OECD Guideline for the Testing of Chemicals, 112

Dissociation Constants in Water

AUTHORS:

Raymond L. Van Hoven, Ph.D.

Frank J. Lezotte, B.S.

Willard B. Nixon, Ph.D.

STUDY INITIATION DATE: September 8, 2005

STUDY COMPLETION DATE: October 6, 2005

8598 Commerce Drive

Easton, Maryland 21601 USA

(410) 822-8600

Page 1 of 25GOOD LABORATORY PRACTICE COMPLIANCE STATEMENT

This study was conducted in compliance with Good Laboratory Practice Standards as published by

the U.S. Environmental Protection Agency in 40 CFR Parts 160 and 792, August 17, 1989 and OECD

Principles of Good Laboratory Practice, (ENV/MC/CHEM (98) 17), with the following exception:

Test substance characterization and stability under storage conditions at the test site were not

determined in accordance with Good Laboratory Practice Standards.

STUDY DIRECTOR: 

### \



# /c>-6-

36-

DATE

Chemist

SPONSOR APPROVAL:

Sponsor's Representative DATE

# Wildlife httemati~nal, Ltd. Project Number 523~-113

QUALITY ASSURANCE STATEMENT

This study was examined for compliance with Good Laboratory Practice Standards as published by

the U.S. Environmental Protection Agency in 40 CFR Parts 160 and 792, August 17, 1989 and OECD

Principles of Good Laboratory Practice (ENV/MC/CHEM (98) 17). The dates of all inspections and audits

and the dates that any findings were reported to the Study Director and Laboratory Management were as

follows:

DATE REPORTED TO:

ACTIVITY: DATE CONDUCTED: STUDY DIRECTOR: MANAGEMENT:

Protocol August 9,2005 August 10,2005 August 17,2005

Sample Preparation September 9, 2005 September 9,2005 September 13,2005

Raw Data and Draft Report September 28-29,2005 September 29,2005 October 5, 2005

Final Report October 6, 2005 October 6,2005 October 6, 2005

All inspections were study-based unless otherwise noted.



# # (-!!

, 

## io-6-og

J&es H. Coleman 

## - DATE

Quality Assurance Representative-4 

### -

REPORT APPROVAL

SPONSOR: Infineurn USA, L.P.

TITLE:

WILDLIFE NTERNATIONAL, LTD. PROJECT NUMBER: 523C-113

STUDY DIRECTOR:



### /3- 

## 6-05



## rank J. &od, 

### BS. DATE

Chemist

MANAGEMENT:

Willard B. Nixon, ~h.d DATE

Director of Chemistry

# W ildlife 

# I nternational, 

# L td. Project Number 523C-113

- 5 -

TABLE OF CONTENTS

Title/Cover Pa ge ............................................................................................................... ...................... 1

Good Laboratory Practice Compliance Statement .................................................................................. 2

Quality Assurance Statement

.................................................................................................... .............. 3

Report Approval ................................................................................................................ ..................... 4

Table of Contents.............................................................................................................. ...................... 5

Summary........................................................................................................................ ......................... 7

Introduction ................................................................................................................... ......................... 8

Objective...................................................................................................................... ........................... 8

Experimental Design ............................................................................................................ .................. 8

Materials and Methods.......................................................................................................... .................. 8

Test Substance................................................................................................................. ............... 8

Reference Standard............................................................................................................. ............ 8

Solvents and Reagents.......................................................................................................... .......... 9

Stock Preparation.............................................................................................................. .............. 9

Test Procedure................................................................................................................. ............... 9

Results ........................................................................................................................ .......................... 10

Conclusions .................................................................................................................... ...................... 10

References ..................................................................................................................... ....................... 11- 6 -

TABLE OF CONTENTS

- Continued -

TABLES

Table 1 Typical Operating Parameters for Automatic Titrator ................................................ 12

Table 2 pK Values ofSUMMARY- 8 -

INTRODUCTION

Tests were performed to determine the dissociation constant of the test substance in water at 20oC.

This study was conducted by- 10 -

was degassed with nitrogen to remove carbon dioxide prior to use. Each sample was equilibrated to

20±1°C in a water bath then transferred into a beaker. The samples were then titrated against standardized

0.001 N NaOH. At least ten incremental additions were made before the equivalence point and the

titration was carried out past the equivalence point. Values of pK were calculated for a minimum of ten

points on the titration curve. The dissociation constant (K

a ) and pK

a were determined as follows:

pK

a = pH – log([B]/[HB])

Antilog (-pK

a ) = K

a

where pH = pH of test solution at any point

[B] = concentration of ionized species

[HB] = concentration of unionized species

RESULTS

The calculated pK value for 4-nitrophenol is summarized in Table 2, and a representative plot of the

titration curve is presented in Figure 1. The pK

a value for 4-nitrophenol was 7.15 at 20.0 ° C. The

reference substance result was in good agreement with the literature value.

The calculated pK values for the test substance are summarized in Table 2, and a representative plot

of a titration curve is presented in Figure 2. The mean pK

a value was 4.38 (SD = 0.0341, CV = 0.779%) at

20±1 ° C. Representative titration data and pK

a calculations for the test substance are summarized in Table

3

CONCLUSIONS

The pK

a value of the test substance was determined to be 4.38 (SD = 0.0341, CV = 0.779%) at

20±1°C.3

- 11 -

REFERENCES

1. Organisation for Economic Cooperation and Development. 1981. Guideline for Testing of

Chemicals, 112: Dissociation Constants in Water.

2. Product Properties Test Guidelines. 1996. OPPTS 830.7370. Dissociation Constants in

Water.

3. American Society for Testing and Materials. 1991. Standard Specification for Reagent Water.

D1193-91, ASTM Section II Water and Environmental Technology, Vol. 11.01:45-47.

4.Appendix 1

Protocol- 21 -- 22 -- 23 -- 24 -- 25 -

Appendix 2

Personnel Involved in the Study

m

1. Willard B. Nixon, Ph.D., Director of Chemistry

2. Raymond L. Van Hoven, Ph.D., Scientist

3. Frank J. Lezotte, B.S., Chemist