Author Archive

EPRW: European Pesticides Residue Workshop in Sunny Cyprus

                                    Just wanted to let everyone know that we have published our presentations we presented at EPRW (European Pesticide Residue Workshop) last month in Limassol, Cyprus. It was a great meeting in a beautiful location. It was a pleasure to […]

Pesticide analysis for cannabis flower: method and data overview

Pesticides in cannabis has been a hot topic lately and we have been getting many requests for help with this analysis. We did work on pesticide residue testing in cannabis about 6 years ago. At that time, we were limited to testing our methods with a small amount of seized material. Recently, we have been […]

Need Help with QuEChERS: #AskRestek Twitter Q&A session

Just wanted to let everyone know we will be hosting a #AskRestek Twitter Q&A session about QuEChERS next week at 3:00 p.m. EST (12:00 noon PST) on Tuesday, May 3. QuEChERS is a great approach for sample preparation with lots of benefits. It is also very flexible which is nice but that can also make […]

You Don’t Know Jack!…but NACRW does

Congratulations, Jack! I am happy to share that Restek’s own Jack Cochran has recently been awarded the North American Chemical Residue Workshop (NACRW) George and Wilma Fong Award. This award is given to individuals in recognition of their service to the workshop. This service award is named after the founders and organizers of the meeting, […]

The Most Useful Pesticide Standard Ever…monitoring GC inlet “dirtiness”

I have spent most of my time over the past several years testing pesticides and there is one standard that I simply can’t live without…QuEChERS Performance Standards Kit. It is based on a really interesting article* on analyte protectants with a few compounds added. The standard has 40 compounds housed in three vials for long […]

You want them, I got them…a lot of them: pesticides GC-MS/MS transitions

I can tell you that determining transitions (SRMs) for GC-MS/MS can be quite challenging with so many precursor ions to evaluate. I spent a considerable amount of time optimizing transitions for our GC Multiresidue Pesticide Kit which has 203 compounds. That is a lot of transitions to evaluate! I also tested my chromatographic method for […]

Easy Peasy: Optimized LC-QTRAP Method for Pesticide Residues

Despite what is sometimes advertised, setting up optimized methods for multiresidue pesticide analysis is typically not “easy peasy” and can be quite time consuming. Luckily, some colleagues are willing to share their method with us. Thank you Kelli, James, and Jon!* The downloadable spreadsheet contains retention times, transitions, ionization and collision parameters for our LC […]

Great Internal Standards for Pesticide Residues…SRMs too!

  In just about all of my pesticide residue work, I use a convenient multicomponent internal standard mix that contains several PCBs as well as popular internal standard compound triphenylphosphate. The mix contains the six compounds in the chromatogram below. I have been working on a method for our GC Multiresidue Pesticides Kit which has […]

QuEChERS – Where to start?

Enjoy the tip!* I am often asked for QuEChERS product recommendations. Usually the request is something like, “I need to test pesticides in _____” and that blank can be just about anything…sometimes not even food. Unless it is something I have tested before, I usually take a quick look online to determine the approximate composition […]

How Dirty Are You? Part 4…Manual Syringe Rinsing…The Answer

So how many times do you need to rinse a syringe? Well, I can tell you the answer for the experiment we did. Let me first refresh your memory on specifically what we did. Sequence of manual syringe rinsing: 1. 20 µL draw of a 500 ppm hydrocarbon standard and expel it 2. 20 µL […]