Narong Chamkasem

9 Questions 385 Answers 0 Followers

Questions related from Narong Chamkasem

How to get rid of carryover on my HPLC autosampler?

I have an Shimadzu SIL-20A which has a very good specification among autosampler in the market. I am analyzing POEA-15 (polyehtoxylated tallow amine) a non-ionic surfactant on a reversed-phase...

11 November 2016 2,935 32 View

Which LC/MS instrument I should purchase to use it Kazakhstan so I can get good performance and especially service/availablity?

If I need to use LC/MS instrument to screen chemicals in food in Kazakhstan's lab, which brand I should choose in term of price, performance, and particularly service, availability, and ease of...

08 August 2016 1,398 8 View

How to determine phenol in fish samples?

we have fish sample from Vietnam that I need to determine phenol content. Any suggestion? Thanks, Narong

06 June 2016 3,901 3 View

Can anyone help me to extract paraquat/diquat from potato?

I am using the published method to extract paraquat/diquat from potato. I used 10 g sample shake with 1:1 MeOH:0.1 N HCl for 10 min and heat in a water bath at 80 C for 15 min and shake more for...

01 January 2015 9,251 9 View

Do you have any recovery issues with lipophilic pesticides?

With sample:solvent ratio of 1:2 (5 g with 10 mL acetonitrile), you have good overall recovery. I used 0.5 g of oil with 30 mL acetonitrile just to maintain amount of oil at 0.5 g for fear of...

12 December 2014 1,660 9 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 2,647 11 View

Would you please give any suggest of Thiram extraction in sample?

I try to analyzed Thiram as an intact molecule by LC/MS in the vegetable sample. I can get good peak shape of Thiram standard in acetonitrile using a mixed-mode column. The calibration is good...

01 January 1970 830 10 View

What for your compound?

I did a google search and foun lots of methods for detection you can derivatize and do gc you can use a revered-phase with ion-pair with acid. If have to do it, I will try my mixed phase colume...

01 January 1970 724 1 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...

01 January 1970 4,008 5 View