scholarly journals Microbes a Tool for the Remediation of Organotin Pollution Determined by Static Headspace Gas Chromatography-Mass Spectrometry

Author(s):  
Christopher Finnegan ◽  
David Ryan ◽  
Ann-Marie Enright ◽  
Guiomar Garcia-Cabellos

Tributyltin (TBT) is one of the most toxic anthropogenic compounds introduced into the marine environment. Despite its global ban in 2008, TBT is still a problem of great concern due to its high affinity for particulate matter, providing a direct and potentially persistent route of entry into benthic sediments. Bioremediation strategies may constitute an alternative approach to conventional physicochemical methods, benefiting from the microorganism’s potential to metabolize anthropogenic compounds. In this work, a simple, precise and accurate static headspace gas chromatography method was developed to investigate the ability of TBT degrading microbes in sedimentary microcosms over a period of 120 days. The proposed method was validated for linearity, repeatability, accuracy, specificity, limit of detection and limit of quantification. The method was subsequently successfully applied for the detection and quantification of TBT and degrading compounds in sediment samples on day 0, 30, 60, 90 and 120 of the experiment employing the principles of green chemistry. On day 120 the concentration of TBT remaining in the microcosms ranged between 91.91 ng/g wet wt for the least effective microbial inoculant to 52.73 ng/g wet wt for the most effective microbial inoculant from a stating concentration of 100 ng/g wet wt.

2022 ◽  
Vol 24 (1) ◽  
Author(s):  
Jinjian Zheng ◽  
Christine L. Kirkpatrick ◽  
Daniel Lee ◽  
Xinxin Han ◽  
Ana I. Martinez ◽  
...  

AbstractThe recent detection of potent carcinogenic nitrosamine impurities in several human medicines has triggered product recalls and interrupted the supply of critical medications for hundreds of millions of patients, illuminating the need for increased testing of nitrosamines in pharmaceutical products. However, the development of analytical methods for nitrosamine detection is challenging due to high sensitivity requirements, complex matrices, and the large number and variety of samples requiring testing. Herein, we report an analytical method for the analysis of a common nitrosamine, N-nitrosodimethylamine (NDMA), in pharmaceutical products using full evaporation static headspace gas chromatography with nitrogen phosphorous detection (FE-SHSGC-NPD). This method is sensitive, specific, accurate, and precise and has the potential to serve as a universal method for testing all semi-volatile nitrosamines across different drug products. Through elimination of the detrimental headspace-liquid partition, a quantitation limit of 0.25 ppb is achieved for NDMA, a significant improvement upon traditional LC-MS methods. The extraction of nitrosamines directly from solid sample not only simplifies the sample preparation procedure but also enables the method to be used for different products as is or with minor modifications, as demonstrated by the analysis of NDMA in 10+ pharmaceutical products. The in situ nitrosation that is commonly observed in GC methods for nitrosamine analysis was completely inhibited by the addition of a small volume solvent containing pyrogallol, phosphoric acid, and isopropanol. Employing simple procedures and low-cost instrumentation, this method can be implemented in any analytical laboratory for routine nitrosamine analysis, ensuring patient safety and uninterrupted supply of critical medications.


Author(s):  
Ajit Anerao ◽  
Bhushan Patil ◽  
Nitin Pradhan

Objective: Dimethyl sulfate has been highlighted as potential genotoxic and carcinogenic impurity. A sensitive Headspace gas chromatography (HS-GC) method with pre-column derivatization was developed and validated for the determination of dimethyl sulfate impurity in methoxsalen active pharmaceutical ingredient.Methods: HS-GC method on the column Agilent DB-5, 30m X 0.53 mm, film thickness 1.5 µm, with flame ionization detector (FID) was used. Derivatization reagent concentration, time of reaction and pH of the solution were optimized during method development. This analytical method was evaluated by performing method validation as per ICH guideline.Results: The proposed method was specific, linear, accurate, rugged and precise. The calibration curves showed good linearity over the concentration range of 0.5 μg/ml to 3.0 μg/ml and the correlation coefficient was 0.999. Method had very low limit of detection (LOD) and limit of quantification (LOQ) 2.0 μg/g and 5.0 μg/g respectively. Accuracy was observed within 98.1%–104.5%.Conclusion: The developed method was demonstrated to be accurate, robust and sensitive for the determination of dimethyl sulfate impurity in methoxsalen drug substance.


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