AOAC ERP Fertilizers - March 2019

3/14/2019

AOAC EXPERT REVIEW PANEL FOR FERTILIZERS

UPDATE ON ADDITIONAL VALIDATIONS AND NEXT STEPS FOR THE METHOD 

• Validation Materials/Test Samples • Selection • Homogeneity testing • Method “updates” • Dual/Radial view • Custom stock standards • Nebulizer change

• More high P concentration options • Weight change • Empirical calibration

• Why isn’t this done? !!!

3

AOAC EXPERT REVIEW PANEL FOR FERTILIZERS

• Validation Materials/Test Samples:

• Homogeneity testing performed, but pending calculations

Material

Matrix % P 2

O 5

P 2

O 5

Level

Note MDL

% K 2

O K 2

O Level

Note MDL MDL

1 2 3 4 5 6

Urea

Solid Solid Solid Liquid

0 0 0

0 0 0

0 0 0

0 0 0

Copper Sulfate, anhydrous

Interferent

Lithium Nitrate

MDL LOQ Bias

Interferent

Liquid 0.02‐0.02‐0.02

0.02

Low Low Low Low

0.02

Low Low Low Low

LOQ Bias

4‐2‐3‐2Ca 

Organic

2+

3+

CHECK ROCK 22

Solid Solid Solid Solid Solid

?

Matrix

?

Matrix

7 Magruder 2002‐06 10‐10‐10 8 Magruder 2004‐03 19‐19‐19

10 19 23 24 34 37 40 45 46 46 50 52

Accuracy Accuracy Precision Precision Dissociate Dissociate Ingredient Ingredient Ingredient Ingredient Ingredient Accuracy Bias

10 19 30 24 26

Accuracy Accuracy Precision Precision Precision

Medium Medium Medium Medium Medium Medium

Medium Medium Medium Medium

9

0‐23‐30 TSP blend 6‐24‐24 blend 0‐(29)‐26 Phosphite

10 11

Liquid Liquid Liquid Solid

0 (29)

12 Polyphosphate 10‐34‐0 13 Polyphosphate 11‐37‐0

n/a n/a n/a n/a n/a n/a n/a n/a

n/a n/a n/a n/a n/a n/a n/a n/a Low High High High High High

n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a

14

MAP + S

High High High High High High n/a n/a

15 0‐45‐0 Triple Superphosphate Solid

16 Diammonium Phosphate (1) 17 Diammonium Phosphate (2)

Solid Solid Solid Solid Solid Solid Solid Solid Solid Solid

18 Monoammonium Phosphate Solid

19 20 21 22 23

SGS MAP

0‐0‐2

n/a n/a n/a n/a n/a n/a 0

n/a n/a

2

0‐0‐22 (11Mg, 22S) NIST 193 ‐ KNO 3 Potassium Sulfate

22

Medium

0

MDL n/a

46.60

Accuracy Ingredient Ingredient Ingredient Accuracy

n/a n/a n/a n/a

50 60 62 63

24 Muriate of Potash 0‐0‐60 25 Muriate of Potash 0‐0‐62

n/a n/a n/a

26

Reagent Grade KCl

4

2