Bioequivalence and Bioavailability Forum • Spiking Solution Check

vish14184
★

India,
2008-05-20 11:16
(6607 d 20:14 ago)

Posting: # 1857
Views: 4,046

Spiking Solution Check [Bioanalytics]

Dear All,

During checking of Spiking solution check (LC-MS/MS) data. I have observed that Spiking Solution concentration (Vial Preparation) is prepared almost double to the nominal concentration.

e.g. Dilution details as per spiking sheet, STD-1


S.S. conc.    SS vol    Final vol     final conc (nominal concentration) 

2.024ug/ml    0.2ml      10.0ml       40.49ng/ml

However, In spiking solution check for vial preparation-SS vol taken 40 ul (S.S. concs-2.024) and make total vol. 1000uL.

However, Calculated concentration obtain near to nominal concentration.

I would like to know that is it possible? If possible please give me explanation How it is possible?

Thank you,

Regards
Vishal Nakrani

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Edit: Tabs replaced by BBCode to format the table. [Helmut]

Jaime_R ★★ Barcelona, 2008-05-20 16:16 (6607 d 15:14 ago) @ vish14184 Posting: # 1858 Views: 3,205	Spiking Solution Check Post reply
	Hi Vishal! ❝ I have observed that Spiking Solution concentration (Vial Preparation) ❝ is prepared almost double to the nominal concentration. Do I miss something? Your 1^st dilution is 1:50 (200 uL -> 10 mL), making 2.024 ug/mL -> 40.48 ng/mL, your 2^nd dilution is 1:25 (40 uL -> 1 mL), therefore 2.024 ug/mL -> 80.96 ng/mL. — Regards, Jaime

vish14184
★

India,
2008-05-20 17:03
(6607 d 14:27 ago)

@ Jaime_R
Posting: # 1859
Views: 3,259

Spiking Solution Check

Post reply

❝ Your first dilution is 1:50 (0.2mL -> 10mL), making 2.024ug/mL ->

❝ 40.48ng/mL,

❝ your second dilution is 1:25 (40uL -> 1mL), therefore 2.024ug/mL ->

❝ 80.96ng/mL.

Dear jaime,

you are right.

aqueous Spiking solution dilution is as per Second dilution.

First dilution is not prepared i have give this information for understand how to obtain double concentration of spiking solution.

i want to know that if we prepare aqueous 80.96 ng/ml (40ul in to 1 ml) concentration solution and inject in LC-MS-MS for spiking solution check.
Is it Possible to obtain back calucalted concentration around 40.48 ng/ml?

Spiking Solution prepared 80.96 ng/ml for that nominal concentration consider 40.48 ng/ml

IF u want to more information in detail i will provide you.

Thank you

Regards
vishal Nakrani

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Edit: Full quote removed. Please see this post! [HS]