scholarly journals PTV In Situ Derivatization of Several Acidic Herbicides Using a Newly Developed GC-MS/MS Method

2020 ◽  
Vol 71 (1) ◽  
pp. 72-76
Author(s):  
Diana Puiu ◽  
Alina Tatarus ◽  
Roxana Scutariu ◽  
Liliana Cruceru ◽  
Toma Galaon
Keyword(s):  
Environmental Samples ◽  
Environmental Water ◽  
Ionization Source ◽  
Acidic Herbicides ◽  
Paper Work ◽  
Acid Herbicides ◽  
Pyridinecarboxylic Acids ◽  
In Situ Derivatization ◽  
Methoxybenzoic Acid

The uses of herbicides increased during the last decades. Because acid herbicides can be identified in environmental samples, specific analytical methods are required. In this work a new GC-MS/MS method was developed in order to detect some pyridinecarboxylic acids (clopyralid, triclopyr and fluroxypyr) and a methoxybenzoic acid (dicamba) from environmental water samples. Because these polar analytes involve a derivatization step, a Programmed Temperature Vaporizing injector (PTV) was used to shape the derivatization conditions and to minimize the working time. This process is called in port derivatization (IPD), a relative new technique which encourages greener practices in analytical laboratory. MtBSTFA was chosen to be the most suitable silylation agent due to generation of specific derivatized analyte structures, which can be further fragmented in the EI ionization source to produce specific ions for the targeted analytes, easily detectable with high sensitivity.Few studies analyzed the derivatization of above-mentioned herbicides with MtBSTFA, while no other paper work was identified in studying the in port derivatization of these compounds. The results revealed that the developed method is sensitive and robust to obtain quantitation limits below 10 ng/L.

scholarly journals In Situ Capture RT-qPCR Method for Detection of Human Norovirus in Food and Environmental Samples

Proceedings ◽  
2020 ◽  
Vol 50 (1) ◽  
pp. 1
Author(s):  
Peng Tian
Keyword(s):  
Water Samples ◽  
Environmental Samples ◽  
Detection Rate ◽  
Environmental Water ◽  
Food Samples ◽  
Detection Rates ◽  
Viral Genomes ◽  
Tulane Virus ◽  
Viral Receptors

Human noroviruses (HuNoVs) are the major cause of non-bacterial acute gastroenteritis worldwide. RT-qPCR is a widely used method to detect HuNoVs. However, the method is unable to extract a virus from environmental samples and to discriminate between infectious and non-infectious viruses. In this study, we explored a new in situ capture RT-qPCR (ISC-RT-qPCR) methodology to estimate the infectivity of HuNoV in environmental and food samples. This assay was based on capturing encapsidated HuNoV by viral receptors, followed by in situ amplification of the captured viral genomes by RT-qPCR. We demonstrated that ISC-RT-qPCR did not capture and enable signal amplification of the heat-denatured Tulane virus (TV) and HuNoVs. Therefore, ISC-RT-qPCR provides better estimates for infectivity of HuNoV than RT-qPCT. We then utilized the ISC-RT-qPCR to detect HuNoV in environmental water samples and food samples, as compared to a conventional RT-qPCR procedure. The presence of HuNoV was examined in 36 oyster samples from retail markets using by both assays for detection. The detection rates of HuNoV in gill, digestive glands, and other tissues were 33.3%, 25%, and 19.4%, respectively, by ISC-RT-qPCR; and were 5.6%, 11.1%, and 11.1%, respectively, by RT-qPCR. ISC-RTqPCR is more sensitive than RT-qPCR for the detection of HuNoV in oysters. By contrast, the HuNoV detection rate by ISC-RTqPCR is lower for environmental samples. Of the 72 water samples that tested positive for HuNoV by RT-qPCR, only 20 (27.8%) of these tested positive by ISC-RT-qPCR, suggesting that 72.2% of RT-qPCR-positive samples were unlikely to be infectious. A better detection rate by ISC-RT-qPCR in oyster samples indicates the likelihood of infectious HuNoV that accumulated in oysters, and a lower detection rate of HuNoV in environmental water by ISC-RT-qPCR, indicating that the majority of RT-qPCR-positive samples were from non-infectious viral RNA.

scholarly journals Development of a Chip Assay and Quantitative PCR for Detecting Microcystin Synthetase E Gene Expression

2010 ◽  
Vol 76 (12) ◽  
pp. 3797-3805 ◽  
Author(s):  
Hanna Sipari ◽  
Anne Rantala-Ylinen ◽  
Jouni Jokela ◽  
Ilona Oksanen ◽  
Kaarina Sivonen
Keyword(s):  
Gene Expression ◽  
Environmental Factors ◽  
Expression Profiling ◽  
Environmental Samples ◽  
Environmental Water ◽  
Chip Assay ◽  
Quantitative Real Time Pcr ◽  
Microcystin Synthetase ◽  
Dna Analyses

ABSTRACT The chip and quantitative real-time PCR (qPCR) assays were optimized to study the expression of microcystin biosynthesis genes (mcy) with RNA samples extracted from cyanobacterial strains and environmental water samples. Both microcystin-producing Anabaena and Microcystis were identified in Lake Tuusulanjärvi samples. Microcystis transcribed the mcyE genes throughout the summer of 2006, while expression by Anabaena became evident later in August and September. Active mcyE gene expression was also detectable when microcystin concentrations were very low. Detection of Anabaena mcyE transcripts by qPCR, as well as certain cyanobacterial 16S rRNAs with the chip assay, showed slightly reduced sensitivity compared with the DNA analyses. In contrast, even groups undetectable or present in low quantities as determined by microscopy could be identified with the chip assay from DNA samples. The methods introduced add to the previously scarce repertoire of applications for mcy expression profiling in environmental samples and enable in situ studies of regulation of microcystin synthesis in response to environmental factors.

Determination of Haloacetic Acids from Aqueous Samples Collected from the Canadian Environment Using an In Situ Derivatization Technique

1998 ◽  
Vol 33 (2) ◽  
pp. 279-294 ◽  
Author(s):  
Brian F. Scott ◽  
Mehran Alaee
Keyword(s):  
Drinking Water ◽  
Trifluoroacetic Acid ◽  
Water Samples ◽  
Environmental Samples ◽  
Aqueous Samples ◽  
Selected Ion Monitoring ◽  
Drinking Water Samples ◽  
In Situ Derivatization

Abstract Determination of haloacetic acid concentrations in Canadian environmental samples were carried out using an in situ derivatization method. An existing method used to quantitate monochloroacetic acid was extended to analyze simultaneously for 2,4-difluoroanilide of fluoro-, chloro- and bromoacetic acids in aqueous samples. This method requires reduction of sample volume to 50 mL, and then reacting the concentrate with 2,4-difluoroaniline using dicyclohexyl-carboiimide as catalyst in ethyl acetate to produce the acid anilide. Quantitation utilizes gas chromatography with mass selective detector in the selected ion monitoring mode. The response at m/z 129 was used to quantitate the mono-substituted acids and, with the exception of trifluoroacetic acid, the di- and tri-substituted acids were quantitated using m/z 156. Quantitation of trifluoroacetic acid utilized m/z 225. The ubiquitous nature of these compounds required analyzing a blank with each sample as traces of the haloacids were found in the solvent and chemicals used in the method. All nine anilides were synthesized with the response from standard solutions used for quantitation. Environmental samples from 14 locations were analyzed and these included lake water (replicates), rain, snow, groundwater and drinking water samples. With the exception of one groundwater sample, mono- and dichloroacetic acids were found in all samples at concentrations in the range of 0.02 to 8 µg/L. Also mono- and trifluoroacetic acid were found in 9 of 14 and 7 of 14 of the samples, respectively (0.004 to 0.600 µg/L). Monobromoacetic acid was found mainly in the drinking water samples at 4 µg/L. The dibromoacetic acid was detected in snow and drinking water samples, and trichloro- and difluoroacetic acids were detected in only a few samples. Tribromoacetic acid was not detected in any of the samples.

scholarly journals Lower Recovery of Nontuberculous Mycobacteria from Outdoor Hawai’i Environmental Water Biofilms Compared to Indoor Samples

2021 ◽  
Vol 9 (2) ◽  
pp. 224
Author(s):  
Ravleen Virdi ◽  
Melissa E. Lowe ◽  
Grant J. Norton ◽  
Stephanie N. Dawrs ◽  
Nabeeh A. Hasan ◽  
...  
Keyword(s):  
Pulmonary Disease ◽  
Environmental Samples ◽  
Nontuberculous Mycobacteria ◽  
Phylogenetic Analyses ◽  
Environmental Water ◽  
Rpob Gene ◽  
The United States ◽  
Indoor Environments ◽  
Respiratory Specimens ◽  
Rpob Sequence

Nontuberculous mycobacteria (NTM) are environmental organisms that can cause opportunistic pulmonary disease with species diversity showing significant regional variation. In the United States, Hawai’i shows the highest rate of NTM pulmonary disease. The need for improved understanding of NTM reservoirs led us to identify NTM from patient respiratory specimens and compare NTM diversity between outdoor and indoor locations in Hawai’i. A total of 545 water biofilm samples were collected from 357 unique locations across Kaua’i (n = 51), O’ahu (n = 202), Maui (n = 159), and Hawai’i Island (n = 133) and divided into outdoor (n = 179) or indoor (n = 366) categories. rpoB sequence analysis was used to determine NTM species and predictive modeling applied to develop NTM risk maps based on geographic characteristics between environments. M. chimaera was frequently identified from respiratory and environmental samples followed by M. chelonae and M. abscessus; yet significantly less NTM were consistently recovered from outdoor compared to indoor biofilms, as exemplified by showerhead biofilm samples. While the frequency of M. chimaera recovery was comparable between outdoor and indoor showerhead biofilms, phylogenetic analyses demonstrate similar rpoB gene sequences between all showerhead and respiratory M. chimaera isolates, supporting outdoor and indoor environments as possible sources for pulmonary M. chimaera infections.

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