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4.3 Sample
(1) Pretreatment
Samples must be inorganic aqueous solutions. Since most
arsenic compounds have low boiling points, organic samples
should preliminarily be decomposed by wet ashing or other
method.
Floating matter and dust contained in sample should
preliminarily be removed by filtering or other suitable process.
(2) Preparation
In the process of mixing four liquids, a sample is mixed with
reducing agent to convert the arsenic in the sample to trivalent
state. To reduce pentavalent arsenic to trivalent arsenic, it is
necessary to add hydrochloric acid to the sample. The following
are examples of sample preparation methods.
(a) Standard solutions for working curve (arsenic: 0, 1, 2, 5 ug/L)
*
a. Hydrochloric acid (special grade or higher): 10 mL
b. 1 mg/L arsenic standard solution:
0, 10, 20, 50 uL
Add a and b, and adjust the total volume to 20 mL with pure
water.
* Actual concentrations are 0, 0.5, 1, 2.5 µg/L. However, 0,
1, 2, and 5 µg/L values are required for condition input,
since sample is to be diluted twofold.
(b) Sample
a. Hydrochloric acid (special grade or higher): 10 mL
b. Sample solution:
10 mL
Add a and b, and adjust the total volume to 20 mL with pure
water.
NOTE:
When the measurement is continued for long time (more
than 1 h), the absorbance may decrease because of
absorption of analyte into dew inside of the silicone tube
(This will be prominent for Se). In this case, remove the
silicone tube and dry it, then attach again.
Содержание ZA3000 Series
Страница 267: ...3 1 11 3 43 Fig 3 31 Parameter List Window Common conditions The setting of method is thus completed ...
Страница 357: ...5 5 Twin Injection 5 28 Fig 5 24 Dialog Box for Confirming Nozzle Position 7 Click Start measurement ...
Страница 423: ...9 3 5 9 11 Fig 9 14 Diagnosis Log Dialog Box ...
Страница 449: ...10 5 Reflecting on Analysis Conditions 10 24 Fig 10 16 Method Window Unmark the checkbox ...
Страница 455: ...INDEX 4 V Verify 3 34 W Working curve graph 4 1 Wavelength accuracy 9 1 ...
Страница 456: ...INSTRUCTION MANUAL 7J1 9027 000 Ver 1 February 2016 MODEL HFS 4 HYDRIDE FORMATION SYSTEM ...