NSWC/WOL/TR 75-35 



was also developed based on the thin-layer chromatography .^ Methods 

 for the analysis of any other explosives used in t he underwater 

 explosion program would have to be developed. 



TNT, RDX, Tetryl 



A 100-ml water sample is extracted with 30 to 40 of 

 benzene; the benzene is evaporated to a small volume and injected 

 into a gas chromatograph equipped with a high temperature nickel-63 

 electron capture detector. Chromatographic traces of the water 

 extracts are compared to chromatographic traces of standard solutions 

 of TNT, RDX, Tetryl. Retention times and areas of peaks are measured 

 by means of an automatic digital integrator to an accuracy of + 1 

 sec. for retention time and an integration area count of approximately 

 9 counts/mm 2 . Detection levels for TNT, RDX, and Tetryl have been 

 determined to be 2, 5, and 20 parts per trillion, respectively, under 

 normal routine working conditions. 



HMX 



A 100-ml water sample is extracted with four 2 5-ml portions 

 of benzene. The combined benzene extracts are evaporated under 

 reduced pressure (17 mm/20°C) with a water aspirator to dryness. 

 The residue is taken up in 1.0 ml of acetone. A total of 20- 1 are 

 spotted in four 5- 1 portions as one spot with drying between spott- 

 ing onto a 0.3 mm silica gel HF-254 thin-layer glass plate. Standard 

 solutions of HMX are similarly spotted to the right and to the left 

 of the unknown, and the thin-layer plate is developed in an ascending 

 manner with benzene/acetone, 4:1, as eluent. After air drying, the 

 TLC plate is placed in a ultraviolet cabinet, and zones for HMX are 

 located as dark spots under 254 mm radiation. 



In order to determine the HMX present, the dark areas are 

 marked with a needle and photographed with a polariod camera with 

 transparency film. The developed film is projected by means of a 

 lantern slide projector onto a sheet of white paper 3 to 4 feet away, 

 and the area for the HMX spots traced with a pencil. The standard 

 and sample area are measured by means of a precision planimeter. 

 The weight of HMX in the unknown spot is calculated from the 

 following : 



27 Glover, D. J. and Hoffsommer, J. C. , "Thin-Layer Chromatographic 

 Analysis of HMX in Water", Bull. Environ. Contaim. Texicol. 10 , 

 302 (1973). 



51 



