DB-5 Column Research Articles

Quantitative estimation of ethanol content in eribulin mesylate injection using headspace gas chromatographic with flame ionization detector [HS-GC-FID

A specific HS-GC method has been developed, optimized, and validated for the quantitative estimation of ethanol content in eribulin mesylate injection. Chromatographic separation was achieved on DB-624 column (30 m x 0.32 mm, 1.8 μm), consisting of 6% cyanopropyl and 94% polydimethylsiloxane as stationary phase and passing nitrogen carrier gas. The performance of the method was assessed by evaluating the specificity, linearity, precision, and accuracy of experiments. The correlation coefficient value of the linearity experiment was 0.9999. The average recoveries for the accuracy were in the range of 98.7 to 102.4%. The results proved that the method is suitable for the quantitative estimation of ethanol content in eribulin mesylate injection.

A new direct extraction by gas-chromatography with flame ionization detector coupled to head space method for the determination of alcohol content of high matrix wine products

Detection, identification, and quantitation of alcohol in any matrix rich medium is a common practice although sample preparation is inevitable and time consuming. A sensitive, precise and ultimately wide range method for detection, identification and quantification of main content/residual/impurity alcohols without any matrix interference that can be used for production phase quality control, pharmaceutical and/or bio-technological refinement or toxicological evaluation and for forensics is always needed. Even for quality control also for toxicological considerations, ethanol (EtOH) and very similar compound methanol has to be detected and identified definitely becomes vital. However, with the fermented products, the matrix becomes a challenging process, makes the methods inefficient or more extraction methods have to be implanted. Here we propose a new simple and reliable direct extraction method has been developed for the determination of alcohol content of high matrix wine products using the gas-chromatography with flame ionization detector coupled to head space. The method was developed with a rich and complex component mixture of fermented alcoholic beverages (wine) with very high matrix effects. Isopropanol (IPA) was preferred as an internal standard, and Triton X-100 (TX-100) was used as diluting solution in this method. The amount of TX-100, extraction temperature, and the total volume of solution in head space vial (20 mL) were optimized. 2.5% TX-100, 80 °C extraction temperature, and 2.0 ml of total volume were used as optimum condition. Stationary phase was the fused silica, Agilent J&W DB-624 column (30 m x 320 m x 1.8 m) and Helium was used as a mobile phase. GC oven temperature programme was 40C (5 min), 5C/min ramp to 60C (0 min) and 30C/min to 150C (1 min). Performance of the method was assessed by evaluating the recovery, accuracy, precision, linearity, limits of detection (LOD) and limit of quantification (LOQ). Calibration curve was drawn between the concentration of 2.5% to 15.0% EtOH (y = 1.572x – 0.702, R² = 0.9960, y; the ratio of peak area of EtOH to IPA, x: EtOH%). The slopes of standard addition and external calibration curve were statistically same. Recovery of the method was 97.5 ± 3.5 for tree different concentrations and the precision was %5.8 (n= 11). LOD and LOQ were calculated as 0.80% and 2.5%, respectively. The proposed method has a potential for application into the industry and academia with determination of the alcohol content/residual/impurity and also check the quality and content of the fermented medium without the effect of matrix.

METHOD DEVELOPMENT AND VALIDATION OF DIMETHYL SULPHATE CONTENT IN ESOMEPRAZOLE MAGNESIUM DRUG SUBSTANCE BY GC-MS

Dimethyl sulfate is universally used as an alkylating, sulfating and sulfonating agent in organic synthesis; hence it is one of the probable impurities during the synthesis of the esomeprazole magnesium. As per ICH M7, it is genotoxic and mutagenic, so it needs to be controlled as per the acceptable intake of dimethyl sulfate and daily sample dosage. This method validation can be achieved by the hyphenated technique of gas chromatography with mass spectroscopy, which is used to develop the dimethyl sulfate impurity in esomeprazole magnesium drug substance containing salt. The method is achieved with a DB-1 column with electron impact ionization source in sim mode ion under electronic pneumatic pressure control and deliberate oven ramp programming temperature was used. A dissolved, extracted and auto-injection sample was implemented for sample introduction in a splitless mode. Dichloromethane and 2N NaOH was used as a diluent. The calibration curve showed good linearity over the 1.69 to 8.40 ppm (limit: 5.56 ppm) and its correlation coefficient was >0.999. A limit of detection 0.50 ppm and limit of quantitation 1.69 ppm was achieved when the samples were prepared at 50 mg/mL. While recovery proved to be 106.8 to 113.5%, hence it signified the matrix effect.

Particle Size Regulation of Single-Crystalline Covalent Organic Frameworks for High Performance of Gas Chromatography.

Although polycrystalline covalent organic frameworks (PCOFs) have already shown great potential as stationary phases for chromatography, irregular shape and size distribution of PCOFs make regulation of particle size of PCOFs for high separation performance impossible, which is accessible by the application of single-crystalline COFs (SCOFs). Herein, we showed preparation of three-dimensional SCOF (SCOF-303) bonded capillaries (SCOF-303-capillary) with different particle sizes (about 0.4-1.6 μm) and further investigated gas chromatographic separation ability of these SCOF-303-capillaries for isomers of xylene, dichlorobenzene, and pinene. It was found resolution and column efficiency of SCOF-303-capillaries for isomers decreased with the increase in particle size, mainly resulting from the weaker size-exclusion effect and higher mass transfer resistance of the larger particle size of flexible SCOF-303. The obtained SCOF-303-capillary (particle size of ∼0.4 μm) offered baseline separation of xylene isomers with the high resolution of 2.26-3.52, great efficiency of 7879 plates m-1 for p-xylene, better than PCOF-303-capillary, and commercial DB-5 and HP-FFAP capillary columns as well as many reported capillaries. This work not only shows the great potential of SCOFs for gas chromatography but also provides the theoretical direction for the design of the efficient COF based stationary phase by adjusting the particle sizes.

Development and validation of determination of genotoxic impurity Bromoethane in Vigabatrin drug substance using head space gas chromatographic method [HS-GC

A specific HS-GC method has been developed, optimized, and validated for the determination of genotoxic impurity Bromoethane in Vigabatrin (VGB) drug substance. Chromatographic separation of genotoxic Bromoethane impurity was achieved on DB-1 column (30 m × 0.53 mm, 5.0 μm), consists of 100% dimethyl polysiloxane as stationary phase and passing nitrogen carrier gas. The performance of the method was assessed by evaluating the specificity, linearity, sensitivity, precision, and accuracy experiments. The established limit of detection and limit of quantification values for the genotoxic impurity was in the range of 3.57–10.80 μg/mL. The correlation coefficient value of the linearity experiment was 0.9880. The average recoveries for the accuracy were in the range of 95.3–106.8%. The results proved that the method is suitable for the determination of Bromoethane content in Vigabatrin.

HS-GC Method Development and Validation for the Estimation of Class-2 Residual Solvents in Ivabradine

A simple, rapid, accurate method for simultaneous estimation of residual solvents like Dichloromethane, Tetrahydrofuran, Toluene and Xylene in Ivabradine was performed by Head space - Gas chromatography. The residual solvents were separated using a 30 m long DB-624 column with an inner diameter of 0.53 mm and a film thickness of 3.0 m, with a flow rate of 1.2 ml/min and a run period of 12 minutes, using Nitrogen as the carrier gas and Dimethyl Sulphoxide as the solvent. All the head space parameters were maintained to achieve a good separation by maintaining temperature of 95°C -105°C and suitable pressure. Analytical method was also developed by performing various trails by changing various parameters such as chromatographic conditions and head space parameters and an optimized chromatogram was obtained by showing high resolution and accurate peaks. Validation process was carried by using ICH guidelines. All parameters were carried by procedures and results were within limits as per guidelines. Validation parameters such as linearity, precision, accuracy, ruggedness, robustness, LOD, LOQ, Specificity and system suitability were performed and the proposed was said to be more precise, specific, rapid and accurate. The percentage recoveries and peak response of dichloromethane, tetrahydrofuran, toluene and xylene were with range of 90-110% and NMT 15.

Phytochemical Screening and Characterization of Agarwood (Aquilaria malaccensis) Chips Wood Grade as Incense Headspace Volatile Compounds by GC-MS.Ms.Q.TOF, SPME

AbstractAgarwood (Aquilaria malaccensis) is an Asian tree traditionally used for many medicinal purposes, its oil constituents and inhaled vapor has sedative, antidepressant and anxiolytic activities. Gas Chromatography and quadruple time of flight –mass spectrometry (GC.MS.MS/Q.TOF) in the MS-MS mode has been used in screening and identification of multiple compounds of three different grade of agarwood chipwood, using DB-1 column which led to identification of 96 compounds while the majority of the compounds about 500 compounds remain UN knowing to the difficulties of confirming or rejecting them . The generated results were so complicated and very difficult to be interpreted for the presence of isomers with similar matched spectrums; the absence of official standard references for these compounds make the judgment of confirming the identified compounds more complicated and very hard to absolute identification to be assessed. The compounds were extracted by applying a solvent less technique; trapping incense and volatile headspace. The total Ion chromatogram detected compounds are distributed among different array over the chemical families among monoterpenes, sesquiterpenes, hydrocarbons, oxygenated monoterpenes, sesquiterpenes, norterpenoids and diterpenoids ,short chain glycols, carboxylic acids and others. The flowing compounds are the major terpene, sesquiterpene and oxygenated sesquiterpenoid found in all grades of A. malaccensis chipswood under investigation, furthermore; the study represented that the characterization of compounds from agarwood chips wood is highly possible through incense volatile sample.

Phytochemical Characterization of Extracts from Fagraea Fragrans and Juglans Regia by GC-MS Analysis

Fagraea fragrans and Juglans regia have several therapeutic applications. The present study aimed to analyze the phytochemical compositions of a methanolic crude extract from the stem bark of F. fragrans and an oily liquid from a chloroform extract of seeds of J. regia. Approximately, 220 g of methanolic crude extract (yield = ca. 5%) was obtained from the stem bark of F. fragrans from hot-solvent extraction, and approximately, 45 g of chloroform oily liquid (yield = ca. 1.5%) was obtained from the seeds of J. regia by maceration technique. The phytochemical compositions of these two extracts were analyzed separately by injecting an aliquot of 1.0 μL solution of each extract prepared in hexane to a GC-MS instrument fitted with a DB-5 column of the dimension 50 m × 0.25 mm, i.d., 0.25 μm film thickness. The presence of fourteen components, including fragrant aldehydes and bioactive sterols, was identified in the methanolic crude extract and the presence of eight components, including fatty acids, fatty esters, and γ-tocopherol, was identified in the chloroform oily liquid. For the first time, we report the presence of γ-tocopherol (3.46%), n-hexanoic acid (1.26%), ethyl hexadecanoate (4.70%), ethyl oleate (6.59%), and a high content of ethyl linoleate (29.93%) in this chloroform oily liquid. From this study, we concluded that F. fragrans and J. regia have bioactive compounds of pharmaceutical importance. Therefore, these compounds can be extracted from these plants for therapeutic applications.

A Direct Standard Headspace Method for the Determination of Chloroacetic Acid and Dichloroacetic Acid in Armodafinil Drug Substance by GC-MS

A selective GC-MS method was developed and evaluated for the determination of genotoxic impurities Chloroacetic acid (Cl-AcOH) and Dichloroacetic acid (DCl-AcOH) in Armodafinil ( AMD) drug substance. Chromatographic separation of Cl-AcOH and DCl-AcOH was achieved on DB-624 column (30 m x 0.32 mm, 1.8 µm), which contains 6% cyanopropylphenyl and 94% dimethylpolysiloxane stationary phase by helium carrier gas. Mass fragment m/z 59 was selected for the quantification of both Cl-AcOH and DCl-AcOH impurities. Further, mass fragments m/z=108 was selected for Cl-AcOH and m/z=83 was selected for DCl-AcOH as qualifier ion. The performance of the method was assessed by evaluating the specificity, linearity, sensitivity, precision and accuracy experiments. The limits of detection (LOD) and limits of quantification (LOQ) values for Cl-AcOH were 0.00003 µg mL−1, 0.00009 µg mL−1 and for DCl-AcOH analyte were 0.00003 µg mL−1 and 0.00009 µg mL−1 respectively. The correlation coefficient values of linearity experiment were 0.9929 for Cl-AcOH, 0.9908 for DCl-AcOH. The average recovery for Cl-AcOH was in the range of 104.7% to 111.4% and for DCl-AcOH was in the range of 108.2% to 111.7%. The results proved that the method is suitable for the determination of Cl-AcOH and DCl-AcOH contents in Armodafinil drug substance and method can be successfully applied in the quality control analysis.

QUANTITATIVE DETERMINATION OF RESIDUAL SOLVENTS IN PALONOSETRON API BY HS-GC METHOD

Objectives: Palonosetron is an antidote to 5-HT3 in the prevention and treatment of chemotherapy-induced nausea and vomiting (CINV). The presence of residual solvents in pharmaceutical drug substances or products, as well as excipients, can have a detrimental effect on the product’s quality and stability. These substances must be evaluated for safety and efficacy. The primary purpose of this work is to establish a method for validating and quantifying residual solvents in palonosetron API using Head Space Gas Chromatography (HS-GC). Methods: In the proposed HS-GC technique for the quantifying residual solvents - ethanol, acetone, methanol, acetonitrile, and isopropyl alcohol (IPA) in Palonosetron API, the headspace equilibrium was achieved at 100°C and analyzed by DB-624 column (30 m × 0.24 mm, 1.8 μm) with injector and detector temperature set at 200°C and 230°C respectively. The dissolving solvent was dimethyl sulfoxide (DMSO). After the initial holding time of 5mins, the temperature was increased to 120°C from 40°C in 20mins at a rate of 10°C/min using a flow rate of 10 ml/min and a split ratio of 1:25 with nitrogen as carrier gas. The approach created has been validated and quantified as per International Conference on Harmonization’s (ICH) guidelines. Results: All the results obtained were within the ICH specified limits. The validation results for repeatability studies (%RSD values) were found to be <10; recovery studies values were in the range of 90–110% and for the selected linearity range 25–150 μg/ml the correlation coefficients(γ2) for all the solvents were observed to be >0.99. Conclusion: A sensitive, simple, precise, and economic HS-GC method with Flame Ionization Detector (FID) was developed and validated to quantitatively determine the residual solvents in Palonosetron API.

ESTIMATION OF RESIDUAL SOLVENTS IN NETUPITANT API BY HEADSPACE GAS CHROMATOGRAPHY

Objective: Residual solvents are undesirable components present in Active Pharmaceutical Ingredients (API), excipients, or drug products. To meet the specific quality-based requirements, the presence of these solvents in pharmaceutical products should be monitored to ensure their safety. The main objective of this work is to develop a new method for the determination of residual solvents in netupitant API by an HS-GC method with an FID detector. Methods: An automated headspace GC method has been developed and validated for the estimation of the residual solvents-N-methyl pyrrolidine, xylene, toluene, and N, N Dimethylacetamide in netupitant API. The samples were dissolved in dimethyl sulfoxide and the equilibrium headspace gas was formed at 80 ᵒC, which was analyzed using a DB-624 column (30m*0.53 mm, 3.00 µm) with an injector and detector temperature set at 160 ᵒC and 230 ᵒC, respectively. The initial oven temperature was set at 60 ᵒC for 5 min and programmed at a rate of 10 ᵒC/min to the final temperature of 150 ᵒC, with a hold time of 5 min by maintaining the flow rate of 4.0 ml/min with a split ratio of 1:10, and total run time of 20 min. Nitrogen was used as carrier gas. The method developed was validated as per International Conference for Harmonization (ICH) guidelines for repeatability, linearity, range, ruggedness, detection limit, quantification limit, and recovery studies. Results: The linearity range selected was 50-350µg/ml and the correlation coefficient(γ2) values for all the solvents were found to be>0.99; recovery studies values were in a range of 90-110% and %RSD values were also found to be not more than 10 for the solvents. Conclusion: A novel, accurate, sensitive, and simple method was described for estimating residual solvents in Netupitant API by Headspace Gas Chromatography (HS-GC) coupled with a Flame Ionization Detector (FID). Excellent results have been observed for all the validated parameters with good peak resolution and lesser retention times.

Determination of Impurities in Perampanel Bulk Drugs by High- Performance Liquid Chromatography and Gas Chromatography

Background: High-performance liquid chromatography (HPLC) method has been used to detect related impurities of perampanel. However, the detection of impurities is incomplete, and the limits of quantification and detection are high. A sensitive, reliable method is in badly to be developed and applied for impurity detection of perampanel bulk drug. Objective: Methodologies utilising HPLC and gas chromatography (GC) were established and validated for quantitative determination of perampanel and its related impurities (a total of 10 impurities including 2 genotoxic impurities). Methods: The separation was achieved on a Dikma Diamonsil C18 column (250 mm × 4.6 mm, 5 μm) with the mobile phase of 0.01 mol/L potassium dihydrogen phosphate solution (A) and acetonitrile (B) in gradient elution mode. The compound 2-bromopropane was determined on an Agilent DB-624 column (0.32 mm × 30 m, 1.8 μm) by electron capture detector (μ-ECD) with split injection ratio of 1:5 and proper gradient temperature program. Result: Both HPLC and GC methods were established and validated to be sensitive, accurate and robust according to the International Council for Harmonization (ICH) guidelines. The methods developed were linear in the selected concentration range (R2≥0.9944). The average recovery of all impurities was between 92.6% and 103.3%. The possible production mechanism of impurities during the synthesis and degradation processes of perampanel bulk drug was also discussed. Five impurities were analyzed by liquid chromatography–mass spectrometry (LC-MS). Moreover, two of them were simultaneously characterized by LC-MS, IR and NMR. Conclusion: The HPLC and GC methods were developed and optimized, which could be applied for quantitative detection of the impurities, and further stability study of perampanel.

Pharmacokinetic Study of Safrole and Methyl Eugenol after Oral Administration of the Essential Oil Extracts of Asarum in Rats by GC-MS.

Asarum is a traditional medicine and has been widely used as remedies for inflammatory diseases, toothache, headache, local anesthesia, and aphthous stomatitis in China, Japan, and Korea. Our previous research found that safrole and methyl eugenol were vital compounds that contribute to distinguish the different species and raw Asarum and its processed products apart. The pharmacokinetics of safrole and methyl eugenol after oral administration of Asarum extract has not been reported yet. In this study, a rapid and simple gas chromatography–mass spectroscopy (GC–MS) method that has a complete run time of only 4.5 min was developed and validated for the simultaneous determination and pharmacokinetic study of safrole and methyl eugenol in rat plasma after administration of Asarum extracts. The chromatographic separation was realized on a DB-17 column (30 m × 0.25 mm × 0.25 μm). And detection was carried out under selected ion monitoring (SIM) mode. Plasma samples were pretreated by n-hexane. The pharmacokinetic parameters provided by this study will be beneficial for further developments and clinical applications of Asarum.

Simultaneous determination of 18 chlorinated hydrocarbon organic solvents in cosmetics by gas chromatography-mass spectrometry

建立了同时测定化妆品中18种氯代烃类有机溶剂的气相色谱-质谱(GC-MS)检测方法。样品在饱和氯化钠溶液中由正十四烷振荡提取后,以Agilent J&W DB-624超高惰性毛细管柱(30 m×0.25 mm×1.4 μm)为分离色谱柱进行分析,以电子轰击(EI)源、SIM模式进行质谱监测,外标法定量。结果表明,18种化合物在19 min内完成色谱分离分析,检出限(LOD, S/N=3)和定量限(LOQ, S/N=10)分别为0.033~0.049 mg/L和0.10~0.15 mg/L, 18种氯代烃类有机溶剂在0.2~100 mg/L线性范围内线性关系良好,相关系数(R2)均不小于0.9992。以阴性样品口红(固体)和漱口水(液体)为样品基质,在不同添加水平下,18种氯代烃类有机溶剂的平均回收率分别为92.4%~103.1%和93.3%~102.4%,相对标准偏差(RSD, n=6)分别为3.1%~5.3%和2.8%~5.4%。采用该方法对115个化妆品样品进行测定,3个指甲油样品均检测出四氯乙烯,测定值为11.4~42.0 g/kg。研究建立的方法采用高沸点溶剂作为进样溶剂,取消溶剂延迟时间,使只能在溶剂延迟时间出峰的化合物得到有效色谱分离,分析时间短,且重复性好,灵敏度高,可同时检测各种化妆品中多种氯代烃类有机溶剂。该方法的建立为我国化妆品中氯代烃类有机溶剂检测标准的制订和质量安全监控提供了参考。

Determination of residual solvents in paclitaxel by headspace gas chromatography

BackgroundA simple and sensitive gas chromatographic method was developed and validated for the simultaneous determination of methanol, ethanol, acetone, isopropyl alcohol, dichloromethane, N-hexane, ethyl acetate, tetrahydrofuran, and N,N-diisopropyl ethyl amine in Paclitaxel. A chromatographic separation was done on DB-624 column, 30 m length × 0.53 mm ID, and film thickness 3 μm, using a flame ionization detector (FID) with gradient column oven temperature program. The injection was carried out in split mode, with a split ratio of 5:1. A mixture of N-methyl-2-pyrrolidinone (contains 1% piperazine) and water in the ratio of 80:20 (v/v) was selected as a diluent to obtain good sensitivity along with the recovery.ResultsThe developed gas chromatographic method offers symmetric peak shape, good resolution of more than 2.0 between the solvent peaks, and the relative standard deviation for replicate injections of all the solvents were found to be not more than 15.0% with reasonable retention time for all the solvents. The limit of detection for methanol, ethanol, acetone, isopropyl alcohol, dichloromethane, N-hexane, ethyl acetate, tetrahydrofuran, and N,N-diisopropyl ethyl amine was found to be 304.69 ppm, 497.98 ppm, 498.99 ppm, 504.49 ppm, 61.81 ppm, 30.07 ppm, 505 ppm, 73.05 ppm, and 2.09 ppm, respectively. Limit of quantitation of methanol, ethanol, acetone, isopropyl alcohol, dichloromethane, N-hexane, ethyl acetate, tetrahydrofuran, and N,N-diisopropyl ethyl amine was found to be 89.62 ppm, 146.47 ppm, 146.76 ppm, 148.38 ppm, 18.18 ppm, 8.84 ppm, 148.53 ppm, 21.49 ppm, and 0.62 ppm, respectively. Precision was found to be satisfactory. Linear in the range of LOQ to 150% level for all the solvents, and accuracy along with robustness, is performed, and acceptable results were obtained.ConclusionThe proposed method was demonstrated to be simple, sensitive, specific, linear, precise, accurate, and robust, hence can be used to determine the residual organic solvents in Paclitaxel drug substance and drug product.

IDENTIFICATION AND QUANTIFICATION OF VERAPAMIL IN BLOOD AND URINE

Purpose: To adapt and validate an HPLC method for verapamil determination in blood and urine samples. Materials/Methods: Identification of verapamil and its metabolites was made by means of gas-chromatography, using Agilent 7890B/5977A GC-MS system featuring a DB-1701 column. Quantification was done by means of liquid chromatography on Agilent 1260 series HPLC, equipped with Zorbax Extend-C18 column and both diode-array and fluorescent detection modules. Blood and urine specimens were taken from patients of the Clinic for intensive treatment of acute intoxications and toxicoallergies within the course of their treatment. Results: GC-MS identification of verapamil and its metabolites was carried out after simple liquid-liquid extraction of samples without further chemical derivatization. Adapted HPLC method for quantification require isocratic conditions and mobile phase, consisted of phosphate buffer (pH 2.7; 10 mM) containing 1.5 ml L–1 triethylamine – acetonitrile (70:30, v/v) at 20oC, flow-rate 1.0 mL/min and FLD detection (excitation: 203 nm, emission: 320 nm). The method was demonstrated to be linear within the whole region of interest (4.6-4600 ng mL–1) with excellent accuracy (101.7-102.2%) and inter-day precision (5.81%) as well as good analytical recovery (81.2%) and LOQ (7.0 ng mL–1). Conclusion: A precise and easy to use method for verapamil detection and quantification is developed. The method is applicable as a routine procedure in the Laboratory of analytical toxicology for both diagnosis clarification in cases of acute intoxications and therapeutic drug monitoring.

Gas Chromatographic and Spectrophotometric Determination of Diclofenac Sodium, Ibuprofen, and Mefenamic Acid in Urine and Blood Samples.

Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used for the treatment of acute to chronic pain. A simple, fast, and reliable gas chromatographic (GC) method with flame ionization detection has been developed for the determination of NSAIDs such as diclofenac sodium, ibuprofen, and mefenamic acid after derivatization with ethyl chloroformate. The GC conditions were optimized as elution from a DB-1 column (30 mx0.32 mm id) at column temperature 150 °C for 3 min, followed by a heating rate of 20 °C/min up to 280 °C and a hold time of 5 min. The nitrogen flow rate was 2.5 mL/min. For spectrophotometric studies, the absorbance was measured against methanol at a wavelength of 200-500 nm. The calibration curves were linear within 2-10 μg/mL with limits of detection of 0.4-0.6 μg/mL of each drug. The derivatization elution, separation, and quantitation were repeatable (n=3) with relative standard deviation (RSD) within 3.9%. The method was applied for the analysis of the drugs from pharmaceutical formulations and the results of the analysis agreed with labeled values with RSDs within 0.5-3.9%. The results were also confirmed by standard addition method. The percent recovery was calculated with spiked deproteinized human blood serum and urine samples and % recovery of the drugs was obtained within 96-98% with RSDs within 3.1%. The validated method proved its ability for the assay of NSAIDs in bulk and dosage form in a short analysis time. The method was also useful for the analysis of biological samples.

Analysis of Cannabidiol, Δ9-Tetrahydrocannabinol, and Their Acids in CBD Oil/Hemp Oil Products

Hemp products are readily available and are aggressively marketed for their health and medicinal benefits. Most consumers of these products are interested because of cannabidiol (CBD), which has taken the natural products industry by storm. The CBD and Δ⁹-tetrahydrocannabinol (Δ⁹-THC) concentrations in these products are often absent, and even where labeled, the accuracy of the label amounts is often questionable. In order to gain a better understanding of the CBD content, fifty hemp products were analyzed by gas chromatography coupled with mass spectrometry (GC-MS) for CBD, Δ⁹-THC, tetrahydrocannabinolic acid (Δ⁹-THCAA), and cannabidiolic acid (CBDA). Δ⁹-THCAA and CBDA are the natural precursors of Δ⁹-THC and CBD in the plant material. Decarboxylation to Δ⁹-THC and CBD is essential to get the total benefit of the neutral cannabinoids. Therefore, analysis for the neutral and acid cannabinoids is important to get a complete picture of the chemical profile of the products. The GC-MS method used for the analysis of these products was developed and validated. A 10-m × 0.18-mm DB-1 (0.4 μ film) column was used for the analysis. The majority of the hemp products were oils, one of the products was hemp butter, one was a concentrated hemp powder capsule, and another was a hemp extract capsule. Most of the products contained less than 0.1% CBD and less than 0.01% Δ⁹-THC. Three products contained 0.1–1% CBD, and 2 products contained 0.1–0.9% Δ⁹-THC. All of the samples appeared to be decarboxylated since the CBDA and Δ⁹-THCAA results were less than 0.001%. The developed method is simple, sensitive, and reproducible for the detection of Δ⁹-THC, Δ⁹-THCAA, CBD, and CBDA in CBD oil/hemp products.

Separation performance of p-nitro-octadecyloxy-calix[8]arene as stationary phases for capillary gas chromatography

Here we report the first example of employing p-nitro-octadecyloxy-calix[8]arene (C8A-NO2) as stationary phase for capillary gas chromatographic (GC) separations. The statically coated C8A-NO2 column provided column efficiencies of 2554 plates/m and showed moderate polarity. Its selectivity and retention behaviour were investigated by a number of mixtures of diverse analytes and their isomers. It was found that the C8A-NO2 column exhibited high resolving capability for aliphatic and aromatic analytes from apolar to polar nature, especially for positional and structural isomers. Among them, advantageous resolving capability over the commercial polysiloxane DB-1701 and DB-17 columns was obtained for chloroaniline and bromoaniline isomers. In addition, the C8A-NO2 column was applied for the determination of isomer impurities in commercial reagents of geraniol, cis-decahydronaphthalene, and trans-decahydronaphthalene.

Matricaria chamomilla L. (German chamomile) flower yield and essential oil affected by irrigation and nitrogen fertilization

Matricaria chamomilla is one of the most important medicinal herbs. The aim of this study was to investigate irrigation and N-fertilization effect on German chamomile yield and essential oil production. For the purposes of this study, field experiments were established at the Experimental Farm of the University of Thessaly, Larissa, Greece, in 2016 and 2017. The experimental design was a factorial split-plot design with main factor irrigation (I1: rainfed, I2: 100% ETo) and sub factor N-fertilization (F1: 0, F2: 80, and F3: 160 kg ha-1) with four replications. Flower yield measured by samplings at the ideal collection stage (2/3 of the rounds of tubes have been opened on the elevated flowering plant). Essential oil content was determined, using a Clevenger-type distillation apparatus and essential oil analysis by a GC-MS on a fused silica DB-5 column. Irrigation had a significant effect on yield, with irrigated treatments producing higher yield in comparison with rainfed treatments (5,250 and 2,200 kg ha-1, fresh and dry flowers, respectively). Furthermore, N-application had also a significant effect on yield, with the higher N-supply producing higher yield. The highest yield and essential oil production were found for the irrigated and fertilized treatment with the higher N-dressing (I2F3, 3,800 and 25 kg ha-1 dry flowers and essential oil yield, respectively). Moreover, it was found that the irrigated treatments produced lower amount of essential oil, while N-fertilization had a positive effect on α-bisabolol and chamazulene and a negative effect on bisabolol oxide A. Although irrigation had a negative impact on the content of essential oils, the high increase in yield led to a maximization of the essential oil production for the irrigated cultivation with maximum nitrogen fertilization. Therefore, chamomile seems to be a promising annual cultivation in Greece which can be established in areas of similar environmental conditions producing satisfactory yields.