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Questions related from chee ping Tan
When weighing powder substances, static tend to cause unstable reading on an analytical balance, and most annoyingly, causing sample to stuck and disperse around the mouth of test tube. How do...
02 February 2020 1,981 2 View
We used the one step method in the lab to obtain FAME for our GC analysis. Many time we see varying degrees of evaporation of solvent (BF3 and internal standard) from our test tube during the 1...
02 February 2020 1,795 3 View
I'm been running Agilent OPA amino acids method but recently my column loss resolution for some of the peaks and will not resolved to baseline. After some discussion with others people in the...
10 October 2019 5,906 4 View
Hi all, I'm currently running amino acids analysis on an Agilent 1200 HPLC system with DAD ( G1315C). I noticed that I've problem reproducing the intensity of my amino acids standard from...
05 May 2019 8,638 4 View
Hi, I'm trying to make my own borate buffer as per the specification in the picture attached. Concentration of 0.4 N, and a pH value of 10.2. I found a lot of different recipe online and I came...
04 April 2019 5,427 4 View
Hi, I ran analysis on the concentration of Fatty Acids Methyl Ester (FAME) of freeze-dried fish sample using Shimadzu GC2010Plus and its companion software GC Solution. I first plotted a 4...
02 February 2019 858 4 View
Hi, I'm doing amino acids of animals feed. I used Jajic et al. (2013) 's methods for the acid hydrolysis. Briefly, I will mix 0.5 gram of samples with 7 ml of 6 molars HCl-phenol solution, flush...
09 September 2018 6,544 4 View
Hi, I need to analyze amount of cysteine spray-coated on animal feed. I read the AOAC (2000) which briefly stated that: (1) Mix 100 mg feed with 5 ml performic acid and oxidized on ice for 16...
08 August 2018 8,795 5 View
This question is based on the paper by Ogwu & Cohen, 1998. A Simple Colorimetric Method for the Simultaneous Determinat... It was mentioned that a 1.33 mM of cysteine stock solution was prepared...
06 June 2018 1,765 5 View
Hi, I wanted to study cysteine level in animals feed, however, HPLC equipment is not available here. I found this colorimetric method (link at the end of the question) online, but it was...
04 April 2018 8,034 10 View
I'm uncertain as to which compound (NH3-N/NH4-N) does the indophenol blue-hypochlorite method detect? I want to detect ammonia (NH3) in freshwater sample. In addition, when making the standard...
03 March 2018 7,936 3 View
I have some sediment samples from a wetland that I want to analyze for its heavy metal contents using ICP-OES. I intend to perform a partial digestion using microwave assisted digestion method...
10 October 2017 414 6 View
I want to prepare some solution from powder in the range of 1 ml to 50 ml accurately. I understand that the best practices is perhaps by using a calibrated volumetric flask, however, the smallest...
09 September 2017 932 8 View
We already know that methylmercury in water bioaccumulated in the fish bodies through their diet. But does anyone know any evidence of the negative effects of such prolonged low/high-dose mercury...
01 January 2017 1,050 3 View
As with the standard procedures of determining level of nitrite/nitrate in phytoplankton culture medium before and after experiment, I wish also to determine the level of either vitamin B1 or...
03 March 2016 1,673 1 View
I tested 1 or 2 drops of diluted acidic Lugol's iodine (1 drop in 10 ml seawater) and 0.5 % formalin solution on 500 ul of Akashiwo sanguinea on slides. The cells sometime fixed, sometime not....
03 March 2016 8,436 4 View
I'm needing this paper for my reference, but I did not have access for it. Anyone kind enough to provide me a source or share it here? Growth interactions between marine dinoflagellates in...
01 January 2016 9,500 3 View
I heard this saying sometime ago, but I wasn't completely sure about it. Is that any research/info that support this saying or you all have a different opinion about this?
09 September 2015 4,784 2 View
