Gas Chromatographic Procedure Research Articles

Metrological assurance for the analytical control of flotation reagents based on aliphatic alkoxyamines in technological media and waste of iron ore enrichment processes

Methodological developments related to the determination of the content of cationic flotation reagents (collectors) based on aliphatic alkoxyamines (Flotigam EDA, Tomamine M-4213, Feiying: TG-928) in technological media and waste of iron ore enrichment processes are considered to ensure the analytical control of technological processes in view of a danger character of generated waste. A spectrophotometric method for determination of cationic amino-containing surfactants can be used for express- and screening analysis. The method of gas chromatography was used to increase the reliability of alkoxyamine measurement and in arbitration cases. The ranges of determinable content for the photometric method in aqueous media were 0.04 – 100 mg/dm3 (extended uncertainty from 20 to 25%) and 3 – 1000 (extended uncertainty from 22 to 30%) in solid media; whereas for gas chromatographic procedure the content ranged within 0.02 – 100 mg/dm3 (extended uncertainty from 20 to 25%) in aqueous media and from 1.0 to 1000 mg/kg (extended uncertainty from 20 to 30%) in solid media, respectively. The methods for determination of the main components, alkoxyamines, in commercial compositions of amine-containing flotation reagents are also presented. The methods have been tested in modeling flotation procedures (to optimize relevant conditions and regimes of real production), certified and included in the Federal State Information System (FSIS) «Arshin».

Nanorod coordination polymers for needle trap extraction of E-cigarettes and cigarettes smoke

Nowadays, the issue of e-cigarettes gaining popularity among never-smokers and teenagers, thus becoming an emergent public health problem. Consequently, developing methods to monitor the toxic compounds in their smoke is a lucrative object. Herein, two coordination polymers (CPs) with nanorod and microsphere morphology are proposed as extractive phases in a needle trap device (NTD). The two synthesized CPs were characterized by FT-IR, SEM, BET, EDS, XPS and TGA. The extraction efficiency of two synthesized CPs was compared for polyaromatic hydrocarbons (PAHs) and as a result, the nanorods exhibited higher extraction and desorption efficiency. The prepared NTD filled with the nanorod CP was implemented to the analysis of cigarettes and e-cigarette smoke. All the influencing parameters on PAHs analysis and gas chromatography (GC) procedure were investigated and optimized. The CP with nanorod morphology was applied to develop an NTD–GC–MS method for quantification of PAHs, as model analytes in the cigarettes and e-cigarettes smoke. The prominent extractive–phase was found to be very sensitive for the determination of PAHs with reliable figures of merit, such as acceptable linearity (0.2–750 ng/L), low limits of detection (LODs), 0.05–5 ng/L, suitable intra–day and inter–day relative standard deviations (RSD% <12 %), and long lifespan (number of uses >100 times).

Exploring the Ecological Preferences and Essential Oil Variability in Wild-Growing Populations of the Endangered Local Greek Endemic Thymus holosericeus (Lamiaceae).

Thymus holosericeus Čelak. (Lamiaceae) is a taxonomically isolated and endangered local endemic thyme species which is geographically isolated in four Ionian Islands (West Greece). The present study investigated the essential oil (EO) composition, the ecological preferences, and their correlations in three T. holosericeus wild-growing populations from Zakynthos (ΤH-Z), Cephalonia (ΤH-C) and Lefkada (ΤH-L). The variations in essential oil yield and the composition of T. holosericeus populations were evaluated using hydrodistillation, GC/MS, TLC and NMR analysis. The climatic conditions of each sample were organized and analyzed in RStudio with the raster package and in SPSS with Pearson's Canonical Correlation Analysis (CCA), respectively. The aerial parts of the plants varied in EO yields from 1.92 to 2.28% w/v. The analysis of EO constituents revealed noteworthy qualitative and quantitative inter-population variation. The composition of EOs revealed the presence of linalool (82.77%) and borneol (5.95%) as major compounds in ΤH-Z, while carvacrol (35.34%), geraniol (23.98%), linalool (14.37%), borneol (5.66%), thymol (4.27%) and p-cymene (4.08%) were the main compounds in ΤH-C and linalool (40.37%), geraniol (39.42%) and borneol (5.20%) were dominant components in ΤH-L. The results of the gas chromatography procedure have also been confirmed by 1H and 13C-NMR and TLC analysis. The ecological profile showed an average annual precipitation of 942 ± 18.33 mm and the temperature limits in which T. holosericeus seems to adapt to are 6.80± 1.08 °C 27.70 ± 0.70 °C. Regarding the examined samples, TH-C was adapted to the driest summer and coldest winter conditions, TH-Z was adapted to the lowest annual precipitation with the most complex climatic conditions, and TH-L was adapted to the highest summer temperatures with the lowest precipitation in the wettest period of the year. For each sampled population, the CCA identified the association of the samples' EOs composition with the prevailing local environmental conditions.

Analysis of the volatile monoterpene composition of citrus essential oils by photoelectron spectroscopy employing continuously monitored dynamic headspace sampling.

A new photoelectron spectroscopic method permitting a quantitative analysis of the volatile headspace of several essential oils is presented and discussed. In particular, we focus on the monoterpene compounds, which are known to be the dominant volatile components in many such oils. The photoelectron spectra of the monoterpene constituents may be effectively isolated by accepting for analysis only those electrons that accompany the production of m/z = 136 ions, and by using low photon energies that restrict cation fragmentation. The monoterpene isomers are then identified and quantified by regression modelling using a library of terpene standard spectra. An advantage of this approach is that pre-concentration of the volatile vapour is not required, and all steps are performed at ambient temperature, avoiding the possible deleterious effects (such as isomerisation/decomposition) that may sometimes arise in gas chromatographic (GC) procedures. As a proof-of-principle demonstration, three citrus oils (lemon, lime, bergamot) are analysed with this approach and the results are compared with reported GC composition profiles obtained for these oils. Potential advantages of the methodology that include multiplex detection and real-time, in situ analysis are identified and discussed. Alternative and faster experimental implementations concerning laboratory-based ionization and detection schemes are proposed and considered, as is the possibility of a straightforward extension towards simultaneous determination of enantiomeric excesses.

Could the high incidence of breast cancers in Nigerian women be related to 1,4-Dioxane in skin lightening products?

Two monstrous female health-related issues are currently engaging the attention of the global community. These are the chemical skin-lightening issue and the rising female breast cancer issue. Nigeria has the highest prevalence of chemical skin lightening practice with 77.3% of traders in Lagos using such products and one of the highest incidences of breast cancer globally of 50.5 per 100,000 women. 1,4-Dioxane, a possible contaminant in toiletries and cosmetics, is an IARC group 2B carcinogen and a potential breast carcinogen. It is generated when ethylene oxide -a known breast carcinogen is added to other chemicals during manufacturing. The skin lightening procedure is most conducive for optimal per-cutaneous absorption and inhalation of Dioxane. The research question entertained was if there is a link in the increasing prevalence of skin lightening practice and the rising breast cancer burden in Nigeria. One hundred skin lightening products procured from across Lagos, Nigeria had their listed contents scrutinized and entered onto a spreadsheet, then they were analyzed for Dioxane using Scalia’s Solid Phase Extraction gas chromatography procedure. Water (Aqua) 66%, Glycerin 60% and Tocopherol or Vitamin E 41% were found to be the most listed ingredients on the package labels, with Vitamin C 28%, Kojic acid 26%, Citric acid 22% and Carrot oil seen in 20% of products. All the analyzed samples were negative for Dioxane. The study brought to the fore the need to explore other potential breast carcinogens in skin lightening cosmetics and environmental chemicals.

GC Determination of Fluorouracil in Serum by Using Hexafluroroacetylacetone as Derivatizing Reagent.

A gas chromatographic (GC) procedure has been developed for the determination of fluorouracil (5-FU) after pre-column derivatization with hexafluoroacetylacetone. GC separation was from column DB-1 (30m×0.32mm id) and the determination was by flame-ionization detection. The derivatization conditions were optimized at pH4, heating at 90°C for 40min and extraction of the derivative was in chloroform. Using the conditions nucleobases cytosine, uracil, thymine, adenine and guanine separated completely from fluorouracil. The linear calibration range and LOD for 5-fluorouracil were 0.5-40.0 and 0.2μg/mL, respectively. The derivatization, elution and separation were repeatable in terms of retention time and peak height/peak area (n = 5) and relative standard deviations (RSD) were within 3.5%. The method was applied for the analysis of serum spiked with 5-FU with recovery of 95.5-97.5% with RSD 1.5-3.1%.

Monitoring the Persistence of Devrinol, Diazinon, and Trifluralin Residues in Soil Following Application of Organic Amendments

Pesticides have the potential mobility from the site of application to natural water resources leading to surface water quality problems. Binding pesticides to soil lead to immobilization preventing their mobility into surface water and enhancing their availability for degradation by soil microorganisms and their secreting enzymes. The impact of low-cost organic amendments used in agricultural operations on the persistence of three pesticides; devrinol, diazinon, and trifluralin in agricultural soil was investigated. Pesticide residues in sewage sludge (SS), farm compost (Comp), and no-mulch (NM) control treatment following field application were monitored at different time intervals using solvent partitioning and gas chromatographic procedure (GC). Half-life (T_1/2) values of the three pesticides in soil were determined under three farming practices to investigate how long each pesticide remains in each soil treatment. Results revealed the retention of devrinol by 30%, diazinon by 55%, and trifluralin by 80% in soil amended with SS compared to sole NM soil used as control treatment. This practice might prevent the off-site movement of pesticides. Devrinol T_1/2 value of 14.1 days was significantly (P≤ 0.05) lower in soil amended with Comp compared to SS amended soil due to its high dissipation constant (K). Diazinon residues fluctuated during the first week after spraying and started to decline, reaching a minimum value of 0.004 µg g^-1 soil at 35 days after spraying. Its T_1/2 value of 10.6 days was significantly lower in SS amended soil compared to Comp waste and control treatments (15.8 and 18.5 days, respectively). Trifluralin residues in NM soil showed a low dissipation constant and greater (T_1/2) value of 116 days. Its dissipation and degradation in soil amended with Comp and SS indicated half-life (T_1/2) values of 48.5 and 34.6 days, respectively. The low adsorptive capacity of devrinol due to its high-water solubility requires minimizing its application rates in agricultural regions to prevent environmental contamination of natural water resources.

The Proof-of-Concept: The Transformation of Naphthalene and Its Derivatives into Decalin and Its Derivatives during Thermochemical Processing of Sewage Sludge

One solution for sewage sludge (SS) management is thermochemical treatment due to torrefaction and pyrolysis with biochar production. SS biochar may contain toxic volatile organic compounds (VOCs) and polyaromatic hydrocarbons (PAHs). This study aimed to determine the process temperature’s influence on the qualitative PAHs emission from SS-biochar and the transformation of PAHs contained in SS. SS was torrefied/pyrolyzed under temperatures 200–600 °C with 1 h residence time. The headspace solid-phase microextraction (SPME) combined with gas chromatography and mass spectrometry (HS-SPME-GC-MS) analytical procedure of VOCs and PAHs emission was applied. The highest abundance of numerous VOCs was found for torrefaction ranges of temperature. The increase of temperatures to the pyrolytic range decreased the presence of VOCs and PAHs in biochar. The most common VOCs emitted from thermally processed SS were acetone, 2-methylfuran, 2-butanone, 3-metylbutanal, benzene, decalin, and acetic acid. The naphthalene present in SS converted to decalin (and other decalin derivatives), which may lead to SS biochar being considered hazardous material.

Recent Developments in the Determination of Biomarkers of Tobacco Smoke Exposure in Biological Specimens: A Review.

Environmental tobacco smoke exposure (ETS) and smoking have been described as the most prevalent factors in the development of certain diseases worldwide. According to the World Health Organization, more than 8 million people die every year due to exposure to tobacco, around 7 million due to direct ETS and the remaining due to exposure to second-hand smoke. Both active and second-hand exposure can be measured and controlled using specific biomarkers of tobacco and its derivatives, allowing the development of more efficient public health policies. Exposure to these compounds can be measured using different methods (involving for instance liquid- or gas-chromatographic procedures) in a wide range of biological specimens to estimate the type and degree of tobacco exposure. In recent years, a lot of research has been carried out using different extraction methods and different analytical equipment; this way, liquid–liquid extraction, solid-phase extraction or even miniaturized procedures have been used, followed by chromatographic analysis coupled mainly to mass spectrometric detection. Through this type of methodologies, second-hand smokers can be distinguished from active smokers, and this is also valid for e-cigarettes and vapers, among others, using their specific biomarkers. This review will focus on recent developments in the determination of tobacco smoke biomarkers, including nicotine and other tobacco alkaloids, specific nitrosamines, polycyclic aromatic hydrocarbons, etc. The methods for their detection will be discussed in detail, as well as the potential use of threshold values to distinguish between types of exposure.

Разработка методики определения потенциально опасных летучих органических соединений (трихлорэтилен и тетрахлорэтилен) в атмосферном воздухе

The article dwells on results obtained via experimental research on working out a gas chromatography procedure for determining trichloroethylene and tetrachloroethylene in ambient air. Experiments were performed on substances which had low limits of detection with gas-liquid chromatography with electron capture detection (GLC/ECD) when examined substances were absorbed from ambient air on Tenax TA sorbent. Optimal gas chromatography parameters were established with a hardware-software complex based on «Crystal-5000» gas chromatographer and use of a column from IDBPX-VOL series, 60m⋅0.32mm⋅1.8µm, under the following temperatures: column, 50–230о С; evaporator, 250о С; detector, 250о С. The developed capillary gas chromatography procedure allows determining trichloroethylene in concentrations ranging from 0.000146 to 0.00146 mg/m3, and tetrachloroethylene, from 0.000081 to 0.00081 mg/m3 with inaccuracy not exceeding 25.0%. We performed metrological assessment of the procedure and it allowed determining quality of analysis results for trichloroethylene and tetrachloroethylene; they were as follows: precision, 21.97% and 14.3%: repeatability, 4.22% and 3.38%; reproducibility, 5.66% and 4.9%. Limit of detection (LOD) for trichloroethylene and tetrachloroethylene was =0.0000038 mg/dm3 and =0.00000083 mg/dm3 accordingly. Limit of quantitative determination (LOQ) was =0.000013 mg/m3 for trichloroethylene, and = 0.0000028 mg/m3 for tetrachloroethylene. The developed procedure allowed detecting contents of the examined substances in ambient air near a construction site and a dry-cleaner’s, trichloroethylene in a range from 0.00001 mg/m3 to 0.0009 mg/m3, tetrachloroethylene, from 0.000011 mg/m3 to 0.00039 mg/m3. This unified high-sensitive and selective procedure is recommended for systemic control over potentially hazardous volatile organic compounds in ambient air as it allows providing objective and reliable hygienic assessment of chemical safety and quality of the environment and health risk assessment.

Working out a procedure for determining potentially hazardous volatile organic compounds (trichloroethylene and tetrachloroethylene) in ambient air

The article dwells on results obtained via experimental research on working out a gas chromatography procedure for determining trichloroethylene and tetrachloroethylene in ambient air. Experiments were performed on substances which had low limits of detection with gas-liquid chromatography with electron capture detection (GLC/ECD) when examined substances were absorbed from ambient air on Tenax TA sorbent. Optimal gas chromatography parameters were established with a hardware-software complex based on «Crystal-5000» gas chromatographer and use of a column from IDBPX-VOL series, 60m⋅0.32mm⋅1.8µm, under the following temperatures: column, 50–230о С; evaporator, 250о С; detector, 250о С. The developed capillary gas chromatography procedure allows determining trichloroethylene in concentrations ranging from 0.000146 to 0.00146 mg/m3, and tetrachloroethylene, from 0.000081 to 0.00081 mg/m3 with inaccuracy not exceeding 25.0%. We performed metrological assessment of the procedure and it allowed determining quality of analysis results for trichloroethylene and tetrachloroethylene; they were as follows: precision, 21.97% and 14.3%: repeatability, 4.22% and 3.38%; reproducibility, 5.66% and 4.9%. Limit of detection (LOD) for trichloroethylene and tetrachloroethylene was =0.0000038 mg/dm3 and =0.00000083 mg/dm3 accordingly. Limit of quantitative determination (LOQ) was =0.000013 mg/m3 for trichloroethylene, and = 0.0000028 mg/m3 for tetrachloroethylene. The developed procedure allowed detecting contents of the examined substances in ambient air near a construction site and a dry-cleaner’s, trichloroethylene in a range from 0.00001 mg/m3 to 0.0009 mg/m3, tetrachloroethylene, from 0.000011 mg/m3 to 0.00039 mg/m3. This unified high-sensitive and selective procedure is recommended for systemic control over potentially hazardous volatile organic compounds in ambient air as it allows providing objective and reliable hygienic assessment of chemical safety and quality of the environment and health risk assessment.

Detection of clostebol in sports: Accidental doping?

The detection of clostebol misuse in sports has been growing recently, especially in Italy, due to the ample availability of pharmaceutical formulations containing clostebol acetate (Trofodermin®) and the use of more sensitive instrumentation by the antidoping laboratories. Most of these cases have been claimed to be related to a nonconscious use of the drug or through contact with relatives or teammates using it. We have investigated, through the application of the well-known and currently used gas chromatographic mass spectrometric procedures, the likelihood of these allegations and have demonstrated that after a single transdermal administration of 5 mg of clostebol acetate and a transient contact with the application area, it is possible to generate adverse analytical findings in antidoping controls. We have reviewed the Phase I and Phase II clostebol metabolism in order to generate evidences that may help the sport authorities reviewing these cases. The main clostebol metabolite (4-chloro-androst-4-en-3α-ol-17-one, M1) generally used at the screening level as well as other three metabolites (M2-M4) are mainly excreted as glucuronides, whereas M5 (4ζ-chloro-5ζ-androstan-3β-ol-17-one) is predominantly excreted as sulfate. Neither the 5α-reductases activity (impaired by the presence of the chlorine in C4) nor specific sulfotransferases present in the skin allowed a clear distinction of the administration route. Studies with a larger number of volunteers and probably investigating another physiological fluid allowed in antidoping such as blood are needed for a deeper investigation. It is not unreasonable to establish a reporting level for M1, maybe creating some false negatives but excluding nonintentional doping scenarios.

Radiation-Induced Transformations of 2-Fluoroethanol in Aqueous Solutions

Steady-state radiolysis has been used to study the radiation-induced transformations of 2-fluoroethanol in dilute aqueous solutions as a model system for examining the autoradiolytic dehalogenation of the radiopharmaceutical drug 2-[18F]fluorodeoxyglucose ([18F]FDG). A derivatization–gas chromatography procedure for determining the fluoride anion in the presence of organofluorine compounds has been developed. It has been established that •OH and H• induced the dehalogenation of 2-fluoroethanol in aqueous solutions. Unlike bromo- and chlorohydrins, 2-fluoroethanol does not interact with $${\text{e}}_{{{\text{aq}}}}^{ - }$$ according to the dissociative attachment mechanism. It has been shown that О2 halved the radiation-chemical yield of fluoride due to the oxidation of hydroxyl-containing carbon-centered radicals of 2-fluoroethanol. The constant of unimolecular dehalogenation of the 2-fluoroethanol radical is 3.9 × 106 s−1, as calculated using the method of competing reactions.

Statistical Analysis for Comparison of the Results Obtained by Capillary Columns and Packed Columns in the Determination of Water Yield in Smoke Condensates Analyzed in Cigarettes for the 24th Asia Collaborative Study

Summary Recently, capillary columns have been widely used in the methodology for the determination of water yields in smoke condensate, even though ISO 10362-1:1999, “Cigarettes - Determination of water in smoke condensates – Part 1: Gas chromatographic method” specifies a packed gas chromatographic column. As a result of a systematic review in 2015, ISO/TC126 decided to revise the standard to include the use of capillary columns. The goal of this study was to confirm the comparability of water yields obtained from capillary column methodology to those yields from packed columns by the statistical analysis of yield data from the 24th Asia Collaborative Study which included 86 datasets submitted by 64 laboratories. After the exclusion of outliers by Cochran’s and Grubbs’ tests, the datasets were classified by GC column type and then mean water yields, and their repeatability and reproducibility were calculated for each type of column. No significant differences were observed in water yields between capillary and packed columns. Repeatability and reproducibility of water yields using capillary column were comparable to those using packed columns as described in ISO 10362-1:1999. From these results, it was confirmed that the capillary columns are an appropriate alternative to packed columns for the gas chromatographic procedure described in ISO 10362-1:1999.

Chromatographic Procedure for the Determination of Products of the Direct Synthesis of Dimethyl Ether

We developed an original gas chromatographic procedure for determining the products and reagents for the catalytic synthesis of dimethyl ether (DME) from synthesis gas, which enables the simultaneous detection of СН3ОН, DME, СО, СО2, Н2, Н2О, N2, and hydrocarbons to С6. The gas circuit includes four detectors, three packed columns, two precolumns (to prevent water and organic compounds from entering molecular sieve columns) in combination with two relief valves and two pressure regulators for the implementation of the back purging of precolumns. The system is assembled based on a Khromatek-Kristall 5000 chromatograph. The determination is carried out at a constant temperature of 140°C. The duration of analysis is not more than 12 min. Because of the presence of a flame ionization detector, it is possible to detect trace amounts of hydrocarbons, as well as ethane in the presence of large amounts of CO2.

Establishment and Validation of a Sensitive Method for the Detection of Pregabalin in Pharmacological Formulation by GC/MS Spectrometry

Background: A gas chromatography and mass spectrometry (GC/MS) procedure was developed and validated for the evaluation and quantification of pregabalin (PGN) in pharmaceutical preparations. &lt;/P&gt;&lt;P&gt; Introduction: Pregabalin is a γ-amino-n-butyric acid derivative used as an antiepileptic drug for the management of fibromyalgia, and has analgesic, anxiolytic, and anticonvulsant activities. Few studies have been reported on the determination of PGN content in pharmaceutical preparations involving gas chromatography - mass spectroscopy. Methods: Pregabalin was extracted with MSTFA/NH4F/β- mercapto-ethanol at 60°C for 30 min. The acquired derived molecule of pregabalin was identified by specific ion monitoring mode applying the analytical ions m/z 232 and 331. Propranolol was used as Internal Standard (IS). The following validation parameters were taken into consideration: precision, linearity, accuracy, stability, specificity, robustness, ruggedness, Limit Of Detection (LOD) and Limit Of Quantitation (LOQ). Results: The method was selective, precise, sensitive, linear and specific. The linearity of the method was between 3.5 and 300 ng/ml. The precise values were ≤ 3.62% of both intra- and interday validation. The LOD accurate values for Intraday and interday validation were in the range of -0. 25 -2.05%. While LOQ accurate values for intraday and interday were 1.5x10-6 and 3.5 x10-6mg/ml, respectively. Conclusion: Therefore, the developed GC-MS method was effectively implemented to identify PGN in a pharmacological preparation.

Determination of Egg Number Added to Special Pasta by Means of Cholesterol Contained in Extracted Fat Using GC-FID.

Pasta with eggs added (generally termed “special pasta” for Italian legislation) is made by adding no less than 4 eggs without shells (or no less than 200 g of liquid or lyophilized egg product) per kilogram of semolina, as provided by law. In this work, to determine the final content of eggs added to dough, an analytical procedure was developed for the rapid analysis of the cholesterol content in the finished pastas. The proposed procedure was simpler, faster, and more accurate than that of official methods of analysis based on the gravimetric determination of sterols. Moreover, the determination of the quality of fat content in the special pasta (egg pasta in this case) allowed the evaluation of its origin, avoiding possible fraud resulting from the addition of foreign fat as an alternative to fat derived from eggs. In this new gas chromatographic procedure, the internal standard squalene for the quantification of cholesterol was used because a more polar GC capillary column was used (RTX 65 TG-HT) for the separation of sterols, rather than 5% phenyl methylsilicone. The ratio between cholesterol and squalene allowed for the determination of the number of eggs added, while from analysis of the same gas chromatogram, it was also possible to evaluate the composition of triglycerides in the fat contained in the pasta, allowing discrimination of foreign fats with respect to fats contained in eggs and therefore avoiding adulteration of pasta. The same analytical procedure was applied to the determination of cholesterol content in lyophilized yolk.

Characterization of the artist's palette from the polychrome decorations of the El Bahia Palace doors (Marrakesh, Morocco)

Abstract We investigated the cedar wood doors of the Bahia Palace in Marrakesh (Morocco), which are richly decorated with geometric motifs. A gas chromatographic mass spectrometric analytical procedure (GC/MS) was used to characterize the organic binders in micro samples collected from one of the doors. In order to examine the artist's palette, X-ray fluorescence (XRF), Raman and Fourier transform infrared spectroscopy (FTIR) and high performance liquid chromatography (HPLC-DAD), were applied to samples in fragments or on cross-sections of the embedded samples. This multi analytical approach effectively identified the polychrome decoration technique, mainly based on the use of animal glue as a proteinaceous binder, and characterized the superficial varnishes. Lastly many of the different pigments used for the creation of these works of art were identified. We believe that this study contributes significantly to the knowledge of Moroccan art from a material and technological point of view.

Trace level determination of chloroacetyl chloride and degradation products by derivatization gas chromatography

A gas chromatographic procedure has been developed for the trace determination of chloroacetyl chloride (CAC) and two of its impurities: methyl chloroacetate (MCA) and chloroacetic acid (CAA). All three compounds are derivatized using piperidine in dichloroethane prior to their analysis via gas chromatography coupled with a flame ionization detection (GC-FID). Recoveries of each compound were assessed in two different pharmaceutical matrices (intermediate and final active pharmaceutical ingredient) and ranged from 75 to 125%. The limit of quantitation has been determined to be 0.10% wt/wt for CAA and 0.03% wt/wt for CAC and MCA. The linearity ranged from 0.03 to 5.00% wt/wt for CAC and MCA and from 0.10 to 5.00% wt/wt for CAA, with correlation coefficients from 0.9995 to 1.0000. Repeatability was evaluated at LOQ and at 5.00% wt/wt and was found to be between 1.4–3.0%.

The (non)sense of routinely analysing beta-hydroxybutyric acid in forensic toxicology casework

Beta-hydroxybutyric acid (BHB) is a ketone body which is generated from fatty acids as an alternative energy source when glucose is not available. Determination of this compound may be relevant in the forensic laboratory as ketoacidosis – an elevated level of ketone bodies – may contribute to the cause of death. In this study, we aimed at determining the relevance of routinely implementing BHB analysis in the forensic toxicological laboratory, as BHB analysis typically requires an additional workload. We therefore performed an unbiased retrospective analysis of BHB in 599 cases, comprising 553 blood, 232 urine and 62 vitreous humour samples. Cases with BHB concentrations above 100mg/L (in blood, urine and/or vitreous humour) were invariably associated with elevated levels of acetone, another ketone body, the detection of which is already implemented in most forensic laboratories using the gas chromatographic procedure for ethanol quantification. Our retrospective analysis did not reveal any positive case that had been missed initially and confirms that BHB analysis can be limited to acetone positive cases.