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Talanta 74 (2008) 1026–1031

A reproducible method for determination of nitrocellulose in soil

Denise K. MacMillan a,∗, Chelsea R. Majerus b, Randy D. Laubscher c, John P. Shannon c

a Engineer Research and Development Center, Environmental Laboratory, 3909 Halls Ferry Road, Vicksburg, MS 39180, USAb University of Nebraska at Omaha, S 60th and Dodge, Omaha, NE 68132, USA

c SpecPro, Incorporated, 3909 Halls Ferry Road, Vicksburg, MS 39180, USA

Received 16 March 2007; received in revised form 8 August 2007; accepted 9 August 2007Available online 19 August 2007

bstract

A reproducible analytical method for determination of nitrocellulose in soil is described. The new method provides the precision and accuracyeeded for quantitation of nitrocellulose in soils to enable worker safety on contaminated sites. The method utilizes water and ethanol washeso remove co-contaminants, acetone extraction of nitrocellulose, and base hydrolysis of the extract to reduce nitrate groups. The hydrolysate ishen neutralized and analyzed by ion chromatography for determination of free nitrate and nitrite. A variety of bases for hydrolysis and acidsor neutralization were evaluated, with 5N sodium hydroxide and carbon dioxide giving the most complete hydrolysis and interference-free

eutralization, respectively. The concentration of nitrocellulose in the soil is calculated from the concentrations of nitrate and nitrite and the weightercentage of nitrogen content in nitrocellulose. The laboratory detection limit for the analysis is 10 mg/kg. The method acceptance range forecovery of nitrocellulose from control samples is 78–105%.

2007 Published by Elsevier B.V.

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eywords: Nitrocellulose; Propellants; Base hydrolysis; Ion chromatography

. Introduction

Nitrocellulose (NC) is used by the military as a component ofolid propellants and blasting materials, and also commerciallyn inks and lacquers. Also known as guncotton, pyroxilin, oryrocellulose, NC is a polymer of cellulose with three hydroxylositions available for nitration per monosaccharide unit (Fig. 1).he degree of nitrate incorporation is expressed as a percent-ge according to weight of nitrogen; a fully nitrated celluloseolymer contains 14.14% nitrogen. The level of nitration influ-nces the chemical properties of NC and, accordingly, its uses.or example, NC with 12.5–13.3% nitrogen content is used asun propellant and NC with lower nitrogen content is used inarnishes and films [1].

Though NC is not toxic, it may be a safety hazard whenxposed to an ignition source, and is a concern to the militarys a potential environmental contaminant at ammunition pack-

∗ Corresponding author. Present address: U. S. Environmental Protectiongency, 109 TW Alexander Drive, Mail Drop D305-02, RTP, NC 27511 USA.el.: +1 919 541 4128.

E-mail address: macmillan.denise@epa.gov (D.K. MacMillan).

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ng and manufacturing sites as well at weapons firing points.uilding demolition on formerly used ammunition facilities isspecially dangerous due to the presence of nitrocellulose in theurrounding soil. Analytical methods for determination of NCn soil have not yielded reproducible, accurate quantitation [2],nd thus have not provided sufficient data quality for decision-aking and ensuring worker safety. Some methods measureC through quantitation of nitrate and nitrite formed duringase hydrolysis, which has long been known to degrade NC [3].u recently utilized alkaline hydrolysis combined with sonol-sis to digest nitrocellulose-containing propellants as a step intreatment technology [4]. An automated analytical method

5] developed by the United States Army Toxic and Hazardousaterials Agency (USATHAMA) is used by some commercial

aboratories for determination of NC in soil. The reported detec-ion limit of 60 mg/kg provides sufficiently sensitivity, but theethod requires a 12 h extraction prior to hydrolysis, uses aow injection analyzer which may not be standard equipment inommercial analytical laboratories, and is difficult to implement

ccurately and reproducibly [2].

Methods for detection of nitrocellulose in matrices other thanoil have been developed. Methods such as thin layer chro-atography for detection of nanogram quantities of NC on hand

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wabs and to qualitatively differentiate NC used as a propel-ant from NC used in ink are described by Yinon and Zitrin6]. Pyrolysis/gas chromatography/mass spectrometry has beensed for qualitative identification of nitrocellulose residues afterydrolysis of wastewater containing nitrocellulose fines [7].lectrochemical detection coupled with size-exclusion chro-atography was identified for detection of trace NC in paints,

acquers, wood-filler, explosives, and other materials [8].The goal of this work was to develop an analytical method for

C in soil that is fast, uses instrumentation that is commonlyvailable to environmental analytical laboratories, and yieldsata with sufficient precision and accuracy, such as are observedor EPA method 300.1 [9] for determination of inorganic anions,o enable appropriate site decisions. The method described heres amenable to use by typical environmental analytical laborato-ies since it uses familiar techniques and instrumentation likelyo be available already. The method is initiated with two sol-ent rinses to eliminate interfering co-contaminants prior to NCxtraction with acetone and base hydrolysis. The concentrationsf nitrate and nitrite released upon hydrolysis are determined byon chromatography and are used, along with an estimate of theercentage of NC nitrogen content, to calculate the concentra-ion of NC in the soil. Sensitivity, accuracy, and precision forhis method are achieved through reduction of chromatographicnterferences and incorporation of an optimized hydrolysis step.

. Experimental

All chemicals, reagents, and solvents were obtained fromisher Scientific (Pittsburgh, PA) unless otherwise noted. Stan-ard solutions were prepared from NC (12% nitrogen) (Aldrich,t Louis, MO) that was dried to constant weight in a vacuumesiccator in the dark. Dried NC (4.166 g) was dissolved incetone (Burdick and Jackson, Muskegon, MI) to give a finaloncentration of 4.17 g/L NC. Nitrocellulose control samplesere prepared by spiking 10 g Ottawa sand with 1.0 mL NC

tandard solution for a final NC concentration of 417 mg/kg

nitrogen equivalent concentration for NC with 12% nitrogenontent is 50 mg/kg) or nitrogen as nitrate/nitrite concentrationf 20 mg/L in the hydrolysate. Clean sand is frequently used assoil surrogate for control samples for environmental analyt-

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a 74 (2008) 1026–1031 1027

cal methods. The sand was rinsed with acetone and allowedo dry prior to addition of the standard solution. The spikingolvent was also allowed to evaporate from the control samplesrior to proceeding. Soil samples, which were collected near aight anti-tank weapon (LAW) firing point on Canadian Forcease Gagetown, New Brunswick, Canada, were the kind giftf Mr. Alan Hewitt (Cold Regions Research and Developmentaboratory, Hanover, NH). Samples were collected at points–1, 1–2, 2–5, 5–10, 10–20, 30–40, and 40–50 m behind thering point. Background samples were collected from outside

he training zone. The soils were air dried, passed through a #10ieve (<2 mm), and the fines ground in a puck mill (LabTech Essaty. Ltd., Bassendean, WA, Australia) for five 1 min intervalsrior to preparation for analysis. For control and soil samples,0 g sand or soil were stirred at 30 rpm on a rotary stirrer with0 mL reagent grade water for 10 min. For samples expected toave high concentrations of NC present, 0.5–2.0 g sample sizesere used to minimize dilution of the final extract. The stirred

amples were centrifuged by using a swinging bucket rotor atoderate speed for 10 min or until the supernatants were clear,

fter which the supernatants were decanted and discarded. Theater rinse step was repeated once. A 10 mL aliquot of ethanol

VWR International, Inc., West Chester, PA) was added to eachample after the water rinses. Samples were stirred for 10 minn a rotary stirrer at 30 rpm, centrifuged at moderate speed fornother 10 min or until the supernatants were clear. The ethanolayer was decanted and discarded. Acetone (15 mL) was thendded to each sample, and the samples were again stirred andentrifuged as described previously for the water and ethanolashes. Once the supernatant was clear, it was decanted and

eserved in a clean 50 mL polypropylene centrifuge tube. Thecetone extraction was repeated and the extracts combined. Thextract was evaporated to dryness under a gentle stream oforced air. The dried extracts were combined with base, and theials were placed in a boiling water bath. Optimal hydrolysisime was determined to be 10 min. Bases evaluated for optimalydrolysis were sodium hydroxide (NaOH), calcium hydroxideCa(OH)2), and ammonium hydroxide (NH4OH). After cooling,he hydrolyzed samples were diluted with 20 mL reagent waternd adjusted to pH 8 by addition of acid. Several acids werevaluated for neutralization including phosphoric acid, aceticcid, hydrochloric acid, and sulphuric acid. Dionex (Sunnyvale,A) OnGuard ion exchange clean-up cartridges were used in

ome instances to reduce pH and interferences prior to analy-is. Optimal chromatography with minimal interferences wasbtained by neutralization with a flow (approximately 2 L/min)f industrial grade (98.5%) compressed carbon dioxide (Lin-eld, Lincoln, NE) after which the sample was diluted to a finalolume of 25 mL with reagent water. The hydrolysates werenalyzed for nitrate and nitrite according to EPA method 300.19] by using a Dionex DX-120 ion chromatograph equippedith a Dionex AS14 Ionpak column and a conductivity detec-

or. The mobile phase was 0.5 M carbonate: 0.5 M bicarbonate

nd the flow rate was 1.8 mL/min. Appropriate quality con-rols specified in the EPA method were met. Potassium nitratend sodium nitrite were used as standards and were obtainedrom Mallinckrodt Laboratory Chemicals (Phillipsburg, NJ).

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028 D.K. MacMillan et al. / T

he nitrocellulose concentration was calculated from the sumf the concentrations of nitrate and nitrite and the percentagef NC nitrogen content. For purchased NC, the percent nitro-en provided by the vendor was used for the calculation. Foreal-world samples, the nitrogen percentage of the NC propel-ant from the particular ordnance used at the collection site, ifnown, could be incorporated into the calculation.

To evaluate whether co-contaminant explosives inamples containing NC would create interferences, threeand samples were spiked with 100 mg/kg each of the4 explosives included in the EPA SW-846 Method330 [10] target analyte list (HMX (octahydro-1,3,5,7-etranitro-1,3,5,7-tetrazocine), RDX (hexahydro-1,3,5-trinitro-,3,5-triazine), 1,3,5-trinitrobenzene, 1,3-dinitrobenzene,etryl (methyl-2,4,6-trinitrophenylnitramine), nitrobenzene,,4,6-trinitrotoluene, 4-amino-2,6-dinitrotoluene, 2-amino-,6-dinitrotoluene, 2,4-dinitrotoluene, 2,6-dinitrotoluene,-nitrotoluene, 3-nitrotoluene, and 4-nitrotoluene). Explosivestandards were purchased from Supelco (St. Louis, MO). Aecond three sample set was prepared from sand spiked withach of the 14 explosives at a concentration of 100 mg/kglus NC at a concentration of 417 mg/kg (nitrogen equivalentoncentration of 20 mg/L in the extract). Both sample setsere rinsed with water and ethanol, extracted with acetone,

nd hydrolyzed with 5N NaOH as described above. A thirdet of three samples was prepared from sand and the Method330 target analyte mixture components, each with individualoncentrations of 100 mg/kg. For each experiment, 10 g sandamples were used. To evaluate nitrate and nitrite generationrom the Method 8330 analytes alone, the samples in thehird set were not treated with the water and ethanol rinsesrior to acetone extraction and base hydrolysis. Rinsates werenalyzed by modified EPA Method 8330 [10] reverse phase higherformance liquid chromatography (HPLC) for determinationf explosives by using Spectra-Physics (Mountain View, CA)omponents (Model SP8800 pump, Model 8880 Autosamplernd Spectra Focus detector) equipped with a PhenomenexTorrance, CA) C18 Ultracarb 5� ODS (20), 250 mm × 4.6 mmolumn. The mobile phase was 55:45 (v/v, %) methanol:waterith a flow rate of 0.8 mL/min. A 200 �L injection volume wassed. The detector was monitored at 254 and 280 nm. Qualityontrol guidelines specified in the Method 8330 were followednd met. Laboratory reporting limits for the explosives were.0 mg/kg or below for all analytes with the exception of HMXhich had a reporting limit of 2.2 mg/kg.Interferences from nitroglycerin and nitroguanidine were

valuated in separate preparations. For one evaluation,itroguanidine was added to a real-world sample for a finalpike concentration of 5 mg/kg. The sample was extractedccording to the solid phase extraction procedure described inethod 8330 and analyzed by HPLC using a Thermo Scientific

Waltham, MA) Surveyor system with UV 6000 detector mon-tored at 280 nm, the column described above, and 60:40 (v/v,

) methanol:water mobile phase. The sample was also sub-ected in triplicate to the nitrocellulose method described here,ith rinsates collected and analyzed by HPLC for nitroguani-ine. A second sample with a high concentration of nitroglycerin

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a 74 (2008) 1026–1031

resent was prepared for nitrocellulose determination. Residualitroglycerin was determined in the rinsates by HPLC.

An inter-laboratory study was performed to validate theethod. Columbia Analytical Services, Inc (Redding, CA) andT Laboratories (Baraboo, WI) each received seven firing point

amples with NC concentrations ranging from approximately000–20,000 mg/kg for determination by the method describedere.

. Results

Hydrolysis times and bases were evaluated to identify theonditions for complete hydrolysis. Nitrocellulose was extractedrom soil, and then hydrolyzed for 1 h with saturated calciumydroxide solution. Calcium, base, and other interferences wereemoved with ion exchange cartridges. Recoveries of NC afterh were less than 20% of expected due to incomplete hydrolysis.

ncreased digestion efficiency would be expected with longerydrolysis times, but a digestion of more than 1 h exceededhe goal of a fast method. Hydrolysis with weak NaOH for upo 1 h was also incomplete, as standard recoveries were only2–41% of expected. Hydrolysis with ammonium hydroxide,hich would not require subsequent neutralization since thease would boil off as ammonia and water, gave nitrocelluloseecoveries that were in the range of 16–36%. Optimal resultsor hydrolysis were obtained by using a 10 min boil with 5NaOH which yielded NC recoveries above 75%. Shorter boil

imes of 1 or 3 min gave unacceptable recoveries below 50%,ikely due to incomplete hydrolysis. Su observed similar resultsith lower base concentrations and hydrolysis temperatures [4].onger boil times also resulted in low nitrate and nitrite recov-ry, likely due to loss of nitrogen as nitrogen oxides or otheraseous species.

Several acids were evaluated for neutralization of theydrolysate and generation of interference-free ion chro-atograms. Phosphoric acid neutralization gave broad,

bundant phosphate peaks in the ion chromatograms. Samplesequired dilution over a range from 1:10 to 1:100, depending onhe sample, to prevent co-elution of phosphate and nitrate. Sam-les were applied to cation exchange columns to remove basend other interferences, but sufficient co-contamination was notemoved to warrant continued use. Sulphuric acid neutralizationenerated sulphate ions in the sample, but since sulphate elutesinutes later than nitrate and nitrite with this column/mobile

hase combination, was less likely to interfere with nitrateetection. Use of sulphuric acid did add an unidentified broadeak in the same retention time region as nitrite and nitrate,owever.

Carbon dioxide proved to be most effective for neutralizationf the hydrolysate, and yielded chromatograms that were freef interferences. When used with the 10 min hydrolysis withN NaOH, average recovery of nitrocellulose was 91.6%. Theontrol chart range calculated according to 3 standard devia-

ions around the mean was 78–105% (Fig. 2 ). The relativetandard deviation was 4.7%. This range compares favorablyo the acceptable range of recovery of 75–115% for laboratoryortified blanks specified in EPA method 300.1 [9].

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Laboratory detection limit studies were performed accord-ng to the method described in the Federal Register [11]. A setf seven sand samples was spiked with 20 mg/kg dried nitro-ellulose and subjected to all steps in the method. From theata, 10 mg/kg was calculated to be the method detection limitMDL). The value is six times lower than the MDL reportedor the USATHAMA method [5]. The laboratory reporting limitor NC was set at 20 mg/kg. This value is consistent with guid-nce for establishing the minimum reporting level for an analytendicated in EPA method 300.1 [9] and was used for the con-entration of the low calibration standard for measurement ofC in soil samples. Results that are bracketed by the methodetection limit and the laboratory reporting limit are consideredo be estimated concentrations.

As shown in Table 1, total nitrogen recovery from the samplespiked with the Method 8330 target analytes alone was less thanhe ion chromatography laboratory detection limit. The averageotal nitrogen equivalent concentration produced upon hydroly-is of the Method 8330 analytes without the water and ethanolinses was 17 ± 1 mg/L. The samples spiked with NC and the

ethod 8330 target analytes and subjected to all the steps in thenalytical method gave an average nitrogen equivalent concen-ration of 20 ± 4 mg/L, an amount which is approximately equalo the amount of NC as nitrogen spiked into the samples.

Similarly, a real-world soil sample containing 6700 mg/kg

itroglycerin and 110 ± 9.0 g/kg nitrocellulose was examined inriplicate for residual nitroglycerin after the water rinse steps andhe ethanol rinse step from the nitrocellulose method. The nitro-lycerin concentration for this sample was the highest observed

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d: Not detected.a 10 g sand spiked with Method 8330 analytes and subjected to water and ethanol rb 10 g sand spiked with NC and Method 8330 analytes and subjected to water and ec 10 g sand spiked with Method 8330 analytes and subjected to base hydrolysis wit

a 74 (2008) 1026–1031 1029

or the real-world samples in this study, and thus presented anxcellent test of removal of potential interference. Nitroglycerinas determined by high performance liquid chromatography

s described in SW-846 Method 8330. Nitrocellulose was deter-ined by the method described here. The reported concentration

s the average of the determinations by the three laboratories thatarticipated in the inter-laboratory validation of the method.itroglycerin is present with NC in double-base propellants

o increase energy content. Analysis of the rinsed samples foritroglycerin gave 10.4 ± 1.4 mg/kg residual nitroglycerin, andndicated that, on average, 99.8% of the nitroglycerin originallyresent in the sample had been removed by the initial solventashes. Base hydrolysis of the residual nitroglycerin wouldrovide an insignificant contribution to the already substantialitrocellulose concentration present in this sample.

Method 8330 analysis showed that approximately 91%4.5 ± 0.14 mg/kg) of the nitroguanidine spike was removedith the water rinse and approximately 14% (0.86 ± 0.10 mg/kg)as recovered in the ethanol rinse. Nitroguanidine wasot detected in the acetone extract. For the samples with-ut the spike, nitroguanidine was detected in the waterinse at 0.041 ± 0.004 mg/kg, and in the ethanol rinse at.16 ± 0.01 mg/kg. When the soil sample was analyzed byPLC after solid phase extraction, only 0.015 mg/kg nitroguani-ine was detected, likely due to the differences betweenxtraction methods. Nitroglycerin was observed in the ethanolinse at 44 ± 4.5 mg/kg but not in the water rinse above 7.5 mg/kgor the soil sample alone. When spiked with nitroguanidine,he water rinse from the soil sample yielded 148 ± 27 mg/kgitroglycerin and the ethanol rinse yielded 88 ± 10 mg/kgitroglycerin. The nitroguanidine spiked soil gave a nitro-ellulose concentration of 289 ± 67 mg/kg as compared to66 ± 67 mg/kg nitrocellulose in the soil alone.

The nitrocellulose method was validated through an inter-aboratory study with two commercial environmental analyticalaboratories. Concentrations of nitrocellulose obtained by theommercial laboratories were in good agreement with the val-es obtained in-house, as shown in Table 2 . Relative standardeviations between results for the seven firing point samplesere less than 20% for all samples with the exception of sam-

le FP-7 which showed irreproducible results. The source of theariation in the results from the different laboratories for thisample could not be determined. Duplicate analysis of sampleP-7 in-house gave a relative standard deviation of 29%.

tract) Total N (mg/L extract) %NC recovery Nitrate/nitrite ratio

– – –20 ± 4 101 ± 19 0.41

17 ± 1 – 6.36

inses and base hydrolysis according to the NC analytical method.thanol rinses and base hydrolysis according to the NC analytical method.hout prior solvent rinses.

1030 D.K. MacMillan et al. / Talanta 74 (2008) 1026–1031

Table 2Inter-laboratory study of NC concentration in selected firing point samples

Sample ERDC NC concentration(mg/kg)a

Laboratory 2 NCconcentration (mg/kg)a

Laboratory 3 NCconcentration (mg/kg)a

Average NCconcentration (mg/kg)a

%R.S.D.

FP-1 19,200 23,300 18,800 20,400 12FP-2 81,300 87,600 86,700 85,200 4.0FP-3 103,000 107,000 122,000 110,000 9.0FP-4 71,700 96,500 81,800 83,300 15FP-5 30,800 43,900 38,600 37,800 17FP-6 19,800 21,600 21,100 20,800 4.3FP-7 2,530 2,040

ERDC: Engineer Research and Development Center; FP: firing point; R.S.D.: relativea NC concentration as mg/kg nitrogen as nitrate/nitrite.

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ig. 3. Relationship between NC concentrations and distance behind LAWocket firing point.

The relationship between NC concentrations observed in aet of firing point samples and the distance of the sample col-ection point behind the LAW rocket firing point is shown inig. 3 . LAW rockets are open-ended shoulder-fired weaponshich produce a back-blast danger zone 30 m behind the firingosition and a caution zone 60 m behind the danger area [12].amples collected within 1 m of the firing point have lower NContent than those up to 15 m away. NC concentrations approachackground levels further than 25 m from the source point. TheC distribution is consistent with the observed decrease in nitro-lycerin concentrations with increasing distance detected behindring points where single-base propellants were used [13], andith the danger and caution zones specified by the military.

. Discussion

Nitrocellulose is likely to occur in the environment withther ordnance-related compounds and other species which maynterfere with a precise and accurate determination of NC con-entration. The rinse steps in the analytical method are designedo eliminate ordnance-related co-contaminants as well as inor-anic and organic nitrates in the soil that may be susceptible toase hydrolysis to form free nitrates. Inorganic nitrates formeak outer-sphere complexes with soil and leach into water

eadily; thus a water wash is expected to effectively displaceree nitrates and other potentially interfering anions. In additiono leaching, some organic nitrates such as those from agricultural

ources or waste materials are reduced to free nitrates in water14]. Of organic nitrates such as explosives and ordnance-relatedaterials, nitroglycerin and nitroguanidine show the highestater solubility: 0.15 g/100 mL [6] and 0.44 g/100 mL [15],

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standard deviation. Note: All concentrations are rounded to 3 significant figures.

espectively. NC is slightly less soluble in ethanol (0.6 g/100 mL)han in methanol (1 g/100 mL), and insoluble in water [6].revious methods used only methanol for extraction [5]. Nitro-lycerin, expected to be a co-contaminant with NC originatingrom double-base propellants, is nearly ten times more solublen ethanol [6] than in methanol [15].

The effectiveness of the rinse steps for reducing interferencess demonstrated by the elimination of the Method 8330 targetnalytes from the sand samples, as indicated in Table 1. The aver-ge recovery of NC in the samples that also included the Method330 analytes approximated the amount of the NC spike with aelative standard deviation of less than 20%. Nitrogen as nitratelus nitrite in the samples containing only the Method 8330nalytes was below detectable levels when the samples wereubjected to water and ethanol rinse steps, acetone extraction,nd base hydrolysis. Extracts of samples spiked with the Method330 analytes but not rinsed with water and ethanol prior toxtraction with acetone and hydrolysis yielded an average totalitrogen equivalent concentration of 17 ± 1 mg/L. Had the co-ontaminants not been eliminated by the rinse steps, the averageotal nitrogen concentration in the NC plus Method 8330 analytextracts would be expected to be approximately 37 mg/L basedn the summed contribution of 20 mg/L N from NC and approx-mately 17 mg/L N from the Method 8330 analytes. In additiono this experiment, Method 8330 analysis of a real-world sam-le known to contain both nitroglycerin and NC showed nearlyomplete elimination (99.8%) of nitroglycerin after the sampleas subjected to the water and ethanol rinses of the currentethod. Similarly, chromatographic analysis of a real-world

ample with added nitroguanidine showed that the rinse stepsuantitatively (105%) removed nitroguanidine from the samplerior to the acetone extraction step. These data are evidencehat the water and ethanol rinses prior to acetone extractionf NC from soil are effective for removal of potential inter-erences including nitrated co-contaminants such as explosiveompounds and munitions constituents such as nitroglycerin anditroguanidine.

Interestingly, the nitrate/nitrite ratios for the NC plus Method330 analyte sample extracts and the Method 8330 analyte sam-le extracts (Table 1) are significantly different. Typically, for

C samples analyzed by this method, the observed nitrate/nitrite

atio for the extract was less than 1. As show in Table 1,itrate/nitrite ratio is greater than 1 for the Method 8330 analytenly samples. Since the hydrolysis conditions were identical

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or both sample sets, the difference may reflect mechanis-ic differences in hydrolysis of the ONO2 moieties presentn NC and the NO2 moieties present on the Method 8330nalytes.

Two commercial environmental analytical laboratories per-ormed the method and obtained good agreement for results foramples obtained from a LAW rocket firing point with the excep-ion of one sample with low levels of NC. The result obtainedy one laboratory for the low level sample was nearly twice theoncentration obtained by the other commercial laboratory andhis laboratory. The inter-laboratory reproducibility for the fir-ng point samples is otherwise within the acceptable range foreproducibility between duplicate samples for Method 300.1 foretermination of nitrate and nitrite.

. Conclusion

An analytical method for determination of nitrocellulose inoil has been demonstrated with standards and with soils from aAW rocket firing point. The method incorporates solvent rinseshich effectively reduce the presence of co-contaminants, baseydrolysis to free nitrate and nitrite, and conductivity detection.he method was performed by two commercial laboratories inddition to the development laboratory with satisfactory repro-ucibility. The laboratory detection limit for the method wasalculated to be 10 mg/kg. Acceptable recovery performance forpiked samples was shown to be 78–105% with relative standardeviation equalling 4.7%.

cknowledgements

The use of trade, product, or firm names in this paper is forescriptive purposes only and does not imply endorsement by the.S. Government. Unless otherwise noted the work describedere was conducted under the U.S. Army Environmental Qualitynd Installations Program, Engineer Research and Developmententer. Permission was granted by the Chief of Engineers toublish this information.

eferences

[1] J. Akhavan, The Chemistry of Explosives, second ed., Royal Society ofChemistry, Cambridge, UK, 2004, p. 32.

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a 74 (2008) 1026–1031 1031

[2] ESTCP, Environmental Security Technology Certification Program, Costand Performance Report CU-0130, Applied Innovative Technologies forCharacterization of Explosives-Contaminated DoD Building Foundationsand Underlying Soils, February 2004, http://www.estcp.org/documents/techdocs/cu-0130.pdf.

[3] W.O. Kenyon, H.L. Gray, Am. Chem. Soc. J. 58 (8) (1936) 1422.[4] T.-L. Su, Alkaline Hydrolysis of Nitrocellulose and Nitrocellulose Con-

taining Rocket Propellants and Biodegradability of Post-HydrolysisProducts, UMI Number 9736478, UMI Company, Ann Arbor, MI,1997.

[5] J.J. Barkley, D.H. Rosenblatt, Automated nitrocellulose analysis, U.S.Army Medical Bioengineering Research and Development Laboratory,Technical Report 7807, ADA067081, 1978.

[6] J. Yinon, S. Zitrin, Modern Methods and Applications in Analysis of Explo-sives, John Wiley and Sons Ltd., West Sussex, UK, 1993, pp. 8, 13–14,35–36.

[7] D. Cropek, B. Dankowski, Sonolysis of Nitrocellulose Fines, 2000,ERDC/CERL TR-00-14, Engineering Research and DevelopmentCenter, Construction Engineering Research Laboratory, Champaign, IL.http://www.cecer.army.mil/TechReports/cropek sonolysis NCfines/cropeksonolysis NCfines.pdf.

[8] J.B.F. Lloyd, Anal. Chem. 56 (1984) 1907.[9] U.S. EPA, United States Environmental Protection Agency, Method

300.1: Determination of Inorganic Anions in Drinking Water by IonChromatography, U.S. Environmental Protection Agency National Expo-sure Research Laboratory, Cincinnati, OH, 1999. http://www.epa.gov/safewater/methods/pdfs/met300.pdf.

10] U. S. EPA, United States Environmental Protection Agency, Method8330 Nitroaromatics and Nitramines by High Performance Liq-uid Chromatography (HPLC), in Test Methods for Evaluating SolidWastes Physical Chemical Methods (SW-846), 1994, http://www.epa.gov/epaoswer/hazwaste/test/pdfs/8330.pdf.

11] Federal Register, Guidelines Establishing Test Procedures for the Anal-ysis of Pollutants, 40 cfr part 136, 1999, http://www.access.gpo.gov/nara/cfr/waisidx 99/40cfr136 99.html.

12] Marine Corps University, Introduction to Countermechanized and Mech-anized Weapons, The Basic School, US Marine Corps, B2113 StudentHandout, 2002, http://www.usna.edu/USMCInfo/Documents/Pubs/b2113.pdf.

13] T.F. Jenkins, S. Thiboutot, G. Ampleman, A.D. Hewitt, M.E. Walsh,T.A. Ranney, C.A. Ramsey, C.L. Grant, C.M. Collins, S. Brochu,S.R. Bigl, J.C. Pennington, Identity and Distribution of Residuesof Energetic Compounds at Military Live-Fire Training Ranges,2005, ERDC TR-05-10, Engineer Research and Development Cen-ter, Cold Regions Research and Engineering Laboratory, Hanover, NH.http://www.crrel.usace.army.mil/techpub/CRREL Reports/reports/ERDC-

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14] D.L. Sparks, Environmental Soil Chemistry, Academic Press, San Diego,CA, 1995, pp. 133–186 (Chapter 5).

15] M.J. O’Neill (Ed.), The Merck Index, 13th ed., Merck and Co. Inc., White-house Station, NJ, 2001, p. 1135.