NMR titrationHCOOH; CH3COOH; NaNO2

HCOOH1) 1.0 μL H2SO4 50 μL H2

18O

18

18

18

18

2) 40.5 μL DMF570 μL D2O

18

18

18

18

40 μL 1.5M

3) 6 μL 50% NaOH per aliquot during titration

unlabeled Monolabeled dilabeled

HCOOH (fully protonated) and DMF

NB1p20formic1_C_part-1.jdf

165.9 165.8 165.7 165.6 165.5 165.4 165.3 165.2 165.1 165.0 164.9 164.8 164.7 164.6Chemical Shift (ppm)

unlabeled

dilabeled

monolabeled

B1P2O-a #284-310 RT: 1.43-1.56 AV: 27 SB: 13 1.18-1.24 NL: 3.21E6T: - c Full ms [ 30.00-80.00]

38 40 42 44 46 48 50 52 54 56 58m/z

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

Rel

ativ

e A

bund

ance

47.12

45.11

49.12

46.28 48.2044.34 58.3657.1950.1042.02 43.2240.17

Formic Acid.esp

6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0 -0.5Chemical Shift (ppm)

Standardization: credit to Katie

All acid (0% reacted)

Predicted 50%-reacted point

All formate (100% reacted with NaOH)

DMF

Many thanks to Katie for standardization(δun

0-δun)(δmono-δmono-)= (δun-δun-)(δmono0-δmono)

calibration

0 1 2 3 4 5 6 7 80

1

2

3

4

5

6

7

8

f(x) = 1.0134289299868 x − 0.000509406394531009R² = 0.999999912992084

un/mono16O16O/16O18O

(δun-δun-)(δmono0-δmono)

(δun

0-δu

n)(δ

mon

o-δm

ono-

)

• δ0:shift of acid prior to adding base

• δ-:shift of anion when acid-base rxn is complete

• Other variables dependent on extent of ionization

Mono/di unnecessary? For mono/di: (δmono

0-δmono)(δdi-δdi-)= (δmono-δmono-)(δdi0-δdi)

un/mono VS mono/di

0 1 2 3 4 5 6 7 80

1

2

3

4

5

6

7

8

f(x) = 1.0134289299868 x − 0.000509406394531009R² = 0.999999912992084

un/mono16O16O/16O18O

(δun-δun-)(δmono0-δmono)

(δun

0-δu

n)(δ

mon

o-δm

ono-

)

0 1 2 3 4 5 6 7 80

1

2

3

4

5

6

7

8

f(x) = 1.0136595412 x − 0.0014119207R² = 0.999999811668334

mono/di16O18O/18O18O

(δm

ono0

-δm

ono)

(δdi

-δdi

-)

(δmono-δmono-)(δdi0-δdi)

(δun0-δun)(δdi-δdi-) =(δun-δun-)(δdi

0-δdi)

16O16O/18O18O (un/di)

0 1 2 3 4 5 6 7 80

1

2

3

4

5

6

7

8

f(x) = 1.0272702612 x − 0.0019261323R² = 0.999999743202866

un/di16O16O/18O18O

(δun-δun-)(δdi0-δdi)

(δun

0-δu

n)(δ

di-δ

di-)

Ka ratio:Un/mono/di = 1.0273/1.0137/1

18

18 18

18

Acetic acid (fully protonated)

Inez_NB1p11_Sample2_13C-4.jdf

176.55 176.50 176.45 176.40 176.35 176.30 176.25 176.20 176.15 176.10Chemical Shift (ppm)

Significant increase in height after more unlabeled acetic acid is added

18

18

CH3COOH and DMF credit to KatieAcetic Acid.esp

16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0Chemical Shift (ppm)

Calibration

Many thanks to Katie for standardization

0 1 2 3 4 5 60

1

2

3

4

5

6

7

f(x) = 1.01250562256214 x + 0.000137612538945398R² = 0.999999683533146

UN/MONO

0 1 2 3 4 5 601234567

f(x) = 1.01167825599676 x + 0.00568749995565909R² = 0.999993388828339

MONO/DI

0 1 2 3 4 5 601234567

f(x) = 1.02441687216787 x + 0.00538982102030294R² = 0.999993059171215

UN/DI

Kaun:Kamono:Kadi:

CH3COOH: 1.0244:1.0117:1

HCOOH: 1.0273:1.0137:1

Blp22-a #356-383 RT: 2.01-2.16 AV: 28 SB: 41 1.48-1.71 NL: 3.75E5T: - c Full ms [ 30.00-80.00]

30 35 40 45 50 55 60 65 70 75 80m/z

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

Rel

ativ

e A

bund

ance

62.18

46.16

47.2036.68

Attempted HNO2 synthesis

[M1-H]-

[M2-H]-

BlP22ESI Negative Ion Mode

HNO2

HNO3

Na15NO2 SPECTRA

181818

18

1818