13 replies to this topic

[JCSL]

Hi there,

 

I am confused with the terms internal verification, internal calibration and external calibration? What is the difference? Is internal verification same with internal calibration?

 

Thanks .

[Charles.C]

Hi there,

 

I am confused with the terms internal verification, internal calibration and external calibration? What is the difference? Is internal verification same with internal calibration?

 

Thanks .

 

Hi JCSL,

 

Can you provide some context to clarify the terms mentioned, eg source/application of the terms ?

 

Offhand, i have never encountered any of them.

 

Do you mean internal/external standard calibration ?? eg -

 

https://en.wikipedia...ternal_standard

.

Depending on the context, the term "calibration"  has a variety of possible meanings. And so does "verification".

 

PS - from google, "internal verification" can have a specific meaning (new one for me), eg  -

http://www.sqa.org.uk/sqa/74671.html

(unrelated to calibration afai can see)

[GMO]

I could imagine all of these terms being used with respect to weight / balance calibration.

 

So for example, an internal verification may be checking a single pack of known weight.

 

An internal calibration could be using calibrated weights traceable to national standards to check the accuracy of the balance and adjusting it if it is outside tolerance. 

 

An external calibration would be doing the same but either by a third party or by sending the equipment off site.

[QAGB]

I could imagine all of these terms being used with respect to weight / balance calibration.

 

So for example, an internal verification may be checking a single pack of known weight.

 

An internal calibration could be using calibrated weights traceable to national standards to check the accuracy of the balance and adjusting it if it is outside tolerance. 

 

An external calibration would be doing the same but either by a third party or by sending the equipment off site.

 

 

Weight/ balance calibration is usually where I would hear this terms as well. Another option, could also be just generally with laboratory equipment; pH meters, moisture analyzers, viscometers, etc. In those cases all of the definitions GMO has given apply; just not to weights and balances. 

 

In summary, an internal verification is a check using some standard or known quantity to ensure equipment is working within designed normal parameters. An internal calibration is the check or adjustment of an instrument using qualified and *certified* standards to designed normal parameters. An external calibration is the same, just done by an outside source -- as GMO stated.

 

QAGB

[Charles.C]

Only one comment - Google had zero knowledge of the specific terms internal/external calibration.

 

Specific to the OP perhaps ?

[Charles.C]

amendment

 

I found "one" -

 

US Pharmacopoeia

 

 Reliable quantitative results are obtained by external calibration if automatic
injectors or autosamplers are used. This method involves direct comparison of the
peak responses obtained by separately chromatographing the test and reference
standard solutions. If syringe injection, which is irreproducible at the high
pressures involved, must be used, better quantitative results are obtained by the
internal calibration procedure where a known amount of a noninterfering
compound, the internal standard, is added to the test and reference standard
solutions, and the ratios of peak responses of drug and internal standard are
compared.

 

 

 WSC7-T05-Kalambet.pdf   500.9KB   141 downloads

 

I think this is similar to the interpretation in my previous Post.

 

Context is maybe everything.

[QAGB]

amendment

 

I found "one" -

 

WSC7-T05-Kalambet.pdf

 

I think this is similar to the interpretation in my previous Post.

 

Context is maybe everything.

Hi Charles,

 

That item you posted looks to be related to liquid chromatography. In my previous employment, that was what was something we used in our analyses. An external calibrator was a standard that was run side by side with your actual product sample for analysis and comparison. The external calibrator is treated as its own sample. It could be used to determine product quantities from a known amount (the calibrator), and it also could be used to determine if the product actually contained the analyte desired. 

 

An internal calibrator was used for products where there might be some evaporation of product, and as such the internal calibrator was used to determine the quantities of product in consideration of evaporation. The internal calibrator is placed inside the actual sample. The internal calibrator was of a known amount, and you use the known amount to determine how much evaporation happened during testing; thus being able to determine analyte concentration. 

 

I just wouldn't have expected that to be related necessarily to this sort of forum.

 

QAGB

[Charles.C]

Hi QAGB,

 

Actually, afaik, it is just one example of a general analytical technique.

 

But whether it relates to the OP, yr guess is as good as mine ! Maybe better.

[Scampi]

Alternatively:

 

Verification...is a probe thermometer reading a temperature that is within an acceptable range (e.g. 99.9 and not 100F) by testing it against a known temperature 

 

Internal Calibration.....following the instructions that came with an instrument to calibrate it yourself (ice slurry, boiling water)

 

External Calibration....sending an instrument to the correct vendor to have them calibrate it OR having a technician come to your facility to calibrate a wall mounted thermometre

[Scampi]

We verify our instruments monthly and have a schedule for outside vendors to calibrate yearly and/or following manufactures instructions for in house calibration

[Scampi]

C.1.2.2

The establishment has and implements a documented Equipment Calibration Program

which includes but is not limited to:

• A list of equipment monitoring and controlling devices that may impact on food

safety requiring regular calibration;

• A calibration schedule or frequency of calibration activities;

• The calibration procedures to perform for each calibration task;

• Records to be kept to demonstrate that the calibration tasks have been

completed.

Food Safety Enhancement Program

________________________________________________________________________

2014-07-01 FSEP Manual – Section 3 page 25

Note: The calibration procedures are based on the equipment manufacturer’s manual or

equivalent.

[Charles.C]

Hopefully the OP will take his "Pick". And explain it.

[Mesha]

Hi there,

 

I am confused with the terms internal verification, internal calibration and external calibration? What is the difference? Is internal verification same with internal calibration?

 

Thanks .

Broadly -

 

Internal Verification - Verification of your measuring device against calibrated standards (those can be secondary standards as well). Weighing balances, pH meter, Ovens etc to ensure "OK" to use on daily basis. Also referred to as "system suitability test" especially in chromatography.

 

Internal Calibration - Calibration of your measuring device against calibrated standards ( Secondary standards allowed). This is interrelated to Internal verification as it depends a lot on the instruments/equipment etc. For example Verification for a weighing balance may require verification against the weight range for which it is actually put to use whereas calibration will require calibrating the entire range of the balance as claimed by the manufacturer of the balance in the documents.

 

For chromatography instrument internal calibrations is a long procedure and I don't remember getting an external calibration done which was "OK" to ISO 17025 assessors .

 

External calibration - Calibration of your secondary standards against traceable primary national standards AND/OR calibration of your measuring device against the same by an external approved agency.

 

Regards,

Meena

[Charles.C]

Hi JCSL,

Any comments ?