scholarly journals Method Validation for Analysis of Aroclor 1260 in Transformer Oil using Gas Chromatography – Electron Capture Detection

2019 ◽  
Vol 9 (2) ◽  
Author(s):  
J.J. Jeevanantham ◽  
D.A.T.W.K. Dissanayake ◽  
G.V.V Liyanaarachchi ◽  
M.N.A. Mubarak ◽  
W.M.A.K. Wijesinghe ◽  
...  
Keyword(s):  
Transformer Oil ◽  
Electron Capture Detection ◽  
Validation Data ◽  
Limit Of Determination ◽  
Relative Standard ◽  
The Matrix ◽  
Transformer Oils ◽  
Aroclor 1242 ◽  
Chromatographic Peaks

Since early 1980’s, the production and usage of Polychlorinated biphenyls (PCBs) have been banned throughout the world due to its carcinogenicity to humans and animals. However, due to the large half-lives of PCBs, large amounts of stocks are still available in storage. This study presents the validation data of the method developed for analysis of Aroclor 1260 in transformer oils in order to determine the concentrations for systematic disposal and destruction.The transformer oil samples were prepared according to the ASTM D 4059 with few modifications. PCBs in transformer oils were extracted with iso-octane followed by deactivated florisil cleanup and detection by GC – ECD using HP 5 GC column (30 m x 0.32 mm x 0.25 μm). The study was performed under matrix matched condition to eliminate the matrix effect that was found to be significant. The method was found linear over a wide working range from 2.5 ppm – 100 ppm with a regression coefficient of 0.994 and a lower limit of determination of 2.5ppm. Method showed satisfactory repeatability with relative standard deviation below 7% over the entire working range. Accuracy of the method was assured using spike recoveries at 5 ppm, 10 ppm and 50 ppm with 85%, 105% and 93% respectively. The selectivity of Aroclor 1260 was confirmed against Aroclor 1254 and Aroclor 1242 considering uniquely identified non – overlapping chromatographic peaks. Based on the performance characteristics, this method can be suggested as an accurate and precise methodology to analyze Aroclor 1260 present in transformer oil.

Residue Analysis of Organophosphorus and Organochlorine Pesticides in Fatty Matrices by Gas Chromatography Coupled with Electron-Capture Detection

2006 ◽  
Vol 61 (5-6) ◽  
pp. 341-346 ◽  
Author(s):  
Jae-Woo Park ◽  
A. M. Abd El-Aty ◽  
Myoung-Heon Lee ◽  
Sung-Ok Song ◽  
Jae-Han Shim
Keyword(s):  
Gas Chromatography ◽  
Electron Capture ◽  
Simple Procedure ◽  
Linear Regression Analysis ◽  
Residue Analysis ◽  
Electron Capture Detection ◽  
Relative Standard ◽  
Wide Range ◽  
Repeatability And Reproducibility

A multiresidue method for the simultaneous determination of 22 organochlorine (OCs) and organophosphorus (Ops) pesticides (including isomers and metabolites), representing a wide range of physicochemical properties, was developed in fatty matrices extracted from meat. Pesticides were extracted from samples with acetonitrile/n-hexane (v :v, 1:1). The analytical screening was performed by gas chromatography coupled with electron-capture detection (ECD). The identification of compounds was based on their retention time and on comparison of the primary and secondary ions. The optimized method was validated by determining accuracy (recovery percentages), precision (repeatability and reproducibility), and sensitivity (detection and quantitation limits) from analyses of samples fortified at 38 to 300 ng/g levels. Correlation coefficients for the 22 extracted pesticide standard curves (linear regression analysis, n = 3) ranged from 0.998 to 1.000. Recovery studies from 2 g samples fortified at 3 levels demonstrated that the GC-ECD method provides 64.4-96.0% recovery for all pesticides except 2,4′-DDE (44.6-50.4%), 4,4′-DDE (51.1-57.5%) and 2,4′-DDT (50.0-51.2%). Both repeatability and reproducibility relative standard deviation values were < 20% for all residues. Detection limits ranged from 0.31 to 1.27 ng/g and quantification limits were between 1.04 and 4.25 ng/g. The proposed analytical method may be used as a simple procedure in routine determinations of OCs and Ops in meat. It can also be applied to the determination of pesticide multi-residues in other animal products such as butter and milk.

scholarly journals Simultaneous Determination of Nitroimidazoles and Quinolones in Honey by Modified QuEChERS and LC-MS/MS Analysis

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Haiyan Lei ◽  
Jianbo Guo ◽  
Zhuo Lv ◽  
Xiaohong Zhu ◽  
Xiaofeng Xue ◽  
...  
Keyword(s):  
Recovery Rates ◽  
Inhibition Effect ◽  
Standard Curve ◽  
Modified Quechers ◽  
Relative Standard ◽  
Acacia Honey ◽  
The Matrix ◽  
Liquid Chromatography Tandem Mass ◽  
Standard Deviations

This study reports an analytical method for the determination of nitroimidazole and quinolones in honey using liquid chromatography-tandem mass spectrometry (LC-MS/MS). A modified QuEChERS methodology was used to extract the analytes and determine veterinary drugs in honey by LC-MS/MS. The linear regression was excellent at the concentration levels of 1–100 ng/mL in the solution standard curve and the matrix standard curve. The recovery rates of nitroimidazole and quinolones were 4.4% to 59.1% and 9.8% to 46.2% with relative standard deviations (RSDs) below 5.2% and the recovery rates of nitroimidazole and quinolones by the matrix standard curve ranged from 82.0% to 117.8% and 79% to 115.9% with relative standard deviations (RSDs) lower than 6.3% in acacia and jujube honey. The acacia and jujube honeys have stronger matrix inhibition effect to nitroimidazole and quinolones residue; the matrix inhibition effect of jujube honey is stronger than acacia honey. The matrix standard curve can calibrate matrix effect effectively. In this study, the detection method of antibiotics in honey can be applied to the actual sample. The results demonstrated that the modified QuEChERS method combined with LC-MS/MS is a rapid, high, sensitive method for the analysis of nitroimidazoles and quinolones residues in honey.

scholarly journals Determination of 77 Multiclass Pesticides and Their Metabolitesin Capsicum and Tomato Using GC-MS/MS and LC-MS/MS

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1837
Author(s):  
Harischandra Naik Rathod ◽  
Bheemanna Mallappa ◽  
Pallavi Malenahalli Sidramappa ◽  
Chandra Sekhara Reddy Vennapusa ◽  
Pavankumar Kamin ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Solid Phase ◽  
Graphitized Carbon Black ◽  
Limit Of Quantification ◽  
Gas And Liquid Chromatography ◽  
Relative Standard ◽  
The Matrix ◽  
Liquid Chromatography Tandem Mass ◽  
Primary Secondary Amine

A quick, sensitive, and reproducible analytical method for the determination of 77 multiclass pesticides and their metabolites in Capsicum and tomato by gas and liquid chromatography tandem mass spectrometry was standardized and validated. The limit of detection of 0.19 to 10.91 and limit of quantification of 0.63 to 36.34 µg·kg−1 for Capsicum and 0.10 to 9.55 µg·kg−1 (LOD) and 0.35 to 33.43 µg·kg−1 (LOQ) for tomato. The method involves extraction of sample with acetonitrile, purification by dispersive solid phase extraction using primary secondary amine and graphitized carbon black. The recoveries of all pesticides were in the range of 75 to 110% with a relative standard deviation of less than 20%. Similarly, the method precision was evaluated interms of repeatability (RSDr) and reproducibility (RSDwR) by spiking of mixed pesticides standards at 100 µg·kg−1 recorded anRSD of less than 20%. The matrix effect was acceptable and no significant variation was observed in both the matrices except for few pesticides. The estimated measurement uncertainty found acceptable for all the pesticides. This method found suitable for analysis of vegetable samples drawn from market and farm gates.

Simultaneous Determination of Eight New Generation Amide Insecticide Residues in Complex Matrix Agri-food by Multi-walled Carbon Nanotube Cleanup and UPLC-MS/MS

2021 ◽  
Author(s):  
Tao Lin ◽  
Xinglian Chen ◽  
Li Wang ◽  
Haixian Fang ◽  
Maoxuan Li ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Simultaneous Determination ◽  
High Performance ◽  
Rapid Determination ◽  
Complex Matrix ◽  
Limit Of Quantification ◽  
Relative Standard ◽  
The Matrix ◽  
Multi Walled Carbon Nanotubes

Abstract The simultaneous determination method of 8 amide pesticides by multi-walled carbon nanotubes (MWCNs) cleanup, combined with QuEChERS method and ultra-high performance liquid chromatography-triple quadrupole tandem mass spectrometry has been developed and successfully applied in complex matrix such as green onions, celery, leeks, citrus, lychees, avocado. The matric effect of MWCNs is optimized and compared with QuEChERS materials. The results show that MWCNs can effectively reduce the matrix effect in sample extraction. The mass spectrometry is optimized, through their chemical structure skeletons, the ESI+ and ESI- mode are simultaneously scanned in the method. The coefficient (r) is greater than 0.9990, the limit of quantification ranges from 0.03 to 0.80 μg/kg, the recovery rate ranges from 71.2% to 120%, and the relative standard deviation (RSD) ranges from 3.8% to 9.4%. The method is fast, simple, sensitive, and has good purification effect. It is suitable for the rapid determination of amide pesticides in complex matrix agri-food.

scholarly journals Determination of Insecticides in Honey by Matrix Solid-Phase Dispersion and Gas Chromatography with Nitrogen–Phosphorus Detection and Mass Spectrometric Confirmation

2002 ◽  
Vol 85 (1) ◽  
pp. 128-133 ◽  
Author(s):  
Consuelo Sánchez-Brunete ◽  
Beatriz Albero ◽  
Ester Miguel ◽  
José Luis Tadeo
Keyword(s):  
Solid Phase ◽  
Single Step ◽  
Organophosphorus Insecticides ◽  
Matrix Solid Phase Dispersion ◽  
Phase Dispersion ◽  
Relative Standard ◽  
The Matrix ◽  
Low Volume ◽  
Nitrogen Phosphorus

Abstract A multiresidue method was developed for the determination of 12 organophosphorus insecticides (diazinon, parathion methyl, fenitrothion, pirimiphosmethyl, malathion, fenthion, chlorpyrifos, quinalphos, methidathion, ethion, azinphosmethyl, coumaphos), one carbamate (pirimicarb), and one amidine (amitraz) in unifloral and multifloral honeys. The analytical procedure was based on the matrix solid-phase dispersion of honey on a mixture of Florisil and anhydrous sodium sulfate in small glass columns and subsequent extraction with a low volume of hexane–ethyl acetate (90 + 10, v/v), assisted by sonication. The insecticide residues were determined by capillary chromatography with nitrogen–phosphorus detection and confirmed by mass spectrometry. Average recoveries at the 0.05–0.5 μg/g levels were &gt;80% for organophosphorus insecticides and about 60% for the other insecticides, pirimicarb and amitraz, with relative standard deviations &lt;10%. The detection limit for the different insecticides ranged between 6 and 15 μg/kg. The main advantages of the proposed method are that extraction and cleanup are performed in a single step with a low volume of organic solvent. The method is simple, rapid, and less laborious than conventional methods. Several Spanish honeys were analyzed with the proposed method and no residues of the studied insecticides were found.

Gas-Liquid Chromatographic Determination of Total Inorganic Iodine in Milk

1977 ◽  
Vol 60 (6) ◽  
pp. 1307-1309 ◽  
Author(s):  
Hendrik J Bakker
Keyword(s):  
Liquid Chromatography ◽  
Iodine Content ◽  
Chromatographic Determination ◽  
Electron Capture Detection ◽  
Gas Liquid Chromatography ◽  
Relative Standard ◽  
Liquid Chromatographic Determination ◽  
Inorganic Iodine ◽  
Liquid Chromatographic

Abstract Total inorganic iodine in milk is determined by conversion to iodobutanone, which is quantitated by gas-liquid chromatography and electron capture detection. As little as 10 μg/L can be determined. The thyroid-active iodine content of milk can be determined rapidly with a relative standard deviation of 1.9%. Average recoveries for added iodide and iodine were 95.5 and 94.6%, respectively.

Surrogate-Assisted Determination of 2,3,7,8-Tetrachlorodibenzo-p-Dioxin in Fish by Electron Capture Capillary Gas Chromatography

1986 ◽  
Vol 69 (6) ◽  
pp. 976-980
Author(s):  
Richard A Niemann
Keyword(s):  
Gas Chromatography ◽  
Electron Capture ◽  
Capillary Gas Chromatography ◽  
Capillary Column ◽  
Electron Capture Detection ◽  
Matrix Interference ◽  
Relative Standard ◽  
Tetrachlorodibenzo P Dioxin ◽  
Liquid Chromatographic

Abstract Surrogate spiking the sample with 1000 parts per trillion (pptr) 1,3,7,8-tetrachlorodibenzo-p-dioxin (1378-TCDD) has doubled analytical throughput in determining toxic 2378-TCDD (analyte) at the low partper- trillion level in fish, using multicolumn high resolution liquid chromatographic cleanup before quantitation by capillary gas chromatography with electron capture detection. The 1378- and 2378-TCDD were recovered equally and were well separated by the capillary column so that the earlier-eluting surrogate did not interfere with the quantitation of levels of analyte many-fold lower. Matrix interference contributed &lt;1 % bias in surrogate quantitation. Using surrogate recovery to correct for analyte losses during analysis, accuracy averaged (n = 7) 105% in determining 18 or 45 pptr 2378-TCDD added to fish without detectable bioincurred analyte. Analyses of selected fish with bioincurred 2378-TCDD gave results comparable to earlier work where recovery correction required a second analysis of sample fortified with analyte. With surrogate fortification, repeatability of determination (n = 3 or 4) improved markedly to &lt;5% relative standard deviation at 37-46 pptr.

METHOD FOR EXPERIMENTAL DETERMINATION OF THE LIQUID DIELECTRIC RESOURCE AND MEASURES FOR ITS RESTORATION

2019 ◽  
pp. 36-41
Author(s):  
S. P. Vysogorets ◽  
A. N. Nazarychev ◽  
A. A. Pugechov
Keyword(s):  
Experimental Determination ◽  
Oil Quality ◽  
Technical Problem ◽  
Transformer Oil ◽  
Quality Stability ◽  
Transformer Oils ◽  
Resource Characteristics ◽  
Theoretical Foundations

The theoretical foundations of changes in the transformer oil quality characteristics, depending on the aging degree, are presented. The introduction of a new indicator of the exploitational transformer oils quality – “stability against oxidation” – is substantiated as a way of solving the scientific and technical problem of assessing the resource characteristics of a transformer insulating system. In order to select the best measures to maintain the quality of power transformers insulating oils, a newly developed “Method for the Experimental Determination of the Luquid Dielectric Resource and Measures for its Restoration” is presented.

scholarly journals Validation of a Stability-Indicating RP-HPLC Method for Determination of L-Carnitine in Tablets

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Roghaieh Khoshkam ◽  
Minoo Afshar
Keyword(s):  
Hplc Method ◽  
Stability Factor ◽  
Forced Degradation ◽  
Validation Data ◽  
Column Temperature ◽  
Stability Indicating ◽  
Rp Hplc ◽  
Relative Standard ◽  
Forced Degradation Studies

A rapid and stability-indicating RP-HPLC method was developed for determination of l-carnitine in tablets. The separation was based on a C18 analytical column using a mobile phase which consisted of 0.05 M phosphate buffer (pH = 3): ethanol (99 : 1), including 0.56 mg/mL of sodium 1-heptanesulfonate. Column temperature was set at 50°C and quantitation was achieved by UV detection at 225 nm. In forced degradation studies, the drug was subjected to oxidation, hydrolysis, photolysis, and heat. Among the different stress conditions, the exposure to acidic and basic conditions was found to be an important adverse stability factor. The method was validated for specificity, selectivity, linearity, precision, accuracy, and robustness. The applied procedure was found to be linear in l-carnitine concentration range of 84.74–3389.50 µg/mL (r2=0.9997). Precision was evaluated by replicate analysis in which relative standard deviation (RSD) values for areas were found below 2.0%. The recoveries obtained (100.83%–101.54%) ensured the accuracy of the developed method. The expanded uncertainty (3.14%) of the method was also estimated from method validation data. Accordingly, the proposed validated and rapid procedure was proved to be suitable for routine analyzing and stability studies of l-carnitine in tablets.

scholarly journals Validation and Uncertainty Estimation of an Ecofriendly and Stability-Indicating HPLC Method for Determination of Diltiazem in Pharmaceutical Preparations

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Fahimeh Sadeghi ◽  
Latifeh Navidpour ◽  
Sima Bayat ◽  
Minoo Afshar
Keyword(s):  
Degradation Products ◽  
Pharmaceutical Preparations ◽  
Hplc Method ◽  
Forced Degradation ◽  
Solution Ph ◽  
Validation Data ◽  
Column Temperature ◽  
Stability Indicating ◽  
Relative Standard

A green, simple, and stability-indicating RP-HPLC method was developed for the determination of diltiazem in topical preparations. The separation was based on a C18analytical column using a mobile phase consisted of ethanol: phosphoric acid solution (pH = 2.5) (35 : 65, v/v). Column temperature was set at 50°C and quantitation was achieved with UV detection at 240 nm. In forced degradation studies, the drug was subjected to oxidation, hydrolysis, photolysis, and heat. The method was validated for specificity, selectivity, linearity, precision, accuracy, and robustness. The applied procedure was found to be linear in diltiazem concentration range of 0.5–50 μg/mL (r2=0.9996). Precision was evaluated by replicate analysis in which % relative standard deviation (RSD) values for areas were found below 2.0. The recoveries obtained (99.25%–101.66%) ensured the accuracy of the developed method. The degradation products as well as the pharmaceutical excipients were well resolved from the pure drug. The expanded uncertainty (5.63%) of the method was also estimated from method validation data. Accordingly, the proposed validated and sustainable procedure was proved to be suitable for routine analyzing and stability studies of diltiazem in pharmaceutical preparations.

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