What is the cell used in volumetric karl fischer titrimetry?

Galvanic Cell or electrolytic cell ? What is the detection technique?

08 September 2012 4,148 2 View

How to prepare and increase yield for acetal synthesis?

I am mixing some chemicals along with propylene glycol with some aldehydes, in some instances there is a formation of acetal but other times not. Does anybody know the thermodynamics & kinetics...

07 August 2012 5,833 2 View

Which is the precise ionization and %area is close to absolute % between MS ionization (GCMS) and FID ionization (GCFID)? Why?

Are the % area of TIC of GCMS and FID comparable? if not why? What is detector linearity? i worked with absolute % (Pharma) of sample composition and also % area composition (in CRO, Synthetic...

09 October 2011 7,638 3 View

How to prepare sample & analyze a volatile content in beverages?

I need to compare two products of same brand by GC / GCMS, i have tried to extract the volatile part of the aqueous beverage by using CH2Cl2, pentane:diethyl ether; but the volatile are very less....

09 October 2011 2,067 6 View

Any body using super critical fluid extraction for analytical sample preparation?

Please tell me the Make/Model of super critical fluid extraction apparatus which can be used for analytical sample preparation. Thanks

08 September 2011 1,232 1 View

What are retention indices in GC, GCMS?

What are retention indices in GC, GCMS?

08 September 2011 3,436 11 View

No title

It is having GPIB Communication; old data acquisition software-HP Chemsation. data analysis is not so good. Sensitivity of the instrument is in question. How could I utilize the instrument...

08 September 2011 1,243 1 View

Anybody using "Y" Splitter for GCMS?

I am using 'Y' splitter for our GCMS, it connected tat column outlet and one part is going to MS and another is going to FID; i have a sensitivity problem in FID and RT differences ( TIC-MS is...

08 September 2011 4,600 7 View

Anybody knows about automated volatile oil determination methods?

We have a classical method of analysis to determine volatile oil in the natural products. It is time consuming- taking 4 hours. How can I improve the tech? Many thanks

08 September 2011 1,734 2 View

No title

08 September 2011 2,452 2 View

Waters 2707 HPLC autosampler problem?

I am using a 2707 waters HPLC device. When I try to inject a sample, it says missing plate or rack. I changed the needle and calibrated its position but I still get the same problem. I even get...

02 March 2021 1,408 1 View

How optimize the Size Exclusion Chromatography?

Hello! I'll do a size exclusion chromatography, but I only have an open column, and I'll perform the peptide extraction from yeast, using buffer lysis (sodium phosphate 50 mM/NaCl 30 mM/DNAse and...

01 March 2021 2,215 2 View

Precipitate after adding laemmli buffer to protein solution containing Potassium Acetate?

Hi, I am running a size exclusion chromatography experiment with a buffer containing Potassium Acetate as a salt. I analyse these fractions through SDS-PAGE. After boiling my SEC fractions in...

01 March 2021 2,622 3 View

Any research papers for extraction of nutrient deprivation on macroalgae? Analysed by HPLC-UV and GC/MS. Possibly from macroalgae genus Rhizoclonium?

I am doing my thesis on the nutrient deprivation on the macroalgae Rhizoclonium sp. I will be analysing the levels over a period of roughly 5 days by HPLC-UV and GC/MS. I will be using seawater as...

28 February 2021 6,477 1 View

Do you kow of any database containing data on retention time, log P and polarizability for a large number of molecules?

Hi, I am a chemistry undergraduate doing my dissertation project on HPLC. In my project, I need to predict the HPLC retention time of 20 aromatic molecules, the calibration set. To do this I will...

24 February 2021 2,602 1 View

Any easy method of analyzing vitamin D in foods by HPLC?

Looking for method of extracting and analyzing vitamin D in foods by HPLC

24 February 2021 7,524 7 View

What HPLC Marker(s) should be used to detect anthocyanins in a sample?

What HPLC Marker(s) or standard is used to detect and quantify anthocyanins such as Delphinidin, Cyanidin in a given sample of plant extract?

23 February 2021 1,832 4 View

HPLC baseline failure (ACN/Water)?

My baseline increases without any explanation, it is only fixed by changing the solution B, will it be the column? Reagents? Bomb? Detector? Solution A: H3PO4 0.01% IN WATER Solution B: H3PO4...

21 February 2021 5,656 3 View

Which vial septa the right one to be used for HPLC?

This is the unanswered question stored very long in my mind and till now I could not find a right answer. Google search educated me that the red surface is the PTFE material compatible to wider...

21 February 2021 546 3 View

What is the stability of 2 3-dihydroxyquinoxaline in acidic water?

I'm developing a UHPLC assay, and the fluorescent product is 2,3-dihydroxyquinoxaline. The reaction to produce this requires hydrochloric acid (about 1.2 M). Will storage in this acidic...

20 February 2021 5,820 4 View