What are the main problems associated with measuring testosterone?

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Is anyone aware of studies or work that has been done on looking at using an Androstenedione based free androgen index?

In our institution, testosterone and androstenedione are measured simultaneously using LC-MS/MS and I have come across patients with clinical signs of androgen excess who have normal testosterone...

03 April 2015 7,128 2 View

Which type of compound does lamda max of 218 indicate in a uv-vis spectrum of a partially purified compound through column and TLC?

A crude extract of fungal culture using EtOH was subjected to column and TLC and partially purified compound was obtained. UV vis spectrum of the compound/s has max absorbance at 218nm. The...

11 August 2024 9,801 2 View

Can you connect an HPLC to a Mass Spec only at a certain time point?

Can anyone explain this method? Especially the last statement where it says only at 1.5 to 2.5mins was the MS/MS connected to the UPLC. How is that possible, is it a feature in this specific...

11 August 2024 8,141 3 View

GC-MS retention index prediticon?

Hello experts, Does anyone know any free software about retention index prediction ?

08 August 2024 7,403 2 View

Can I use a HisTRAP column for affinity chromatography?

I'm working on selecting antibodies against a recombinant protein that has a His-tag. My idea is to first bind the recombinant protein to a HisTRAP column and then use this column for an affinity...

07 August 2024 505 3 View

Why is electronic energy 0.000 for liquid crystal compounds and is invariable with temperature in Guassian 09 software?

Are there any suggestions or insights you can provide to help address this problem

06 August 2024 1,443 2 View

Why is TLC not a form of partition chromatography?

Why is TLC not a form of partition chromatography and paper chromatography not a form of absorption chromatography?

03 August 2024 7,035 3 View

Is there any Indian Company or Startups, from any universiy or IITS, which manufacture Gas Chromatography instrument , i want to make a custOmized G?

or we can collaborate

01 August 2024 6,705 2 View

Is there a good freeware software for photodocumentation of TLC?

I need something like Camag's VisionCat software for photodocumentation of TLCs. Could you recommend something?

31 July 2024 8,415 1 View

How to improve peaks separation in HPLC?

Hi everyone, I'd like to better separate two close peaks coming from a bioconversion sample, I'm currently using a C18 KromaPhase 4,6mm Ø.I. SCHARLAU, particle size (µm): 10, pore size (Å): 100,...

30 July 2024 435 3 View

Gas chromatography RT detection?

I am working on algal extract to which gas chromatography (Not GC-MS) spectrum I want to discover. My question is can we identify specific compounds using retention time if I compared the RT with...

29 July 2024 8,034 4 View

Berthold Lausecker

to find the right control matrix

Mohammad Imteyaz Ahmad

Utility, Limitations, and Pitfalls in Measuring Testosterone: An Endocrine Society, Positional Statement.

Comparison of measurement of Testosterone by various methods advantages and disadvantages are illustrated.

http://press.endocrine.org/doi/pdf/10.1210/jc.2006-1864

I was referring to LC-MS/MS because it is known that for ELISAs the result depends on the manufacturer