Environmental Engineering Reference
In-Depth Information
Preparation of the catalase solution
: For 50,000 units of catalase solution,
add 5 mg of catalase to 2 mL water in a 10 mL glass bottle, then mix up by shak-
ing gently. This solution can be used for one week by keeping it in a refrigerator.
For 500 units of catalase solution, add 100
μ
L of 50,000 units catalase solution to
10 mL water. Such a solution must be freshly prepared each time.
Preparation of peroxidase solution
: Add 0.022 mg of peroxidase to 5 mL
water in a 10 mL glass bottle, then mix up by shaking gently. This solution can be
used for two weeks by keeping it in a refrigerator. Add 250
μ
L of the peroxidase
solution to approximately 100 mL of
p
-hydroxyphenyl acetic acid solution.
NaOH solution
: Prepare a fresh 0.6 M NaOH solution.
Preparation of standard H
2
O
2
solution
: Original H
2
O
2
(30 %; KANTO
Chemical Co., Japan) was considered as 10 M, then 1 mL of that H
2
O
2
solution
was used to prepare 100 mM H
2
O
2
. The 100 mM H
2
O
2
solution was then diluted
to concentrations of 0, 100, 200, 300, 500, and 1000 nM, as standards for H
2
O
2
determination.
Preparation of standard ROOH solution
: Original peracetic acid (9 % in
diluted acetic acid; KANTO Chemical Co., Japan) was considered as 1 M, then
10 mL of that peracetic acid solution was used to prepare 100 mM ROOH. The
100 mM solution was then diluted to concentrations of 0, 100, 200, 300, 500, and
1000 nM as standards for ROOH determination.
2.2 Analytical Procedure
A flow injection apparatus should be used, of which a scheme is provided in Fig.
6
(Sakugawa et al.
2000
; Fujiwara et al.
1993
). The instrument shown consists of
an auto sampler (TOSOH, model AS8020), fluorescence detector (Shimadzu:
RF-10AXL), plunger pump (Sanuki Ind. Co., model 4P2U-4016), and recorder
(Shimadzu: C-R5A Chromatopac) (Fig.
7
) (Fujiwara et al.
1993
).
Fluorescence detector
(Ex/Em=320/400 nm)
Pump (ml/min)
Sample (100 µl)
Triple connector
0.50
Carrier MQ
water
Waste
Auto-sampler
Results output
0.12
0.6 M NaOH
Recorder: Chromatopac
Fig. 7
Modified flow diagram for measuring H
2
O
2
and ROOH concentrations in natural waters.
Data source
Fujiwara et al. (
1993
)
