10.1002/rcm.7385
Enhanced electrospray ionization mass spectrometric detection of hexamethylene triperoxide diamine (HMTD) after oxidation to tetramethylene diperoxide diamine dialdehyde (TMDDD) All chemicals used for synthesis were of reagent grade. Lithium acetate dihydrate (99.999%), acetic acid (99.99%) as well as the LC/MS grade acetonitrile were purchased from Sigma-Aldrich (St. Louis, MO, USA). Sodium acetate (99%; HPLC grade) was obtained from Acros Organics (Geel, Belgium). Ammonium acetate (LC/MS grade) was from Fisher Scientific (Fair Lawn, NJ, USA). Potassium acetate (analytical grade) was purchased from POCH (Gliwice, Poland). Milli-Q water was used throughout all the experiments. Standard solutions of HMTD and TMDDD were prepared daily in acetonitrile. 
HMTD was prepared according to a published procedure.[24] A 25-mL round-bottomed flask was charged at 0 degC with 0.7 g of hexamethylenetetramine and 2.3 mL of 50% H2O2. The mixture was continuously mixed with a magnetic stirrer. After complete dissolution, citric acid (1.15 g) was added in four portions every 15 min. The mixture was left overnight while it was allowed to warm to room temperature. The white precipitate was filtered, thoroughly washed with water, and an approximately 100-mg fraction of the product was dried in a vacuum desiccator. 
TMDDD was synthesized according to the procedure published by Wierzbicki et al.[24] with minor modifications. A portion of HMTD was dissolved in boiling (freshly distilled) n-butyl acetate (1:80 ratio). The solution was filtered into a three-necked flask equipped with a condenser, a thermometer and a capillary (1 mm diameter). This solution was purged with a stream (10-15 mL s-1) of oxygen at 120 degC for approximately 1 h until complete conversion of HMTD. The solution was allowed to cool to room temperature and white crystals were collected on the following day. The product was recrystallized from n-butyl acetate (yield 10%).
Lithium acetate dihydrate
99.999%
%
acetic acid
99.99%
%
Sodium acetate
HPLC grade
99%
%
H2O2
charged
25-mL round-bottomed flask was charged at 0 degC with 0.7 g of hexamethylenetetramine and 2.3 mL
mL
hexamethylenetetramine
charged
0.7 g
g
H2O2
charged
50%
%
H2O2
charged
0 degC
degC
citric acid
added
1.15 g
g
citric acid
added
every 15 min
min
product
dried
100-mg
mg
HMTD was dissolved in boiling (freshly distilled) n-butyl acetate
ratio
1:80
capillary
diameter
1 mm
mm
solution
purged with a stream
10-15 mL s-1
mL s-1
solution
purged
120 degC
degC
solution
purged
1 h
h
product
yield
10%
%