HIRANUMA APPLICATION DATA

Watercontents

Karl Fischer Titrator

Data No. KF17

Apr. 19,2018

Sugars – KF Volumetry, Powder Sample
Glucose, fructose, and sucrose

1. Abstract
Water contents of sugars could be determined by Karl Fischer volumetric titrator. In volumetric titration,
titrant have a factor 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 by sample
measurement.
This application introduces an example for the water determination in glucose, fructose, and sucrose. Sugars
have tendency to dissolve in formamide. Therefore a mixed solvent of formamide and methanol was chosen as
the titration solvent.

2. Apparatus and Reagents(1) Apparatus
Titrator：

Hiranuma Karl Fischer Volumetric titrator

AQV-series

Titration cell：Standard Cell, without drain valve

P/N D327511-1

Powder funnel：

less than 13 mm outer diameter of leg

Titrant：

HYDRANAL Composite 1 (Honeywell)

Methanol：

HYDRANAL Methanol (Honeywell)

Formamide：

HYDRANAL Formamide dry (Honeywell)Titration solvent：Mixed solvent of methanol and formamide at a volume ratio of 1: 2

(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 Parameters
Condition File
Cal Mode

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

30sec

Max Volume

20mL

Min Feed Vol.

0.01

mL

0min

S.Timer
KF Factor

1.0868mg/mL

KF Buret No.

1KF Speed(OUT)

12mL/minKF Speed(IN)12mL/minBack Ground
Sample Size Input

OFFEvery TimeBlank Value

0Unit Mode

AUTOmLE.P Detection

uASolvent

FMC.P Level

150µA

E.P Level

200µA

0g

Auto Interval

Table 4.2 Results of water content measurement in sugars
SampleSamplesize (g)Glucose0.7383

Titrant
volume(mL)
1.410.68050.4549Fructose

SucroseWater(mg)Watercontent (ppm)

1.532

2075.0

1.27

1.380

2028.0

0.89

0.967

2126.00.6485

0.35

0.380

586.0

0.7050

0.38

0.413

585.8

0.5965

0.32

0.348

583.40.4116

0.29

0.315

765.3

0.6171

0.43

0.467

756.8

0.7238

0.51

0.554

765.4

Statistics result

Avg.
SDRSD

2076.3ppm

49.0ppm

2.4%

Avg.
SDRSD

585.1

ppm

1.4ppm

0.2%

Avg.
SDRSD

762.5

ppm

4.9

ppm

0.6

%

5. Note(1) The blanking might become unstable when time has passed since the solvents of methanol andformamide were mixed. The cause could be due to the ammonia generated by mixing solvents. Adding
3 g of benzoic acid to 50 mL of the titration solvent improves the unstable state of blanking.
(2) AQV series released after 2009 have the current detection method which is added as the endpoint
detection method in addition to the conventional potential detection method. The current detection
method doesn’t need the adjustment of the end point parameter “EP level” for each titration solvent
type. In this application, it is set to the current detection method. When performing with the potential
detection method, set “E.P. Detection” to “mV”, and set “E.P. level” to "3” for proper parameter of thetitrant solvent (methanol/formamide).

Keywords：Karl Fischer, Volumetric titration, Sugar