HIRANUMA APPLICATION DATA

Watercontents

Karl Fischer Titrator

Data No. KF12

Apr. 19,2018

Drugs and Medicines – KF Volumetry Powder Sample
Sodium Lauryl Sulfate and Benzalkonium Chloride

1. Abstract
Water contents of drugs and medicines could be determined by Karl Fischer volumetric titrator. In
volumetric titration, titrant have a titer which means the capacity to react with water per 1 mL of titrant. Factor
is pre-determined before sample measurement and water content of sample is calculated from consumed titrant
volume within sample measurement.
When the sample is solid, firstly sample is measured by direct injection into the cell. Dehydrated methanol isused for titration solvent. The titration solvent may change to a composition suitable for dissolving the sample.
If the sample is insoluble to titration solvent, heat-evaporation method is appropriate to these samples.
An example for water contents measurements of sodium lauryl sulfate and benzalkonium chloride performedby direct injection method are introduced here. The measurement method was determined with reference toJapanese Pharmacopeia.
Reference1) Japanese Pharmacopoeia Seventeenth Edition2. Apparatus and Reagents(1) Apparatus
Titrator：

Hiranuma Karl Fischer Volumetric titrator

Titration cell：Standard Cell, without drain valne

Powder funnel：

Outer diameter of leg less than 13 mm

Titrant：

HYDRANAL Composite 5 (Honeywell)Titration solvent：

HYDRANAL Methanol (Honeywell)

AQV-series

P/N D327511-1(2) Reagents

3. Procedure(1) Fill 50 mL of titration solvent into the titration cell as shown in Fig.3.1.
(2) Start blanking to attain stable background.
(3) Put a sample container, powder funnel and spoon on the balance. Record its read (S1 [g]).
(4) Open the glass stopper of titration cell lid to introduce the sample with powder funnel as shown inFig.3.2.
(5) Start titration. Measurement parameter is shown in Table 4.1.
(6) Weigh the sample container, powder funnel and spoon again and record its read (S2 [g]). The

difference of (S1-S2 [g]) is set as sample size.

Titration solvent

Fig.3.1 Preparation of the reagents

Fig.3.2 Introduction of sample with powder funnel

4. Parameters and results
Table 4.1 ParametersCondition File
Cal Mode

0:Sample weight (net)
X=(H-b)×F×1000/SIZEInterval Time

30sec

Max Volume

20mL

Min Feed Vol.

0.01

mL5minS.Timer
KF Factor

5.6884

mg/mL

KF Buret No.

1

KF Speed(OUT)

12

mL/minKF Speed(IN)24mL/minBack Ground

OFFSample Size Input

Every TimeBlank Value0

Unit Mode

AUTO

E.P DetectionmV

C.P Level

150

E.P Level

1Auto Interval

0mL

mVg

Table 4.2 Results of water content measurement in drugs and medicines
Samplesize (g)Titrantvolume(mL)

Water(mg)Watercontent (%)

Sodium lauryl sulfate

0.51620.51560.5156

0.75
0.75
0.75

4.266
4.266
4.266

0.82640.82740.8274

Avg.
SD
RSD

0.8271 %0.0006 %0.07 %

Benzalkonium chloride

0.10050.10880.1002

1.38
1.50
1.40

7.850
8.533
7.964

7.81097.84287.9481

Avg.
SD
RSD

7.8673 %0.0718 %0.91 %

SampleStatistics result

5. Note(1) Sampling tools should be dried up well before use.
(2) Purge and fill the titrant homogeneously into the buret.
(3) Organic solvents which have relatively high volume expansion coefficient are used as a constituent oftitrant. For accurate measurement, factor titration and sample measurement should be performed at thesame room temperature as much as possible.
Keywords：Karl Fischer, Volumetric titration, Pharmacopeia