Analytical chemistry

Turkey is an integral part of the Alpine-Himalayan orogenic belt with a number of tectonostratigraphic units striking in an E-W direction. These belts consist of terranes of different tectonic settings, ranging from oceanic basins to active and passive continental margins. The age of incorporated units of continental margin origin ranges from the Cambrian to the Cenozoic, and includes unmetamorphosed to low-grade Devonian rocks in the Pontides, Taurides and on the Arabian Plate. This paper describes the detailed sedimentology, facies and biostratigraphy of three 900 to 1200 m thick Devonian successions in the Central and Eastern Taurides (Eceli, Halevikdere and Kocadere). During the Devonian, the Central and Eastern Taurides were situated at the northern margin of Gondwana. The sediments described were deposited on this margin in coastal to shelf environments. Despite similar large-scale trends, regional differences in the sedimentary sequences can be distinguished, especially for the lower part of the Devonian. For the first time, sufficient biostratigraphical data have been recovered to allow the successions to be subdivided at a stage scale, permitting their approximate correlation and comparison with the regional lithostratigraphy. The temporal development of sedimentary processes, facies changes, and hinterland signatures recorded in the individual sections have been reconstructed, allowing their correspondence to global events to be recognized and discussed for the first time. The palaeobiogeographic distribution of various organisms within these succession suggests a comparatively narrow sea ('Rheic Ocean') between Laurasia and Gondwana/Peri-Gondwana during the Devonian.

A juvenile cup, disarticulated arm plates, and columnals of the crinoid Arachnocrinus sarizensis n. sp. are described from the Eastern Taurus Mountains of central Turkey. This is the first Paleozoic crinoid based on a cup and arm plates reported from Turkey. Suggested revision of the Gasterocomidae includes transfer of Arachnocrinus and Ancyrocrinus to the family and rejection of Kopficrinus from the family. The stratigraphic range of Arachnocrinus is extended upward into the Middle Devonian from the Early Devonian. The Devonian of Turkey is of special interest because it includes Laurasian and Gondwanan components on different tectonic blocks. The paleogeographic range of Arachnocrinus is extended from the North American plate onto the Anatolian block, which would have been located on the southern edge of the Paleotethys Sea in the Middle Devonian in a shelf basin off the northern coast of Gondwana at approximately 42 • south latitude.

An extensive rescue excavation has been conducted in the ancient harbor of İstanbul (Yenikapı) by the Sea of Marmara, revealing a depositional sequence displaying clear evidence of transgression and coastal progradation during the Holocene. The basal layer of this sequence lies at 6 m below the present sea level and contains remains of a Neolithic settlement known to have been present in the area, indicating that the sea level at~8-9 cal ka BP was lower than 6 m below present. Sea level advanced to its maximum at~6.8-7 cal ka BP, drowning Lykos Stream and forming an inlet at its mouth. After~3 cal ka BP, coastal progradation became evident. Subsequent construction of the Byzantine Harbor (Theodosius; 4th century AD) created a restricted small basin and accumulation of fine-grained sediments. The sedimentation rate was increased due to coastal progradation and anthropogenic factors during the deposition of coarse-grained sediments at the upper parts of the sequence (7th-9th centuries AD). The harbor was probably abandoned after the 11th century AD by filling up with Lykos Stream detritus and continued seaward migration of the coastline.

In the eastern part of the Strandja Massif constituting the east end of the Rhodope Massif, the amphibolite facies basement rocks intruded by Permian metagranites are juxtaposed against the greenschist facies cover metasediments of Triassic-Middle Jurassic protolith age. The distinct metamorphic break between the basement and cover rocks requires a missing metamorphic section. The boundary between the two groups of rocks is a ductile to brittle extensional shear zone with kinematic indicators exhibiting a top to the E/NE shear sense. Footwall rocks are cut by weakly metamorphosed and foliated granite bodies which are clearly distinguished from the Permian metagranites by their degree of deformation, cross-cutting relations and syn-tectonic/kinematic character. Also, hangingwall rocks were intruded by unmetamorphosed and weakly foliated leucogranites. 40 Ar/ 39 Ar data indicate that the ductile deformation from 156.5 to 143.2 Ma (Middle Oxfordian-Earliest Berriasian) developed during the syntectonic plutonism in the footwall. Deformation, and gradual/slower cooling-exhumation survived until to 123 Ma (Barremian). The mylonitic and brittle deformation in the detachment zone developed during Oxfordian-Earliest Berriasian time (155.7-142.6 Ma) and Early Valanginian-Aptian time (136-118.7 Ma), respectively. Our new field mapping and first 40 Ar/ 39 Ar ages demonstrate the existence of an extensional core complex of Late Jurassic-Early Cretaceous age not previously described in the Rhodope/Strandja massifs. Keywords 40 Ar/ 39 Ar geochronology Á Eastern Strandja detachment fault Á Mesozoic Core Complex Á Strandja/Rhodope massifs Á Turkey Electronic supplementary material The online version of this article (

The Devonian Period is represented in Turkey by almost complete non-metamorphic sections of more than 1000 meters, which exhibit varying lithofacial associations. They are parts of thick Paleozoic sedimentary successions in the Pontides, Taurides and Arabian Plate. The tectonic setting and the paleogeographical origin of these terranes is different. Therefore, the litho-and biostratigraphy and facies characteristics of these Devonian successions would enable a comparison and a paleogeographical assignment of these tectono-stratigraphic units. Devonian successions of the Arabian Plate and of the Taurides are represented by facies associations ranging from tidal flat to a deep shelf. Whereas, those of the Istanbul and Çamdag-Zonguldak areas in the Pontides by a deepening upward sequence from a shallow shelf into a basin and a stable shelf, respectively. The Devonian of the Arabian Plate and the Taurides can surely be assigned to Gondwana. A Peri-Gondwanan (Avalonian) setting is suggested for the paleogeographic position of the Devonian of the Pontides.

ICP-OES and LA-ICP-MS instruments routinely used to assess the geochemical properties of the various natural and synthetic materials. In this contribution, the analytical routines and method development procedures of the ICP-OES and LA-ICP-MS facilities installed at the İstanbul University-Cerrahpaşa Geological Engineering Department, Geochronology and Geochemistry Laboratory have been evaluated using well-known international rock standards. Sample preparation techniques, method development, experimental setup and measurement conditions for the both ICP-OES and LA-ICP-MS instruments were discussed and specific analyze results of NIST SRM 614, BCR-2, AGV-2, BCR-2G and AGV-2G were evaluated. Flux-free USGS glass standards were produced by in-house techniques and flux-bearing glasses were produced by fusion of sample with the mixture of ultra-pure lithium-tetraborate, lithium metaborate and lithiumbromide were evaluated and compared with the well-known reference values in the literature. Relative standard deviation (RSD) values for the major oxide measurements for standards given range of 0.0 wt. % to 1.5 wt. %. RSD values for the trace and rare-earth-elements values were mainly lower than 10 wt. %. The results confirm that the both flux-bearing and flux-free glasses reasonably match with the worldwide inter-laboratory values for international standards samples. The combination of these two instruments can be used to conduct geochemistry of various solid earth materials.

Turkey is an integral part of the Alpine-Himalayan orogenic belt with a number of tectonostratigraphic units striking in an E-W direction. These belts consist of terranes of different tectonic settings, ranging from oceanic basins to active and passive continental margins. The age of incorporated units of continental margin origin ranges from the Cambrian to the Cenozoic, and includes unmetamorphosed to low-grade Devonian rocks in the Pontides, Taurides and on the Arabian Plate. This paper describes the detailed sedimentology, facies and biostratigraphy of three 900 to 1200 m thick Devonian successions in the Central and Eastern Taurides (Eceli, Halevikdere and Kocadere). During the Devonian, the Central and Eastern Taurides were situated at the northern margin of Gondwana. The sediments described were deposited on this margin in coastal to shelf environments. Despite similar large-scale trends, regional differences in the sedimentary sequences can be distinguished, especially for the lower part of the Devonian. For the first time, sufficient biostratigraphical data have been recovered to allow the successions to be subdivided at a stage scale, permitting their approximate correlation and comparison with the regional lithostratigraphy. The temporal development of sedimentary processes, facies changes, and hinterland signatures recorded in the individual sections have been reconstructed, allowing their correspondence to global events to be recognized and discussed for the first time. The palaeobiogeographic distribution of various organisms within these succession suggests a comparatively narrow sea ('Rheic Ocean') between Laurasia and Gondwana/Peri-Gondwana during the Devonian.

The İstanbul Pliocene deposits consist of an alternation of sand, clay, and coal in the northern part of İstanbul that characterizes a delta plain deposit on the southern coastal line of the Black Sea. The Pliocene sediments, which are located conformably on the fluvial sediments consisting of coarse clastics, are about 80 meters thick and outcrop as isolated patches in Şile in the east of the İstanbul Strait (Bosphorus) and Kısırkaya in the west. The U/Pb detrital zircon ages obtained from the sands of Kısırkaya and Şile region showed that the Pliocene deposits contain Proterozoic (2396 ± 72-542.4 ± 7.9 Ma), Paleozoic (540 ± 12-258.9 ± 5.2 Ma), Mesozoic (248.8 ± 4.4-71.8 ± 1.2 Ma), and Cenozoic (63 ± 1.8-22.18 ± 0.95 Ma) zircons derived from a piedmont plateau. Presence of the youngest Oligocene-early Miocene zircons (22.18 ± 0.95-31.1 ± 1.2 Ma) reveals that the source of this succession may be the Northwest Anatolia and/or northern Aegean region where magmatic rocks of the same age crop out. In addition to the zircon data in the sandy deposits, trace element geochemistry also shows that the drainage basin of the Pliocene rivers transporting clastics to the basin is located in the southwestern region of İstanbul and flowed into the Black Sea before the formation of the Marmara Sea. These rivers would have been blocked in the early Quaternary by the Marmara Sea depression, which was formed by extensional faults, the product of an approximately N-S extensional tectonic regime in the region. This tectonic regime caused the rapid uplifting of the İstanbul region and the Istranca Mountains in the north of the Marmara, and the eroded flattened areas called the Bursa-Balıkesir plateau in the south, in the form of horsts. Subsequently, before the North Anatolian fault reached the region, it formed deformation structures under the effect of dextral shear in a wide zone in the Marmara region. This tectonic regime was ended when the North Anatolian fault reached and cut the Marmara Sea region in the Latest Quaternary.

Devonian strata, including siliciclastic and carbonate rocks that were deposited in shallow marine to coastal environments, are widely distributed in the eastern Taurides of southern Turkey. To document the regional formation of the Givetian (Middle Devonian)/ Frasnian (Upper Devonian) boundary, a section in the eastern Taurides was studied in high resolution with regard to biostratigraphy, microfacies, sequence stratigraphy, and the global Frasne Event. The integrated biostratigraphic investigation was based on calcareous benthic foraminifers, ostracods, conodonts, and palynomorphs, which provide a biostratigraphic frame that allows to recognize the Givetian/Frasnian boundary. On the basis of the lithological variation in the outcrop as well as on depositional textures and biotic components as observed in thin sections, fourteen microfacies types of both siliciclastic and carbonate rocks can be distinguished. These microfacies are interpreted to have been deposited in settings that range from distal shelf to lagoonal depositional environments. The sequence stratigraphic interpretation allows to recognize two successive depositional sequences. The first one is a complete sequence including lowstand systems tract deposits, overlain by transgressive systems tract and highstand systems tract deposits. The second sequence is only represented by transgressive systems tract sediments. The Givetian/Frasnian boundary corresponds to the highstand systems tract of Sequence 1. The late Givetian Frasne Event can be detected lithologically and can be compared with other areas. Its position is confirmed biostratigraphically.

North of İstanbul, the thick Upper Cretaceous volcanic and volcanoclastic sequence of the Yemişliçay Group is nonconformably overlain by the neritic clastic and carbonate sequence of the Zekeriyaköy Formation. This unit, either placed within the volcanic sequence or interpreted to overlie it, was studied near Zekeriyaköy for its larger foraminifera, previously recurrently referred to as the Maastrichtian. The basal epiclastic sandstone beds of the Zekeriyaköy Formation immediately above the volcanic sequence contain Praesiderolites dordoniensis and rare rudist shells. The higher sandstone and limestone beds comprise assemblages of Lepidorbitoides campaniensis, Orbitoides megaloformis, Vanderbeekia catalana, Siderolites gr. calcitrapoides, Sirtina orbitoidiformis, Praestorrsella roestae, Lenticulina rotulata, Planorbulina sp., agglutinated and rotaliid foraminifera, rudist fragments, bryozoans, and red algae. Lepidorbitoides, the most abundant foraminifera in the studied material, has predominantly L. campaniensis-type embryons with a single auxiliary chamberlet, and rarely, L. bisambergensis-type embryons, characterized by having 2 such chamberlets. The Praesiderolites dordoniensis-Lepidorbitoides campaniensis-Vanderbeekia catalana assemblages, recorded for the first time in Turkey, suggested a late Campanian age for the Zekeriyaköy Formation, with the implication that Late Cretaceous volcanism terminated in the İstanbul region during or prior to the late Campanian. The fauna shows a great resemblance to those from the Late Campanian type-section in Aubeterre (SW France) and Late Campanian fauna of the Pyrenean Basin (N Spain), and correspond to the most eastern record of the European Faunal Province of the Tethys.

The Southeast Anatolian Orogenic Belt (SAOB) consists of various tectono-magmatic and tectono-stratigraphic units such as metamorphic massifs, granitoids, ophiolites and volcanic rocks. In this study, we report new zircon U-Pb LA-ICP-MS ages, Sr-Nd isotope analysis and whole-rock geochemistry from Miocene felsic (dacitic and rhyolitic) rocks cross-cutting the Permo-Triassic Malatya metamorphic complex to determine the source of magmatism and magmatic processes in the region. The zircon U-Pb crystallisation ages are between 16.66 ± 0.23 Ma and 16.83 ± 0.094 Ma, implying the start of the post-collisional volcanism in the Early Miocene (Burdigalian) period. Volcanic rocks have calc-alkaline and high-K calc-alkaline characters. The 87 Sr/ 86 Sr values for the felsic volcanics range between 0.707098 and 0.711703. The initial 143 Nd/ 144 Nd ratios are between 0.512446 and 0.512469, and the εNd values vary from −3.12 to −3.66. The Nd (T DM) model ages are between 1.05 and 1.13 Ga. Negative εNd values and Nd (T DM) model ages show great similarities with the Precambrian basement in Turkey, Iran and the Arabian peninsula. Energy-constrained assimilationfractional crystallisation (EC-AFC) models testing different crustal sources using Sr-Nd isotope data show that primary magmas contain significant crustal melt contributions. Geochemical data indicate that the felsic rocks may have originated from crust-derived melts mixed with lithospheric mantle-derived mafic melts during its residence in the upper crust in a post-collisional tectonic setting.

Hydrogen peroxide (H 2 O 2) is a synthetic precursor and degradation product of peroxide-based explosives, such as TATP. We developed a colorimetric sensor that is selective, sensitive, cost-efficient and easy-to-use in conventional laboratories for the naked eye detection of hydrogen peroxide and for indirect determination of peroxide-based explosives (which are devoid of chromogenic/fluorogenic functional groups). We were able to partly oxidize zero-valent silver nanoparticles (Ag 0 NPs) by H 2 O 2 to Ag + under special conditions, and thus devise an indirect method for trace H 2 O 2 quantification by measuring the absorbance of the blue-colored diimine of TMB (3,3 ,5,5-tetramethylbenzidine) at 655 nm, arising from TMB oxidation with Ag +. TATP was acid-hydrolyzed to H 2 O 2 by an acidic cation-exchanger (Amberlyst-15) for potential field use. The limit of detection (LOD) of the sensor was 20 nM for H 2 O 2 and 0.31 mg L −1 for TATP. Common soil ions did not interfere, and TATP was analyzed in synthetic mixtures of other energetic materials. The responses of detergents, sweeteners, acetylsalicylic acid (aspirin) and paracetamol-based painkiller drugs, used as camouflage material in passenger belongings, were also examined. The developed method was statistically validated against the standard analytical methods of titanium(IV) oxysulfate (TiOSO 4) for H 2 O 2 and GC-MS for TATP using t-and F-tests.

Rapid and inexpensive sensing of explosive traces in soil and post-blast debris for environmental and criminological purposes with optical sensors has recently gained importance. The developed sensing method for nitro-aromatic and nitramine-based explosives is based on dropping an acetone solution of the analyte to an adsorbent surface, letting the solvent to dry, spraying an analytical reagent to produce a persistent spot, and indirectly measuring its reflectance by means of a miniature spectrometer. This method proved to be useful for on-site determination of nitroaromatics (trinitrotoluene (TNT), 2,4,6-trinitrophenylmethylnitramine (tetryl) and dinitrotoluene (DNT)) and nitramines (1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7tetrazocine (HMX)) pre-adsorbed on a poly vinyl chloride (PVC) surface, with the use of different spray reagents for each group of explosives producing different colors. The calibration equations of the tested compounds as reflectance vs. concentration showed excellent linearity (correlation coefficient: 0.998-0.999). The linear quantification interval in terms of absolute quantity of analyte was 0.1-0.5 g. The developed method was successfully tested for the analysis of military explosives Comp B and Octol, and was validated against high performance liquid chromatography (HPLC). The reflectometric sensing method could also be used for qualitative identification of the nitrated explosives on a chromatographic paper. The reagent-impregnated paper could also serve as sensor, enabling semi-quantitative determinations of TNT and tetryl.

In this paper, a simple and rapid nanosensing assay was developed for 3-nitro-1,2,4-triazole-5-one (NTO) exploiting target-directed adsorption by unlabeled gold nanoparticles (AuNPs) and competitive supramolecular association of NTO with melamine (MEL). While AuNPs aggregated in the presence of MEL with a color change from red to blue, AuNPs remained dispersed and retained their original plasmonic red color with the addition of NTO, owing to the hydrogen bonding affinity of the NTO triazole ring to MEL. The concentration of NTO leading to color change could be determined with the naked-eye even at the sub-femtomolar level. Analytical results showed that the absorption ratio (A 520nm /A 630nm) varied linearly with the logarithm of NTO concentration in the range of 3.08 × 10 −16 to 3.08 × 10 −12 mol L −1 with a correlation coefficient of 0.9994. The synthesized and resultant AuNPs (in the presence of NTO and/or MEL) were characterized using ultraviolet−visible spectrophotometry, scanning transmission electron microscopy, attenuated total reflectance-Fourier transform infrared spectroscopy, and ζ-potential measurements. Possible interferences of various energetic substances in synthetic mixtures containing 2,4,6-trinitrotoluene (TNT), 2,4,6-trinitrophenol, hexahydro-1,3,5-trinitro-1,3,5-triazine, and ammonium nitrate, of possible camouflage materials used in passenger belongings such as cationic surfactants (cetyltrimethylammonium bromide and cetylpyridinium chloride), D-(+)-glucose as a representative sugar, acetylsalicylic acid-and paracetamol-based painkiller drugs, and of commonly found soil ions (Cl − , NO 3 − , SO 4 2− , Ca 2+ , Mg 2+ , Cu II , Fe II/III , and Ag I) were also examined. In addition, recovery of NTO was successfully performed from NTObased melt-cast formulations consisting of mixtures of TNT and NTO. The proposed method was statistically validated against a reference liquid chromatography−tandem mass spectrometry method applied to NTO standards, NTO-contaminated soil, and loam samples.

Detection of explosive residues in soil and post-blast debris is an important issue in sensor design for environmental and criminological purposes. An easy-to-use and low-cost gold nanoparticles (AuNPs)-based colorimetric sensor was developed for the determination of nitroaromatic explosives, i.e., trinitrotoluene (TNT) and tetryl, capable of analyte detection at picomolar (pM) levels. The sensor nanoparticles were synthesized by functionalizing the negatively-charged thioglycolic acid (TGA)-modified AuNPs with positively-charged (±)-trans-1,2-diaminocyclohexane (DACH) at a carefully calculated pH. The working principle of the sensor is charge-transfer (CT) interaction between the electron-rich free amino (-NH 2) group of DACH and the electrondeficient-NO 2 groups of TNT/tetryl, added to possible nanoparticle agglomerization via electrostatic interaction of TNT-Meisenheimer anions with more than one cationic DACH-modified AuNPs. The limit of detection (LOD) and limit of quantification (LOQ) of the sensor were 1.76 pM and 5.87 pM for TNT, and 1.74 pM and 5.80 pM for tetryl, respectively. TNT, tetryl and tetrytol, extracted from nitroaromatic explosive-contaminated soil sample, were determined with the proposed sensor, yielding good recoveries. The sensor could be selectively applied to various mixtures of TNT with common energetic materials such as RDX, HMX, PETN. Additionally, common soil ions (Cl-, NO 3-, SO 4 2-, K + , Mg 2+ , Ca 2+ , Cu 2+ , Fe 2+ , Fe 3+ and Al 3+) as well as detergents, sugar, sweeteners, acetylsalicylic acid (aspirin), caffeine and paracetamol-based painkiller drugs, which may be used as camouflage materials for explosives, either had no adverse effects or removable interferences on the detection method. The developed method was statistically validated against a GC-MS literature method. ASSOCIATED CONTENT Supporting Information. Supporting information contains; (i) Preparation of solutions, (ii) Determination of TNT in complex materials.

A simple, sensitive, and nonenzymatic nanospectrophotometric method was developed for the determination of reducing sugars. The silver mirror reaction-assisted method is based on the in situ formation of silver nanoparticles in the presence of reducing sugars. All simple reducing sugars (glucose, galactose, fructose, mannose, maltose, and lactose) examined had perfectly linear regression equations. The detection limit for glucose was 40 nM. The proposed method could be selectively applied to various synthetic mixtures of reducing sugars with polyphenolic compounds, and to honey, milk, and commercial fruit juice as real samples using solid phase extraction as a clean-up process. The developed method was also statistically validated against conventional alkaline CUPRAC (cupric−neocuproine, Cu(II)−Nc) spectrophotometric method using Student's t-and F-tests.

Cannabis is an important industrial plant, in addition to its illicit drug use. Compound Δ 9-THC (Δ 9-tetrahydrocannabinol) is mainly responsible for the hallucinogenic effect on humans. The aminoalkylindole group cannabimimetics targets at the same physiological receptors to mimic the analgesic effects of Δ 9-THC. Since there is no reliable colorimetric test to detect these synthetic cannabimimetics on site, a simple colorimetric assay for (aminoalkyl)indole group-containing drugs was developed, based on the silica/sulfuric acid-catalyzed Ehrlich reaction of (aminoalkyl)indoles with p-dimethyl aminobenzaldehyde. The electrophilic substitution reaction of indoles with carbonyl compounds resulting in the formation of bis(indolyl)alkanes in an acid-catalyzed reaction has been used for the first time for their spectrophotometric determination by color change from yellow to purple/blue. The method was statistically validated against liquid chromatography tandem mass spectrometry, and applied to certain (aminoalkyl)indole derivatives, with 0.5-2.5 μg mL-1 detection limits

Although the use of once widely applied selective herbicide, 4,6-dinitro-o-cresol (DNOC), was cancelled by US-EPA in 1987, it is still found in soil and water due to its slow degradation in the environment. Since solid phase extraction-spectrophotometry combinations are much simpler and cheaper than chromatography/MS based methods and most routine laboratories lack such sophisticated instrumentation, it is desirable to establish novel sensitive, well-established, and field-applicable spectrophotometric methods for the rapid assay of DNOC in water and soil. For this purpose, two distinct spectrophotometric methods utilizing the periodate and copper(II)-neocuproine (Nc) reagents have been developed following Zn/HCl reduction of the pesticide in a microwave oven for 15 s, and validated for DNOC determination at mg L −1 level. The LOD values were 1.6 and 0.2 mg L −1 for periodate and Cu(II)-Nc methods, respectively. Statistical comparison of the developed methods was made with the aid of high performance liquid chromatography (HPLC) equipped with a C 18 (5 m), 250 mm× 4.6 mm ID reversed phase column in conjunction with a UV (264 nm) detector, and a methanol (HPLC grade) +0.1% glacial acetic acid mixture mobile phase. Both spectrophotometric methods were directly applicable to soil since they were not interfered with common soil cations and anions, together with some pesticides. These methods were applied to real samples such as synthetically contaminated montmorillonite and lemon juice, and overall recovery efficiencies at the order of 95% or greater were achieved in the devised adsorption/elution procedures. An 8-hydroxyquinoline (oxine)-impregnated XAD copolymer resin stabilized with Fe(III) salt was used to preconcentrate DNOC at a concentration factor of 20 from lemon juice contaminated with 1 mg L −1 DNOC, and the analyte retained at pH 2.5 was eluted with 0.025 M methanolic NaOH. Both the devised spectrophotometric methods and the proposed preconcentration column with optimized sorption and desorption conditions are novel for DNOC assay in the natural environment.

As there are no molecular spectroscopic determination methods for the most widely used insensitive energetic materials, 2,2 ,4,4 ,6,6-hexanitrostilbene (HNS) and 3-nitro-1,2,4-triazole-5-one (NTO), in the presence of sensitive nitro-explosives, two novel spectrophotometric methods were developed. For HNS and TNT mixtures, both analytes react with dicyclohexylamine (DCHA) forming different colored chargetransfer complexes, which can be resolved by derivative spectroscopy. The spectrophotometric method for NTO measures the 416-nm absorbance of its yellow-colored Na + NTO − salt formed with NaOH. TNT, if present, is pre-extracted into IBMK as its Meisenheimer anion forming an ion-pair with the cationic surfactant cetyl pyridinium (CP +) in alkaline medium, whereas the unextracted NTO is determined in the aqueous phase. The molar absorptivity (ε, L mol −1 cm −1) and limit of quantification (LOQ, mg L −1) are as follows: for HNS, ε = 2.75 × 10 4 and LOQ = 0.48 (in admixture with TNT); for NTO, ε = 6.83 × 10 3 and LOQ = 0.73. These methods were not affected from nitramines and nitrate esters in synthetic mixtures or composite explosives. The developed methods were statistically validated against HPLC, and the existing chromatographic method was modified so as to enable NTO determination in the presence of TNT. These simple, low-cost, and versatile methods can be used in criminology, remediation/monitoring of contaminated sites, and kinetic stability modeling of munitions containing desensitized energetic materials.