Sensitive determination of 11-nor-9-carboxy-Δ9-tetrahydrocannabinol and complementary cannabinoids in hair using alkaline digestion and mixed-mode solid phase extraction followed by liquid-chromatography-tandem mass spectrometry.

Hair drug testing can be used for the evaluation of cannabis use with a large detection window, and is required for professional driving license granting in Brazil. A positive hair result for cannabis use requires quantification of the metabolite THC-COOH above the cutoff value of 0.2 ng/g. The achievement of such lower limit of quantification is challenging, particularly with the use of liquid chromatography coupled to triple quadrupole mass spectrometers (LC-MS/MS). In this study, a very sensitive LCMS/ MS assay for the simultaneous quantification of THC-COOH along with THC, CBD, and CBN was developed and validated. Sample preparation was based on hair hydrolysis, followed by selective ion-exchange solid-phase extraction. The extraction yield was 101.5-101.6% for THC-COOH, 92.3-97.4% for THC, 89.7-95.2% for CBN, and 104.9-121.1% for CBD. Internal standard corrected matrix effects were - 2.7 to - 1,1 for THCCOOH and - 11.5 to - 0.1% for the other analytes. The lower limit of quantification was 01 ng/g for THC-COOH and 25 ng/g for THC, CBD, and CBN. The assay fulfilled validation guidelines acceptance criteria. The measurement uncertainties were determined and the assay was ISO17025 accredited, being currently used in routine testing.

Are there feasible strategies for determining bromine and iodine in human hair using interference-free plasma based-techniques?

An effective analytical method for bromine and iodine determination in human hair using interference-free inductively coupled plasma mass spectrometry (ICP-MS) was developed. Human hair was digested based on combustion reaction to obtain compatible solutions with ICP-MS analysis. Using microwave-induced combustion (MIC), masses of human hair ranging from 50 to 300 mg were efficiently digested. Only a diluted alkaline solution (100 mmol L-1 NH4OH) was used for the absorption of both analytes, which was fully compatible with ICP-MS analysis. Using these conditions low limits of detection were obtained (LOD of 0.01 µg g-1 for Br and 0.004 µg g-1 for I). Recovery tests at two levels (50% and 100%) using a standard solution or mixtures of the sample with certified reference materials (CRMs) were carried out to evaluate the suitability of proposed method and recoveries between 94% and 102% were always obtained. Accuracy was evaluated by analysis of a human hair CRM, and the Br and I concentrations obtained by the proposed method did not differ significantly from those described in the certificate. Repeatability (RSDs ≤ 4%) and reproducibility (RSDs ≤ 7%) of the results using proposed method were always very suitable. The digests obtained using the MIC method were fully compatible with ICP-MS and the interferences currently found using conventional digestion methods were completely eliminated. Ultra-trace concentrations of Br and I were determined in human hair, demonstrating that the proposed method is a suitable strategy, and it presents several advantages compared to others published in the literature.

Validation of a SPE-LC-MS/MS method for the determination of ketamine and norketamine in micropulverized hair after a single IV dose.

A SPE-LC-MS/MS method for the determination of ketamine (KET) and norketamine (NKET) was developed and validated. Extensive pulverization (25min at 25Hz) of previously cooled samples (5min in liquid nitrogen) allowed for extraction in a phosphate buffer (pH 6) solution after 10min vortex agitation at room temperature, simplifying the coupling of the extraction to an effective mixed-mode SPE (solid phase extraction) clean-up procedure. The extraction optimization was performed with samples fortified by drug incorporation according to a published procedure involving incubation of blank matrices for 16days. The method was validated for selectivity, matrix effect, linearity, LLQ (lower limit of quantification), precision, accuracy, recovery, carryover and stability after preparation and has proven to be accurate and reliable within a range of 0.02-10ng/mg for KET and 0.04-4ng/mg for NKET, meeting proposed KET cutoffs for discrimination from chronic use. In addition, the method was sensitive enough to detect the drugs after unique small (1mg/kg) intravenous doses received by patients submitted to general anesthesia before surgical procedures. Ketamine levels varied from 0.060 to 0.111ng/mg and norketamine was positive (

Recent advances in the characterization of hair of mummies from the Chilean Andean coast.

Two pre-Hispanic mummies from the Andean coast, belonging to a corpus of 16 mummies from the San Miguel de Azapa (Arica, Chile), were radiocarbon dated and analyzed in order to replace them in their historical context and to study the conservation state of the hair fibers and the heavy metal presence. The radiocarbon dating placed both mummies in the Formative period (1700 years BC to 500 years AD). Global and elemental analyses were performed using scanning electron microscopy coupled with energy dispersive X-ray spectroscopy and using X-ray fluorescence spectroscopy. These combined techniques enabled to prove the good global conservation state of the mummies' hair and to detect iron, lead, bromide and also arsenic in some cases, in significant amounts inside the hair fibers. Fourier transformed infra-red spectroscopy seemed to prove the good conservation state of the hair surface at a structural level that is why the conservation of hair proteins at a molecular level will be investigated by a proteomics approach in future work.

High levels of Mercury and Lead detected by hair analysis in two Venezuelan environments

Mercury and Lead concentrations obtained by ICP-OAS analysis of human hair from riverside communities along the Orinoco river in the Amazon state (Venezuela) were compared with those from Caracas, Venezuela. Taking into account the characteristics of these two environments and the values of the average concentrations of Mercury and Lead, baselines were established suggesting that gold mining activity near the Orinoco river is responsible for the high levels of Mercury in hair from the Amazon state, whereas automobile activity is responsible for high levels of Lead in hair in Caracas.

Concentrações de mercúrio e chumbo obtidas pela análise ICP-OAS de amostras de cabelo humano de comunidades ribeirinhas ao longo do rio Orinoco no estado de Amazonas (Venezuela) foram comparadas com outras de Caracas, Venezuela. Levando em consideração as características desses dois ambientes e os valores das concentrações médias de mercúrio e chumbo, foram estabelecidas linhas basais que sugerem que as atividades de minério de ouro próximo ao rio Orinoco são responsáveis pelos altos conteúdos de mercúrio em cabelo no estado de Amazonas. Entretanto, a indústria automotriz é responsável pelo alto conteúdo de chumbo em cabelo em Caracas.

High levels of Mercury and Lead detected by hair analysis in two Venezuelan environments / Altos níveis de Mercúrio e Chumbo detectados pela análise de cabelo em dois ambientes venezuelanos

Mercury and Lead concentrations obtained by ICP-OAS analysis of human hair from riverside communities along the Orinoco river in the Amazon state (Venezuela) were compared with those from Caracas, Venezuela. Taking into account the characteristics of these two environments and the values of the average concentrations of Mercury and Lead, baselines were established suggesting that gold mining activity near the Orinoco river is responsible for the high levels of Mercury in hair from the Amazon state, whereas automobile activity is responsible for high levels of Lead in hair in Caracas.

Concentrações de mercúrio e chumbo obtidas pela análise ICP-OAS de amostras de cabelo humano de comunidades ribeirinhas ao longo do rio Orinoco no estado de Amazonas (Venezuela) foram comparadas com outras de Caracas, Venezuela. Levando em consideração as características desses dois ambientes e os valores das concentrações médias de mercúrio e chumbo, foram estabelecidas linhas basais que sugerem que as atividades de minério de ouro próximo ao rio Orinoco são responsáveis pelos altos conteúdos de mercúrio em cabelo no estado de Amazonas. Entretanto, a indústria automotriz é responsável pelo alto conteúdo de chumbo em cabelo em Caracas.