Identification of the nitroaromatic explosives in post-blast samples by online solid phase extraction using molecularly imprinted silica sorbent coupled with reversed-phase chromatography.

In a previous work, a molecularly imprinted silica (MIS) sorbent was synthesized for the selective extraction of nitroaromatic explosives from real samples. This MIS packed in a cartridge was used for an off-line solid phase extraction procedure mainly based on hydrophobic and π-π interactions. In this work, the MIS was packed in a precolumn to be connected online with a reversed-phase LC system and a diode array detector.

Application of a new capillary electrophoretic method for the determination of carbohydrates in forensic, pharmaceutical, and beverage samples.

A new capillary electrophoresis method dedicated to the analysis of neutral underivatized carbohydrates was recently developed by our group. It involved a background electrolyte composed of 98 mM NaOH and 120 mM NaCl, and direct UV detection via the formation of an absorbing intermediate in the detection window by photooxidation. This article focuses on the validation of this method for the determination of fructose, glucose, lactose, and sucrose in forensic, pharmaceutical, and beverage samples.

On the use of response surface strategy to elucidate the electrophoretic migration of carbohydrates and optimize their separation.

This paper focuses on the optimization with a design of experiments of a new CE method for the simultaneous separation of four carbohydrates of interest (fructose, glucose, lactose, and sucrose) and five potentially interfering carbohydrates (ribose, xylose, maltose, mannose, and galactose) with a highly alkaline separation electrolyte for subsequent applications to food, beverage, forensic, or pharmaceutical samples. First, the factors that potentially affect the carbohydrate migration were identified: NaOH concentration in the separation electrolyte, separation temperature, and separation electrolyte conductivity. A central composite design was then carried out to determine and model the effects of these three factors on normalized migration times and separation efficiency.

New avenue for mid-UV-range detection of underivatized carbohydrates and amino acids in capillary electrophoresis.

Capillary electrophoresis (CE) appeared as an interesting alternative to chromatographic methods for carbohydrate analysis, but it can be difficult to implement, because of the lack of easily ionizable functions and chromophore groups. Recently, a promising method was proposed by Rovio et al. for the CE separation under extremely high alkaline conditions of neutral carbohydrates under their alcoholate form and their direct UV detection [Rovio et al.

Capillary electrophoresis analysis of inorganic cations in post-blast residue extracts applying a guanidinium-based electrolyte and bilayer-coated capillaries.

A new CE method was developed for the identification and quantitation of inorganic cations in post-blast residues. The simultaneous analysis in 20 min total runtime of eight cations in post-blast residues (ammonium, potassium, monomethylammonium, calcium, sodium, magnesium, strontium), plus lithium cation as the internal reference, was carried out with a BGE involving a non-CMR (carcinogenic, mutagenic, and harmful to reproduction) chromophore (guanidinium cation) and a double-layer modified capillary (hexadimethrine bromide/polyvinylsulfonate). A study of UV detection conditions using guanidinium ion as the probe led us to set the analysis and reference wavelengths and their associated bandwidths as well as the probe concentration fixed at 15 mM.

Selective extraction of nitroaromatic explosives by using molecularly imprinted silica sorbents.

Two molecularly imprinted silicas (MISs) were synthesized and used as selective sorbents for the extraction of nitroaromatic explosives in post-blast samples. The synthesis of the MISs was carried out with phenyltrimethoxysilane as monomer, 2,4-dinitrotoluene (2,4-DNT) as template and triethoxysilane as cross-linker by a sol-gel approach in two molar ratios: 1/4/20 and 1/4/30 (template/monomer/cross-linker). Non-imprinted silica sorbents were also prepared following the same procedures without introducing the template.

Simultaneous capillary electrophoretic analysis of inorganic anions and cations in post-blast extracts of acid-aluminum mixtures.

Bursts resulting from the chemical reaction between hydrochloric or nitric acid with aluminum foils are very often committed by the young delinquency in western countries because of its easiness of achievement. A fast, simple, selective, and cost-effective method allowing the simultaneous detection of chloride and nitrate anions and aluminum(III) was thus required. This article focused on the development and validation of a CE method using a BGE containing 2,6-pyridinedicarboxylic acid (PDC) acting as both an anionic chromophore and as an aluminum(III) complexing agent.

Identification and determination of inorganic anions in real extracts from pre- and post-blast residues by capillary electrophoresis.

Fast, selective, and sensitive analysis of inorganic anions is compulsory for the identification of explosives in post-blast or environmental samples. For the last twenty years, capillary electrophoresis (CE) has become a valuable alternative to ion chromatography (IC) for the analysis of inorganic-based explosives because of its low running costs and its simplicity of use. This article focuses on the development and validation of a CE method for the simultaneous analysis of 10 anions (chloride, nitrite, nitrate, thiosulphate, perchlorate, chlorate, thiocyanate, carbonate, sulphate, and phosphate) which can be found in post-blast residues, plus for the first time azide anion, possibly present in the composition of detonators, and the internal standard (formate) in 20 min total runtime.

Development of imprinted materials for the selective extraction of nitroaromatic explosives.

Molecularly imprinted sorbents were synthesized and used as selective extraction sorbents for the analysis of nitroaromatic explosives. Their synthesis by radical polymerization using organic monomers and by sol-gel approach using organosilanes was considered to develop a selective sorbent. The sol-gel approach with phenyltrimethoxysilane (PTMS) as monomer and 2,4-dinitrotoluene (2,4-DNT) as template gave the most promising results.