Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Tetramethylammonium Hydroxide, 1.0 M Aqueous Solution (TMAH; N,N,N-Trimethylmethanaminium Hydroxide) Part 4, Monographs for Reagent Chemicals: General Descriptions, Specifications, and Tests eISBN: 9780841230460 Tom Tyner Chair, ACS Committee on Analytical Reagents James Francis Secretary, ACS Committee on Analytical Reagents
ABSTRACT This monograph for Tetramethylammonium Hydroxide, 1.0 M Aqueous Solution provides, in addition to common physical constants, a general description including typical appearance, applications, and density. The monograph also details the following specifications and corresponding tests for verifying that a substance meets ACS Reagent Grade specifications including: Assay, Color (APHA), Chloride, Residue after Ignition, Potassium, Sodium, and Polarographic Test.
(CH3)4NOH
Formula Wt 91.15
CAS No. 75-59-2
GENERAL DESCRIPTION Typical appearance . . . . . . . . . . . . . . . . . . . colorless to straw-colored liquid Applications . . . . . . . . . . . . . . . . . . . . . . . . buffer; titrant; ion pair reagent Density . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.0
SPECIFICATIONS General Use Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.0 ± 0.02 M as (CH3)4NOH Maximum Allowable Color (APHA) . . . . . . . . . . . . . . . . . . . . . . 10 Chloride (Cl) . . . . . . . . . . . . . . . . . . . . . . 0.03% Residue after ignition. . . . . . . . . . . . . . . . . 5 ppm Potassium (K) . . . . . . . . . . . . . . . . . . . . . . 2 ppm Sodium (Na) . . . . . . . . . . . . . . . . . . . . . . . 2 ppm
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4398 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
Specific Use Polarographic test . . . . . . . . . . . . . . . . . . . Passes test
TESTS Assay (By acid–base titrimetry). Pipette 25.0 mL into a 250 mL conical flask. Add 100 mL of water and 0.15 mL of phenolphthalein indicator solution, and titrate with 1 N hydrochloric acid volumetric solution until the solution becomes completely colorless.
Color (APHA) [Part 2: Measurement of Physical Properties; Color (APHA); Procedure for Color (APHA)].
Chloride [Part 2: Colorimetry and Turbidimetry; Chloride]. Dilute 1.0 mL to 10.0 mL with water in a volumetric flask. Mix well. Pipette 1.0 mL into 15 mL of dilute nitric acid (1:15). Filter, if necessary, through a small chloride-free filter, and add 1 mL of silver nitrate reagent solution. Any turbidity in the sample solution should not exceed that produced by 0.03 mg of chloride ion (Cl) in an equal volume of solution containing the quantities of reagents used in the test.
Residue after Ignition [Part 2: Gravimetric Methods; Residue after Ignition]. Evaporate 200.0 g in a tared, preconditioned platinum dish to dryness in a hood, and ignite.
Potassium and Sodium (By flame AAS, [Part 2: Trace and Ultratrace Elemental Analysis; Atomic Absorption Spectroscopy; Analysis; Procedure for Flame AAS]).
For the Determination of Potassium and Sodium
S a m p l e S t o c k S o l u t i o n . Evaporate 50.0 g to dryness in a platinum crucible, and take up the residue in 5 mL of 5% nitric acid solution. Transfer to a 100 mL volumetric flask, and dilute to the mark with 5% nitric acid solution (1 mL = 0.50 g).
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4398 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
For the Determination of Potassium and Sodium
Element
Wavelength (nm)
Sample Wt (g)
Standard Added (mg)
Flame Type*
Background Correction
K
766.5
10.0
0.02; 0.04
A/A
No
Na
589.0
10.0
0.01; 0.02
A/A
No
*A/A is air/acetylene.
Polarographic Test [Part 2: Direct Electrometric Methods; Polarographic Analysis]. Cathode . . . . . . . . . . . . . . . . . . . . . . . . . Dropping Hg electrode Anode. . . . . . . . . . . . . . . . . . . . . . . . . . . Pt wire Reference . . . . . . . . . . . . . . . . . . . . . . . . Similar saturated calomel electrode: make up with 1.0 M tetrabutylammonium chloride Deoxygenate the TMAH with nitrogen until minimum background current is achieved (approximately 5 min). By using a drop time of 1 s, scan at 0.01 V/s from –1.2 to –2.6 V vs SCE with a sensitivity of 0.5 µA full scale with modulation amplitude of 50 mV. The material is acceptable if no impurity current greater than 0.05 µA is observed.
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4398 ACS Reagent Chemicals, Part 4
