm, you are able to run so many compounds with shorter cycle times.

4. How long does it take to switch polarity from positive to negative mode? How does this impact my assay? And what is the dwell time for each multiple reaction monitoring (MRM) transition in the positive and negative modes? The SCIEX 7500 System can switch polarity in as little as 5 ms. In our screening assay, where we strive to get a large number of data points, we used 5 ms. In the quantitative assay, where reproducibility and consistent peak integration are important, we used 15 ms. Given the target cycle time of 350 ms, the longer polarity switching time had minimal impact on the number of points across each peak. Dwell time for each transition is calculated by SCIEX OS Software and depends on factors such as your liquid-chromatography (LC) separation, the number of coeluting peaks and the predefined cycle time. This is the same for both positive and negative modes.

5. Along with signal increase, does the larger orifice also affect noise in the system? With a larger orifice, the background noise will increase for some of the analyte signals as you are sampling more ions from the source stream. However, the analyte-specific signal increases will outpace the background noise and deliver meaningful signal-to-noise gains from the SCIEX 7500 System.

For more information on the capabilities of the SCIEX 7500 System, and to access related content, catch the webinar on demand.

RUO-MKT-18-12793-A

Understanding PFAS and its impact on U.S. drinking water

In recent years, per- and polyfluoroalkyl substances (PFAS), often referred to as “forever chemicals,” have become a growing topic of interest due to their persistence in the environment and potential health risks. These synthetic compounds have been widely used in various industrial applications and consumer products since the 1940s. PFAS can be found in the air, soil, and water, and studies have shown that most people have detectable levels of PFAS in their bloodstream. One of the main exposure pathways for humans is through drinking water, particularly in communities located near industrial sites, military bases, or areas where firefighting foam has been used.

Selecting an LC-MS system for quantitation of pharmaceutical drug development

We understand you are busy, needing to prioritize running instruments, reporting results and managing your laboratory to meet deadlines. We created a solution guide to explain how SCIEX systems fit in the drug development pipeline to save you time evaluating options.

Nitrosamines: Where are we now?

Nitrosamines are a large group of N-nitroso compounds that share a common functional N-N=O group. They are produced by a chemical reaction between a nitrosating agent and a secondary or tertiary amine. Back in 2018, nitrosamines suddenly found themselves in the spotlight when they were unexpectedly detected in medications for high blood pressure. Since then, they have been found in several other prescription medications, including those for heartburn, acid reflux and diabetes, resulting in manufacturers recalling some common medications.

Posted by

Global Technical Leader for Food and Environmental Applications, SCIEX

Tags


0 Comments

Submit a Comment

Wordpress Social Share Plugin powered by Ultimatelysocial