Adrian Patrut

The detection of plastic explosives in vapor form is extremely challenging due to the very low volatility of their primary components, such as RDX and PETN. To overcome this limitation, volatile chemical markers like 2,3-dimethyl-2,3-dinitrobutane (DMNB) are added to explosive formulations to enable indirect vapor detection. This study presents a rapid method for detecting and quantifying DMNB vapors using a handheld ion mobility spectrometer (IMS) operating near ambient temperature, ammonia-doped and equipped with a non-radioactive corona discharge ionization source. The instrument, model LCD-3.2E (Smiths Detection Ltd.), is based on a twin drift–cell time-of-flight configuration and simultaneously records ion mobility spectra in both positive and negative modes. DMNB generated distinct product ion peaks in both modes, with reduced mobility values (K₀) of 1.42 cm²V⁻¹s⁻¹ (positive) and 1.37 cm²V⁻¹s⁻¹ (negative). The method demonstrated high sensitivity, with limits of detection calculated at 1.4 ppb_v (10.2 × 10⁻³ mg m⁻³) in positive mode and 3.1 ppb_v (22.7 × 10⁻³ mg m⁻³) in negative mode. The IMS system provided rapid responses within seconds and covered a quantifiable concentration range of 5–3000 ppb_v, with saturation estimated to appear above approximately 5 ppm_v (36.6 mg m⁻³). The simultaneous dual-polarity response of the DT IMS enhances both the selectivity and reliability of identification. These findings confirm the capability of portable IMSs for fast trace vapor detection in DMNB, supporting its application in field-based screening scenarios such as luggage inspection or container interrogation, where indirect detection of plastic explosives is required.

Chlorpyrifos CPF (O,O-diethyl O-(3,5,6-trichloro-2-pyridyl) phosphorothioate), known also as Chlorpyrifos-ethyl, is one of the most utilized organophosphorus pesticides worldwide. Additionally, CPF could be used as a chemical warfare agent surrogate. Although its acute toxicity is not high, it is responsible for both a large number of intoxications and chronic, delayed neurological effects. In this work, it is reported for the first time the qualitative and quantitative response produced by CPF vapors, using a pocket-held Time-of-Flight Ion Mobility Spectrometer (ToF IMS) with a non-radioactive ionization source and ammonia doping, model LCD-3.2E (Smiths Detection Ltd.), operated near ambient temperature (below 30 °C). Spectra of CPF in positive ion mode included two distinct product ion peaks; thus, identification of CPF vapors by IMS relies on these peaks—the monomer M·NH₄⁺ with reduced ion mobility K₀ = ca. 1.76 cm² V⁻¹ s⁻¹ and the dimer M₂·NH₄⁺ with K₀ = ca. 1.47 cm² V⁻¹ s⁻¹ (where M may be assignable to CPF molecule)—and positive reactant ions (Pos RIP) have K₀ = ca. 2.25 cm² V⁻¹ s⁻¹. Excellent sensitivity, with a limit of detection LOD of 0.72 ppb_v (10.5 μg m⁻³) and a limit of quantification LOQ of 2.41 ppb_v (35.1 μg m⁻³), has been noticed; linear response was up to 100 ppb_v, while saturation occurs over ca. 1000 ppb_v (14.6 mg m⁻³). Our results demonstrate that this method provides a robust tool for both off-site and on-site detecting and quantifying CPF vapors at trace levels, which has strong implications for either industrial hygiene or forensic investigations concerning the pesticide Chlorpyrifos, as well as for monitoring of environmental contamination by organophosphorus pesticides.

The Cunene region of southern Angola, especially the area around Xangongo, hosts a large number of African baobabs, including several superlative specimens. Our research reports the investigation of the three biggest specimens from Xangongo Grove, named XG-1 (11 stems; circumference 26.34 m), XG-2 (5 stems; 22.70 m) and XG-3 (9 stems; 27.73 m), and of the largest baobab from Xangongo town, named XT-1 (7 stems; 21.02 m). Several wood samples were collected from these four baobabs mainly as cores from trunks and/or primary branches and then radiocarbon-dated by AMS. The two oldest samples were extracted from two primary branches of baobab XG-1. These have practically identical radiocarbon dates of 1822 ± 19 BP and 1822 ± 10 BP, which correspond to identical calibrated ages of 1785 ± 15 and 1785 ± 10 calendar years. The calculated age of baobab XG-1 is 2100 ± 50 years. Thus, XG-1, which is called by the locals “The biggest baobab of Africa”, becomes the oldest living African baobab with accurate dating results. The results indicate ages of 1100 years for baobab XG-2, 850 years for baobab XG-3 and 550 years for baobab XT-1.

The paper presents the AMS (accelerator mass spectrometry) radiocarbon dating investigation of the historic Derby Boab Tree from Derby, Kimberley, Australia. This well-known boab (Adansonia gregorii) is frequently considered a prison tree, where Aboriginal prisoners were temporarily incarcerated in its cavity. According to recent research, the Derby Boab Tree was not used as a prison tree. The boab has a closed ring-shaped structure, with 3 perfectly fused stems enclosing a false cavity. A number of six punctiform wood samples, of the size of a grain of sand, were collected from the cavity door wall. The radiocarbon date of the oldest dated punctiform sample was 1285 ± 21 BP, a value which corresponds to a calibrated age of 1185 ± 20 calendar years. This result indicates that the age of the Derby Boab Tree is 1250 ± 50 years. This is the first accurate dating result of a boab and demonstrates that the species is a millennial angiosperm.

The article discloses the AMS (accelerator mass spectrometry) radiocarbon dating results of the well-known African baobab of Dalkut, Dhofar Governorate, Oman. The investigation shows that the baobab has a cluster structure and is composed of 3 perfectly fused stems. Three wood samples were collected from primary branches and one sample was collected from the exterior of a stem. Eight tiny segments were extracted from the samples and dated by radiocarbon. The oldest dated sample segment, which originates from a primary branch of the southern stem, had a radiocarbon date of 590 ± 18 BP, which corresponds to a calibrated age of 685 ± 15 years. This result indicates that the southern stem of the baobab of Dalkut is 800 ± 30 years old. According to other radiocarbon dating results, the two northern stems are younger and emerged from the southern stem around 550 years ago. The tree of Dalkut is a solitary baobab. The nearest baobab is over 150 km away, to the north

The article discloses the AMS (accelerator mass spectrometry) radiocarbon dating results of the Egg baobab, a superlative Grandidier baobab (Adansonia grandidieri) from the Andomiry Forest, Atsimo-Andrefana region, Madagascar. The investigation of the baobab shows that it consists of 5 perfectly fused stems and exhibits a closed ring-shaped structure with a very large false cavity inside. The calculated overall wood volume of the Egg baobab is 450 m3. Two wood samples were collected from the exterior of the stems, out of which nine tiny segments were extracted and dated by radiocarbon. The oldest sample segment had a radiocarbon date of 921 ± 24 BP, which corresponds to a calibrated age of 840 ± 25 years. According to this value the Egg baobab is 875 ± 75 years old.

A high-resolution climate archive was reconstructed based on carbon isotope analysis and radiocarbon dating of the Chapman baobab in northeastern Botswana. The Chapman baobab, which exhibited an open ring-shaped structure composed of six stems, collapsed in January 2016 during an intense El Niño event. Two samples belonging to the oldest stems were investigated in order to obtain a proxy rainfall record, which provides insight into the precipitation regime over the last millennium, evincing centennial and decadal scale variability. The results indicate that the Medieval Warm Period was marked by relatively stable precipitation, whereas rainfall variability and drought frequency increased during the Little Ice Age. The investigated area has experienced both wetter and drier conditions in the past. The wettest conditions of the last millennium were registered before 1450 while the driest period occurred in 1835. For southern Africa, inter-annual rainfall variability is mainly associated with sea surface temperatures in the Agulhas Current core region, which determine the east–west displacement of tropical temperate troughs. Previous studies suggested that positive sea surface temperature anomalies in the Mozambique Channel led to an eastward movement of the troughs but the Chapman record demonstrates a westward displacement in the past, causing drought in northeastern South Africa and wetter conditions in the central part of southern Africa. The positive rainfall correlation with SST anomalies reversed after 1900, causing a gradual decrease in precipitation and confirming the current aridity trend for Botswana. The results contribute to a better understanding of the past climate of southern Africa for which paleoclimate reconstructions remain scarce.

The article reports the AMS (accelerator mass spectrometry) radiocarbon investigation of the historic Grand Baobab of Mahajanga. The largest African baobab of Madagascar exhibits a cluster structure, which consists of 6 fused ordinary stems and of 3 small binding stems. Two samples were collected from the largest stem and from a primary branch, out of which several tiny segments were extracted and dated by radiocarbon. The oldest dated sample segment had a radiocarbon date of 214 ± 17 BP, which corresponds to a calibrated age of 265 ± 25 calendar years. The dating results indicate that the Grand Baobab of Mahajanga is 275 ± 25 years old.

The article reports the AMS (accelerator mass spectrometry) radiocarbon dating results of the historic Emperor’s Beech (Fagul Împăratului) from Muncel, Baia de Arieş, Romania. Two wood samples were collected from the large tree, out of which four segments were extracted and analysed by AMS radiocarbon. The oldest dated sample segment had a radiocarbon date of 233 ± 18 BP, which corresponds to a calibrated age of 365 ± 5 years. This value suggests an age of 420 ± 20 years for the Emperor’s Beech. Thus, the historic beech started growing around the year 1600.

The Omusati region belongs to historic Ovamboland, an area of northern Namibia populated by tribes of the Ovambo group. Four very large African baobabs of Omusati played an important role in historic events of the area, such as the tribal wars and the Namibian War of Independence. The four historic baobabs are the Ombalantu baobab (8 stems; circumference 24.50 m), Okahao baobab (4+ stems; around 25 m), Amadhila baobab (12 stems; 25.35 m) and Sir Howard baobab (9 stems; 31.60 m). Two historic baobabs collapsed totally or partially. The stems of the Amadhila baobab toppled and died in 2021, while 3 stems of the Okahao baobab collapsed a long time ago, but are still alive. Our research aimed to determine the architecture and age of these baobabs. Three baobabs (Ombalantu, Amadhila, Sir Howard) exhibit a closed ring-shaped structure, with a false cavity inside. One baobab (Okahao) had an open ring-shaped structure, before its collapse. Several wood cores were extracted from the baobabs and investigated by radiocarbon dating. The dating results indicate ages of 770 ± 50 years for the Ombalantu baobab, 650 ± 50 years for the Okahao baobab, 1100 ± 50 years for the Amadhila baobab and 750 ± 50 years for the Sir Howard baobab.