Stability Constants (log K1) of Various Metal Chelates
from
Chapter 6 - Sequestrants in Foods, by Thomas E. Furia, in CRC Handbook of Food Additives,
2nd ed. 1972 as revised by cited authors (where data shows a letter corresponding to citation at bottom of table)

latest revision October 26, 2006
NOTE: THIS FILE IS UPDATED UPON FINDING USEFUL FOOD CHEMISTRY DATA

webmaster - George Eby

What are " Stability Constants"

The A. E. Martell's NIST Critically Selected Stability Constants of Metal Complexes is the Bible for stability data for metal and ligand reactions. However, it is an expensive and vast document. Stability constants for very strong chelators is found on the Stanford MAXCHELATOR page. A general search for A.E. Martell's critical stability constants is here. Unfortunately, Dr. Martell died in 2003.

Metal (to right)
Ligand (below)

   Al(III)

Ba

Ca

Co(II)

Cu

Fe(II)

Fe(III)

Hg

Mg

Mn

Ni

Sr

Zn

Acetic acid

 

0.39

0.53

2.24

 

 

 

3.7d

0.51

 

0.74

0.43

1.03

Adenine

 

 

 

 

 

 

 

 

 

 

 

 

 

Adipic acid

 

1.92

2.19

 

3.35

 

 

 

 

 

 

 

 

ADP

 

2.36

2.82

3.68

5.90

 

 

 

3.11

3.54

4.50

2.50

4.28

Alanine

 

0.80

1.24

4.82

8.18

 

 

 

 

3.24

5.96

0.73

5.16

b-Alanine

 

 

 

 

7.13

 

 

 

 

 

4.63

 

4

Albumin

 

 

2.20

 

 

 

 

 

 

 

 

 

 

Arginine

 

 

 

 

 

3.20

 

 

 

2.0

 

 

 

Ascorbic acid

 

 

0.19

 

 

 

 

 

 

 

 

0.35

 

Asparagine

 

 

0

 

 

 

 

 

 

 

 

0.43

 

Aspartic acid

 

1.14

1.16

5.90

8.57

 

 

 

2.43

3.74

7.12

1.48

5.84 2.90a

ATP

 9.8

3.29

3.60

4.62

6.13

 

 

 

4.0

3.98

5.02

3.03

4.25

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Benzoic acid

 

 

 

 

1.6

 

 

 

 

 

0.9

 

0.9

n-Butyric acid

 

0.31

0.51

 

2.14

 

 

 

0.53

 

 

0.36

1.00

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Casein

 

 

2.23

 

 

 

 

 

 

 

 

 

 

Citraconic acid

 

 

1.3

 

 

 

 

 

 

 

 

1.3

 

Citric acid

 11.7e

2.3

3.5

4.4

6.1

3.2

11.85

10.9d

2.8

3.2

4.8

2.8

4.5

Cysteine

 

 

 

9.3

19.2

6.2

 

14.4d

< 4

4.1

10.4

 

9.8

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Dehydracetic acid

 

 

 

 

5.6

 

 

 

 

 

4.1

 

 

Desferri-ferrichrysin

 

 

 

 

 

 

29.9

 

 

 

 

 

 

Desferri-ferrichrome

 

 

 

 

 

 

29.0

 

 

 

 

 

 

Desferri-ferrioxamin E

 

 

 

11.8

13.7

 

32.5

 

 

 

12.2

 

12.0

3,4-Dihydroxybenzoic acid

 

 

3.71

7.96

12.79

 

 

 

5.67

7.22

8.27

 

8.91

Dimethylglyoxime

 

 

 

 

11.94

 

 

 

 

 

14.6

 

7.7

O,O-Dimethylpurpurogallin

 

 

4.5

6.6

9.2

 

 

 

4.9

 

6.7

 

6.8

 DNA

 <5.6e

 

 

 

 

 

 

 

 

 

 

 

 

Metal (to right)
Ligand (below)

   Al(III)

Ba

Ca

Co(II)

Cu

Fe(II)

Fe(III)

Hg

Mg

Mn

Ni

Sr

Zn

EDTA

16.13

7.78

10.70

16.21

18.8

14.3

25.7

21.5d

8.69

13.56

18.56

8.63

16.5

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Formic acid

 

0.60

0.80

 

1.98

 

3.1

 

 

 

 

0.66

0.60

Fumaric acid

 

1.59

2.00

 

2.51

 

 

 

 

0.99

 

0.54

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Globulin

 

 

2.32

 

 

 

 

 

 

 

 

 

 

Gluconic acid

 

0.95

1.21

 

18.29

 

 

 

0.70

 

 

1.00

1.70

Glutamic acid

 

1.28

1.43

5.06

7.85

4.6

 

 

1.9

3.3

5.9

1.37

5.45

Glutaric acid

 

2.04

1.06

 

2.4

 

 

 

1.08

 

 

0.6

1.60

Glyceric acid

 

0.80b

1.18b

 

 

 

 

 

0.86b

 

 

0.89b

1.80b

Glycine

 

0.77

1.43

5.23

8.22

4.3

10.0

10.3d

3.45

3.2

6.1

0.91

5.16

Glycolic acid

 

0.66

1.11

1.60

2.81

 

4.7

 

0.92b

 

 

0.80b

1.92b

Glycylglycine

 

 

1.24

3.00

6.7

2.62

9.1

 

1.34

2.19

4.18

 

3.91

Glycylsarcosine

 

 

 

3.91

6.50

 

 

 

 

2.29

4.44

 

 

Guanosine

 

 

 

3.2

6

4.3

 

 

3.0

 

3.8

 

4.6

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Histamine

 

 

 

5.16

9.55

9.60

3.72

 

 

 

6.88

 

5.96

Histidine

 

 

 

7.30

10.60

5.89

4.00

 

 

3.58

8.69

 

6.63

b-Hydroxybutyric

 

0.43b

0.60b

 

 

 

 

 

0.60b

 

 

0.47b

1.06b

3-Hydroxyflavone

 

 

 

9.91

13.20

 

 

 

 

 

 

 

9.70

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Inosine

 

 

 

2.6

5

3

 

 

 

 

3.3

 

 

Inosine triphosphate

 

 

3.76

4.74

 

 

 

 

4.04

4.57

 

 

 

Iron-free ferrichrome

 

 

 

 

 

 

24.6

 

 

 

 

 

 

Isovaleric acid

 

 

0.20

 

2.08

 

 

 

 

 

 

 

 

Itaconic acid

 

 

1.20

 

2.8

 

 

 

 

 

1.8

0.96

1.9

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Kojic acid

7.7

 

2.5

7.11

6.6

 

9.2

 

3.0

 

7.4

 

4.9

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Lactic acid

 

0.55

1.07

1.89

3.02

 

6.4

 

0.93

1.19

2.21

0.70

1.86

Leucine

 

 

 

4.49

7.0

3.42

9.9

 

 

2.15

5.58

 

4.92

Lysine

 

 

 

 

 

 

4.5

 

 

2.18

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Maleic acid

 

2.26

2.43

 

3.90

 

 

 

 

1.68

2.0

1.1

2.0

Malic acid

 

1.30

1.80

 

3.4

 

 

 

1.55

2.24

 

1.45

2.80

Methionine

 

 

 

 

 

3.24

9.1

 

 

 

5.77

 

4.38

Methylsalicylate

 

 

 

 

5.90

 

9.77

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

NTA

>10

4.82

6.41

10.6

12.68

8.84

15.87

 

5.41

7.44

11.26

4.98

10.45

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Metal (to right)
Ligand (below)

   Al(III)

Ba

Ca

Co(II)

Cu

Fe(II)

Fe(III)

Hg

Mg

Mn

Ni

Sr

Zn

Orotic acid

 

 

 

6.39c

 

 

 

 

 

 

6.82c

 

6.42c

Ornithine

 

 

 

4.02

6.90

3.09

8.7

 

 

<2

4.85

 

4.10

Oxalic acid

7.26

2.31

3.0

4.7

6.3

>4.7

9.4

 

2.55

3.9

5.16

2.54

4.9

 

 

 

 

 

 

 

 

 

 

 

 

 

 

b-Phenylalanine

 

 

 

 

7.74

3.26

8.9

 

 

 

 

 

 

Pimelic acid

 

 

 

 

 

 

 

 

 

1.08

 

 

 

Pivalic acid

 

 

0.55