Narong Chamkasem

6 Questions 438 Answers 0 Followers

Questions related from Narong Chamkasem

How to determine accuracy and precision of inter-day and in-traday?

Hi: I am validating a method by spiking 3 levels of one analyte in three different matrices in triplicate in two different days (see attached file). How would I determine the accuracy (average %...

16 February 2018 7,349 0 View

How to extract ethylene thiourea (ETU) and propylene thiourea (PTU) from appled?

I have a tough nut to crack. I spiked a mixed standard (Amitrole, ETU, PTU, Cyromazine, Mepiquat, Chlormequat, and Daminozide into 10 g apple and stored them in a freezer over the weekend and...

23 December 2016 3,756 7 View

Any advice on Paraquat diquat analysis in potato by LC/MS?

I try to quantify paraquat/diquat in potato using LC/MS similar to the attached method but using different LC column. I use standard in solvent with internal standard (IS) to correct for matrix...

03 December 2015 2,113 9 View

Does anyone have experience with the extraction of glyphosate in milk with solvent crash?

I try to extract glyphosate in milk. I spiked glyphosate in milk and immediately shaked with 0.1% formic/Methanol at 1:3 ratio to precipitate protein, centrifuge and dilute 10 time and detect...

30 September 2014 3,321 4 View

The retention time of glyphosate is less than the void volume retention time. What is your opinion on this?

This publication uses a column 150 x 4.6 mm, the void volume of this column is 1.75 mL. At the flow rate of 1.2 mL/min, the non-retain peak should be out at 1.75/1.2 = 1.45 min. However, the...

09 September 2014 9,087 10 View

Suggestion on the method

Simultaneous determination of the quaternary ammonium pestic... With all of the sample preparation step, you still have significant matrix effect and need standard addition or matrix-matched...

01 January 1970 4,281 6 View