What cause peak of l-lysine HCl to appear broad and how can i treat it?

I have a problem with l-lysine HCl peak in sample and standard as it appear with shoulder or broad.

04 May 2018 424 0 View

Can any one help me with an hplc UV method for determination of D-Sorbitol?

I am looking for a method to determine D-Sorbitol using hplc UV detector.any one can help

04 May 2018 8,947 7 View

What cause the sample and standard Peak to have a negative absorbance?

I have a problem in hplc analysis of L-cystine analysis that the peak of both sample and standard have negative absorbance. This the first trial . -UV detector at 500nm. -Mobile phase phosphate...

11 December 2017 8,007 2 View

In dissolution test for tablets, What kind of filters used to filter samples contain indigo carmine aluminum lake (E132) as colorant?

In dissolution test for Abilify 5mg (aripiprazole) Results show high results about 110%, while maximum result should not exceed 104%(max. result in content uniformity test). This problem does not...

07 August 2017 7,455 2 View

What is meant by HPLC grade water?

31 December 2016 2,598 4 View

What cause shifting of retention time of a peak forward?

1- I have problem in shifting of retention time of a peak : During analysis of rebamipide, the peak of rebamipide shift forward. for example(Std at 20.0 and sample at 20.5), and as the sample set...

10 November 2016 1,350 10 View

Why does the peak of one substance disappear when injecting a mix of two, but when I inject each substance alone separately, they both give peaks ?

11 December 2014 9,859 13 View

How can I determine the shelf life (expiry date) of prepared volumetric solutions?

When I prepare a volumetric standard solution, I want to determine its expiry date by taking in consideration that it is not mentioned in any reference. And if possible I need a protocol for it.

03 April 2014 6,649 4 View

How to restore my column performance?

31 December 2013 9,085 1 View

What is the official method for analysis of free amino acids by HPLC(WATERS)?

I need to know if this method is the official for analysis or not?

09 October 2013 6,819 5 View

What is the most Operating System (OS) which can be INSTALL on Tiny hard devices like Raspberry Pi (RPi) hardware ?

I'm targeting to deploy a mesh network and manually configure MANET routing protocols. I'm preparing scenarios, architectures, and hard devices needed to do that. Are there some step-by-step...

03 March 2021 1,931 5 View

Looking for Materials with high thermal expansion coefficient and high temperature resistance?

03 March 2021 8,272 1 View

Can we classify HV and LV lines based on line length?

I have dataset which shows the length of power lines. I need to classify the lines based on the line length. Is there a rule to classify the High voltage (HV) and low voltage (LV) lines based on...

03 March 2021 4,116 4 View

Buffer Exchange using column packed with sephadex G-25 effect on protein concentration?

Hello, If i am doing a buffer exchange for an antibody of 1mg/mL, does the elution lose protein in the process of buffer exchange? For example, if i flow through 500 uL of 1mg/mL sample, and...

03 March 2021 6,299 3 View

How two melting peaks in DSC of polypropylene can be merged into one crystallization peak?

The figure shows DSC cooling (blue) and 2nd heating (green) curves (step: 10 K/min) for a commercial sample supplied as Atactic Polypropylene (APP). The heating curve illustrates two major...

03 March 2021 5,857 3 View

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03 March 2021 5,360 2 View

Is there a classification scheme for rock cavities or caverns with respect to their size and shape?

The range of forms and sizes of cavities in rock is very big. Is there a classification scheme for rock cavities regarding their size and shape?

02 March 2021 4,511 3 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

Is There Any Feasible Method To Test Fluorescent Compounds Other Than Fluorescence Spectrometers ??

Is There Any Feasible Method To Test The Efficiency Of Fluorescent Compounds Other Than UV Spectrometers ? Suggestions Would Be Appreciated !

02 March 2021 5,785 3 View

Why almost every element would be metallized in sufficiently high pressure and low temperature?

(This statement is from wikipedia, BTW). What is so special about metallic bond that is limiting high-P low-T state of a matter (as long as individual atoms exist, not white dwarf of neutron star...

02 March 2021 3,309 2 View