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2C - Vegetation Ash - INAA

The ash material is encapsulated in a polyethylene vial and irradiated with flux wires and an internal standard (1 for 11 samples) at a thermal neutron flux of 7 x 10 12 n cm -2 s -1.  After a 7-day period, to allow Na-24 to decay, the samples are counted on a high purity Ge detector with resolution of better than 1.7 KeV for the 1332 KeV Co-60 photopeak.  Using the flux wires, the decay-corrected activities are compared to a calibration developed from multiple certified international reference materials. The standard present is only a check on accuracy and is not used for calibration purposes. From 10-30% of the samples are rechecked by re-measurement.  For values exceeding the upper limits, assays are recommended.

 

One standard is run for every 11 samples. One blank is analyzed per work order. Duplicates are analyzed when samples are provided.

 

Required Preparation: Code  B3 (ashing of vegetation in dedicated kilns at 475°C for 18-24 hours)

 

Code 2C (Vegetation Ash-INAA) Elements and Detection Limits (ppm)

Element

Detection Limit

Element

Detection Limit

Element

Detection Limit

Element

Detection Limit

Ag

2

Cs

0.5

Mo

2

Sr

300

As

0.5

Eu

0.01

Na

10

Ta

0.5

Au

5 ppb

Fe

0.05%

Nd

5

Tb

0.5

Ba

50

Hf

0.5

Ni

50

Th

0.1

Br

1

Hg

1

Rb

5

U

0.1

Ca

0.2%

Ir

2 ppb

Sb

0.1

W

1

Ce

3

K

0.05%

Sc

0.1

Yb

0.05

Co

1

La

0.1

Se

2

Zn

50

Cr

1

Lu

0.05

Sm

0.1

 

Code 2C Add-On Detection Limit (ppm)

Element

Detection

Limit

B

2

 

Reference :
Hoffman, E.L., 1992. Instrumental Neutron Activation in Geoanalysis. Journal of Geochemical Exploration, volume 44, pp. 297-319.

 


Activation Laboratories Ltd. | 41 Bittern Street, Ancaster, Ontario, L9G 4V5, Canada | TF: +1.888.228.5227
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