3 • Operation and Maintenance
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c. Weak acids such as phosphoric or acetic acid can be used as
extraction solvents in small percentages (<5% by volume). Weak
bases such as ammonia can be used at small percentages (<5% by
volume).
d. Noncorrosive additives such as buffers (acetate, phosphate, etc.)
can be used as extraction solvents at moderate percentages.
e. In some cases, nitric or hydrochloric acid can be added directly to
the sample before it is placed into a zirconium cell (not a stainless
steel cell). For example, 1 to 2 mL of 5% to 10% HCl can be
added directly to a soil sample before it is loaded into a zirconium
cell for extraction.
f. Table 3-1
lists the allowable concentrations for several acids and
bases. If a sample needs to be treated with acids stronger than the
concentrations here, pretreat the sample with the concentrated
acid before loading it into a zirconium cell (not a stainless steel
cell). For more details about sample preparation, see
Section 3.1.3
.
Acid or Base Con-
centration
Okay to pump from
solvent reservoir?
(Okay to use SST
or Zr cells)
Add to sample and
transfer to Zr cell?
(Do not use SST
cells)
Add to sample
matrix with ASE
Prep CR and trans-
fer to Zr cell? (Do
not use SST cells)
HCl 8 M No No Yes
HCl 10% No Yes Yes
HCl 0.1 M No Yes Yes
NaOH 8 M No No N/A
NaOH 10% No Yes N/A
NaOH 0.1 M Yes Yes N/A
H
2
SO
4
8 M No No Yes
H
2
SO
4
10% No Yes Yes
H
2
SO
4
5% solution Yes Yes Yes
Table 3-1. Guidelines for Use of Acids and Bases with the ASE 150
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