NSWC/WOL/TR 75-35 



After evaporation of the benzene extract under reduced pressure 

 ( 17-20mm/20°C) , the flask is rinsed with 1.0 ml of pesticide quality 

 benzene and transferred to a 5.0 ml test tube. The benzene is again 

 completely removed under reduced pressure. A total of 0.050 ml of 

 benzene is added to the residue and 0.025 ml of this solution are 

 spotted along a narrow band in 5 separated spots onto a ChromAr 500 

 TLC sheet. Simultaneously, a standard mixture of TNT, RDX, and 

 Tetryl in benzene is spotted to the right of this band, as a guide. 



The fluorescent ChromAr sheet is developed in an ascending 

 manner with hexane/acetone :45/5 as eluent. After air-drying the 

 ChromAr sheet for 5 minutes, zones for the standard TNT, RDX, and 

 Tetryl are located as dark spots under 254 mm UV light. Correspond- 

 ing areas to the left of these standards are cut out and transferred 

 to a 5-ml beaker. These ChromAr discs are extracted 3 to 4 times 

 with a total of 1.0 to 1.5 ml of benzene. The benzene extracts are 

 combined into a 2.0 ml sample tube with a tapered bottom and the 

 benzene completely removed under reduced pressure. A total of 50 y 1 

 of benzene is added to the tapered tube together with 5^ 1 of 

 o-dinitrobenzene (4.5 x 10~1° g/ 1) as internal standard. After 

 thoroughly mixing, a 5 to 6y 1 injection of this solution is placed 

 into the gas chromatograph. At this point, the procedure follows 

 that reported in Section 4.3.2.2. 



HMX 



HMX is extracted from the sediment sample by the same procedure 

 used in TNT, RDX, and Tetryl. After extraction HMX is determined by 

 the procedure described in Section 4.3.2.2. 



Ammonium Perchlorate 



A sediment sample is stirred with distilled water for several 

 hours, after which the sediment is removed using a centrifuge. 

 Ammonium perchlorate in the solution is measured by the specific 

 ion electrode. 



4.3.4.3 Particulate Carbon 



The particulate carbon in the sediment can be determined with an 

 organic carbon analyzer (Section 4.3.3.4). The sediment sample is 

 first suspended in water, and an aliquot is then withdrawn for the 

 analysis. Samples with sediment and high dissolved solids content 

 pose no problem. However, the analysis is subject to some degree of 

 error if the organic content other than the particulate carbon is 

 relatively high. 



57 



