The forced degradation study of lidocaine HCl was carried out according to the ICH guideline Q1A (R2). The degradation conditions were assessed to be hydrolysis, oxidation, photolysis and dry heat during 24 h, 48 h and 72 h and then the samples were investigated by GC-FID method and nuclear magnetic resonance (NMR) spectroscopy. According to these results, the degradation products were not observed in all reaction conditions during the 72 h period. Only spectral changes in the 1H and 13C-NMR spectrum were observed in hydrogen peroxide and acid degradation. As a result of this degradation, n-oxide was formed. After acid-induced degradation with HCl, the secondary amine salt was formed. Furthermore, trifluoroacetic acid (TFA) was used as the acidic media, and the decomposition products were observed. A simple and reliable gas chromatography method with flame ionization detection (GC-FID) was developed and validated for the determination of lidocaine HCl in pharmaceutical formulations in the form of a cream and injections. The GC-FID method can be used for a routine analysis of lidocaine HCl in pharmaceutical formulations and the proposed method, together with NMR spectroscopy, can be applied in stability studies.

Tuak, Tuak manis, and Brem are traditional beverages produced through the fermentation of specific plants on Lombok Island, Indonesia. Evaluating the alcohol content in these beverages is crucial for ensuring their halal status and safety for Muslim consumers. This research aims to determine the alcohol concentration of traditional drinks obtained from various tourist locations in Mataram City, Lombok Island, Indonesia. Alcohol levels were analyzed after simple distillation using the GC-FID method, validated through parameters such as accuracy, linearity, selectivity, limits of detection (LOD), limits of quantitation (LOQ), and recovery. The results showed an RSD value of 1.6292%, a linear regression equation of y = 1102x + 11.103, a regression coefficient (R²) of 0.9997, selectivity (Rs) > 1.5, an LOD of 0.0256%, an LOQ of 0.0854%, and a recovery rate of 102.83%. These findings demonstrate that the validation parameters are robust and suitable for determining alcohol content. The measured alcohol concentrations in the traditional beverages were as follows: Tuak contained 1.43±0.21% to 3.50±0.12%, Brem contained 1.32±0.14% to 3.10±0.10%, and Tuak manis contained 0.0004±0.0003% to 0.2361±0.0081%. Significant differences in alcohol content were observed across sampling locations (p < 0.05, one-way ANOVA). All samples of Tuak and Brem contained alcohol levels exceeding 0.5%, while Tuak manis had ethanol concentrations less than 0.5%. This information is expected to raise public awareness regarding the consumption of halal and safe traditional beverages.

In this study, a simple, rapid, and an economical method has been proposed for the extraction, preconcentration, and determination of parabens (methyl-, ethyl-, and propylparaben) in different samples based on derivatization by acetic anhydride and preconcentration using air-assisted liquid–liquid microextraction in a single step. In this method, 1, 1, 2, 2-tetrachloroethane (extraction solvent) containing mL-level of acetic anhydride (derivatization agent) is injected into aqueous sample containing parabens and picoline (catalyst). The mixture of aqueous and organic phases is withdrawn into a glass syringe and then injected into the test tube for several times till a turbid solution is obtained. After centrifuging, 1 mL of the sedimented phase is injected into gas chromatography-flame ionization detector. The effect of catalyst volume, derivatization agent volume, extraction solvent type and volume, ionic strength of the solution, pH, and numbers of extraction on the extraction efficiency is investigated. Under the optimal conditions, the enrichment factors and enhancement factors for the parabens were obtained in the ranges of 310-353 and 2,484-5,298, respectively. Limits of detection were between 0.18 and 8.5 mg L-1. The method was found to be linear over the range of 10-10,000 mg L-1 with good coefficients of determination (R2 > 0.999). The obtained extraction recoveries ranged from 69 to 107 % and precision of the method, expressed as relative standard deviation (RSD %), was within the range of 4.0-13 %. The proposed method was successfully applied for determination of parabens in different samples such as cream, toothpaste, and mouthwash.

Background: Urinary organic acids are water-soluble intermediates and end products of the metabolism of amino acids, carbohydrates, lipids, and a number of other metabolic processes. In the hereditary diseases known as organic acidurias, an enzyme or co-factor defect in a metabolic pathway leads to the accumulation and increased excretion of one or more of these acidic metabolites. Gas chromatography is the most commonly-used technology to separate and identify these metabolites. In this report the analytical conditions for the determination of methylmalonic acid using a gas chromatography/flame ionization detector (GC-FID) are studied with the aim to establish a method to analyze organic acids in human urine.Methods: Studies included the GC-FID method development, the conditions of the derivatization (trimethylsilylation) reaction, and the stability of the methylmalonic acid standard solution and trimethylsilyl derivatives during storage. Also, a systematic comparison between GC-FID and gas chromatography/mass spectrometry (GC-MS) was performed.Results: The highest resolution and sensitivity were obtained at 60oC with a 30 min reaction time. Standard solutions and derivatized samples were stable for 7 days at 4-8oC. Relative standard deviations of within-day and day-to-day assay results were less than 5%. Methylmalonic acid was detected in thirty human urine samples by the proposed GC-FID, and the results were compared with gold standard technique GC-MS. The correlation coefficient between GC-MS and GC-FID was obtained with R2=0.997.Conclusions: The developed method was applied to the quantitative analysis of methylmalonic acid in urine from hospitalized children with methylmalonic acidemia. With this method we aim to support pediatric clinics in Iran and assist in clinical diagnostics.

The oldest method for the managing of the illness is the use of medicinal plants. The use of herbal products as the first choice in self-treatment of minor conditions continues to expand rapidly across Iran. This makes the safety of herbal products an important public health issue.Pesticides are used widely in agriculture to increase the production by controlling the harmful insects and disease vectors, however it has some hazards on biological system of human especially children. The present study was designed to examine the residual amount of organophosphorus pesticides (Diazinon and Chlorpyrifos) in children herbal medicines available in the Iranian market. Five children herbal medicine liquid dosage forms were purchased from pharmacy store. They were extracted with SPME (Solid Phase Microextraction) using the PDMS-DVB fibre. Then the extracts were injected into a GC. The gas chromatograph was Younglin model YL 6100 equipped with a flame ionization detector. The column was Technokroma 60 m length, 0.53 mm internal diameter and 1.25 mm film coated. The presence and quantity of Diazinon and Chlorpyrifos were evaluated using their standard curves. Trace amounts of chlorpyrifos and diazinon were detected in a few herbal medicines. Based on European pharmacopeia, threshold limits of chlorpyrifos and diazinon residues for medicinal plant materials are 0.2 and 0.5 mg/Kg, respectively. Our analysis results showed that residue limits of these two pesticides in five children herbal medicines are ignorable.

Background and Objectives: The addition of plasticizers (mainly phthalates and adipates) makes plastic flexible and popular for packaging, storing and preserving food, water, and so on. The most widely used plasticizer in food contact applications is di-ethylhexyl phthalate (DEHP) though being suspected to have carcinogenic and estrogenic properties. The aim of this study is application of magnetic solid phase extraction as new absorbent for determination of DEHP in water samples by gas chromatography (GC).Materials and Methods: Important factors in extraction, separation and determination processes were optimized using the one-variable-at-a-time method. For optimization, all tests were performed two times.Figures of merit of the proposed method were evaluated. The amount of DEHP in some water samples was determined using the proposed method.Results: The results showed that the obtained chromatogram of extract was free of significant interference. The preservatives’ recoveries ranged from 91.6% to 102.2%. Limit of detection and limit of quantitation were 0.1 mg kg-1 and 0.3 mg L-1, respectively. Concentration of DEHP in the studied samples was in the range of N.D-2.3 mg L-1.Conclusions: The acceptable performance and reliability of the proposed method were demonstrated.Temperature and time were fount as the most effective parameters in migration of DEHP.