# Hello Scientists, can someone tell me how the ICP Expert II adjusts the intensities of the standard and sample with an internal standard ratio as the method has defined the intensity corrected formula? Also once the internal standard was set up, the intens

The method is to quantify Zn and Ti using Y as an internal standard. Calculate the corrected average intensity. See below. Is the same formula that ICP Expert II uses? have the highlighted intensities been corrected?

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• Hello Tina,

I understand that adding the internal standard to the standard and sample simultaneously is to correct any changes that may affect the intensities of sample and standard. In ICP-OES we set up the ratio of internal standard in blank to 1:00. See below:

The ratio from result table shown is by this formula:

Ratio = Iis (analyte)/ Iis (blank)

When the ratio>1, the intensity of internal standard in sample/ standard is higher than that in blank, the intensity of sample/standard should be adjusted lower

When the ratio<1, the intensity of internal standard in sample/ standard is lower than that in blank, the intensity of sample/ standard should be adjusted higher.

Based on this principle, the formula for the adjustment should be:

Corrected intensity of analyte = intensity of analyte / ratio

It matches our method.

However, as per your email, the software uses the formula :

Ratio = Iis (blank)/ Iis (analyte)

But adjustment is by: corrected concentration = C (analyte) * ratio. The ratio will be different from the above result table that we obtained, but the corrected intensity will be the same as above.

Anyway, the key point is how the software adjusts the readings. If the same principle is followed, there is no impact on our results.

Thank you again,

Best Regards,
Lily Zhong
Health & Nutrition
Health Science - Manager, Document Reviewer
Markham, ON, L3R 9T9

Phone:   +1 905-305-0998

E-mail:    yanping.zhong@sgs.com

• Hello Tina,

I understand that adding the internal standard to the standard and sample simultaneously is to correct any changes that may affect the intensities of sample and standard. In ICP-OES we set up the ratio of internal standard in blank to 1:00. See below:

The ratio from result table shown is by this formula:

Ratio = Iis (analyte)/ Iis (blank)

When the ratio>1, the intensity of internal standard in sample/ standard is higher than that in blank, the intensity of sample/standard should be adjusted lower

When the ratio<1, the intensity of internal standard in sample/ standard is lower than that in blank, the intensity of sample/ standard should be adjusted higher.

Based on this principle, the formula for the adjustment should be:

Corrected intensity of analyte = intensity of analyte / ratio

It matches our method.

However, as per your email, the software uses the formula :

Ratio = Iis (blank)/ Iis (analyte)

But adjustment is by: corrected concentration = C (analyte) * ratio. The ratio will be different from the above result table that we obtained, but the corrected intensity will be the same as above.

Anyway, the key point is how the software adjusts the readings. If the same principle is followed, there is no impact on our results.

Thank you again,

Best Regards,
Lily Zhong
Health & Nutrition
Health Science - Manager, Document Reviewer