Static Headspace GC/MS Method for Determination of Methanol and Ethanol Contents, as the Degradation Markers of Solid Insulation Systems of Power Transformers

Molavi, Hoda; Yousefpour, Abbas; Mirmostafa, Akbar; Sabzi, Ali; Hamedi, Sepideh; Narimani, Milad; Abdi, Nazanin

doi:10.1007/s10337-017-3315-1

Cited by 11 publications

(18 citation statements)

References 17 publications

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“…A prepared ethanol-d6 solution is added in a constant amount to all samples, blanks and calibration standards for quantitative analysis. Another internal standard, 2-propanol, has been proposed in the literature [20]. Nevertheless, the proposed method was not validated to ageing experiments or field samples to confirm that 2-propanol is not generated during mineral oil ageing.…”

Section: Methanol Determinationmentioning

confidence: 96%

“…Since the first method for the analysis of methanol in transformer oil became available in 2007 [1], a handful of publications have presented analytical methods for its determination [4,9,[18][19][20][21]. The characteristics of these methods are presented in Table 1.…”

Section: Methanol Determinationmentioning

confidence: 99%

“…Then, the vapor is transferred by the carrier gas into the gas chromatography (GC) column for separation. Molavi et al [20] present an HS method where gas samples are manually injected into the GC. A fused silica capillary column of mid-polarity phase (6% cyanopropylphenyl and 94% dimethylpolysiloxane) for separation of volatile compounds has frequently been used for this application [18,19,21].…”

Section: Methanol Determinationmentioning

confidence: 99%

“…For component identification, two types of detectors have been coupled with gas chromatography: flame ionization detection (FID) [18] and mass spectrometry (MS) [4,8,[18][19][20][21]. While FID is the most widely used detector for GC, MS is considered the most powerful [22].…”

Section: Methanol Determinationmentioning

confidence: 99%

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Methanol Marker for the Detection of Insulating Paper Degradation in Transformer Insulating Oil

et al. 2019

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This manuscript presents a comprehensive literature review with the aim to provide readers a reference document with up-to-date information on the field of methanol use as a chemical marker. It has been a little more than a decade since methanol was first introduced as a marker for assessing solid insulation condition in power transformers. It all started when methanol was identified in the laboratory during thermal ageing tests carried out with oil-immersed insulating papers and was subsequently also identified in transformer field samples. The first publication on the subject was released in 2007 by our research group. This review covers the methanol fundamentals such as the analytical methods for its determination in transformer oil, which is generally performed by headspace gas chromatography with mass spectrometry or flame ionization as a detector. Current standardization efforts for its determination include ASTM working group 30948 and IEC TC10. Kinetic studies have confirmed the relationship between methanol generation, the number of broken 1,4-β-glycosidic bonds of cellulose and changes in mechanical properties. Laboratory tests have confirmed its stability at different accelerated ageing temperatures. Several utilities have identified methanol during field measurements, case studies on power and some distribution transformers are presented, as well as transformer postmortem investigations. These field-testing results demonstrate its utility in monitoring cellulosic insulation degradation. Recently, a model of methanol interpretation has become available that allows for evaluation of the average degree of polymerization of core type transformer cellulose winding. Methanol has a role as an indicator of cellulosic solid insulation ageing in transformer mineral oil, and it is expected that in the future it will be in routine use by utilities.

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Section: Methanol Determinationmentioning

confidence: 96%

Section: Methanol Determinationmentioning

confidence: 99%

Section: Methanol Determinationmentioning

confidence: 99%

Section: Methanol Determinationmentioning

confidence: 99%

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Methanol Marker for the Detection of Insulating Paper Degradation in Transformer Insulating Oil

et al. 2019

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“…The key parameters of GC-MS that affect chromatographic separation include injection volume, split ratio, carrier gas flow rate, and column temperature [16]. In the actual detection process, abnormal phenomena such as the overlapping, trailing, and disappearing of chromatographic peaks may sometimes be encountered.…”

Section: Selection Of Gc-ms Parametersmentioning

confidence: 99%

Optimization of Ethanol Detection by Automatic Headspace Method for Cellulose Insulation Aging of Oil-immersed Transformers

Zheng

Zhang

et al. 2020

Polymers

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The method using ethanol to evaluate the cellulose insulation aging condition of oil-immersed transformers has been proposed. At present, the dominating method for detecting ethanol in insulating oil is to use headspace–gas-chromatography–mass-spectrometry (HS-GC-MS). However, the problem of quantitative inaccuracy will be sometimes encountered in the actual detection process due to improper instrument parameter setting and improper manual operation. In this study, as an aging marker, ethanol in transformer insulating oil was separated by using VF-624 ms capillary column. The effects of gas-chromatography–mass-spectrometry (GC-MS) optimization conditions, headspace equilibrium temperature, headspace equilibrium time and standard solution preparation method on the determination of ethanol content in oil were discussed, and optimized measures were proposed. The experimental results showed that the measurement can be more accurate under the headspace temperature of 80 °C and the headspace time of 40 min, and relative standard deviation percentage (RSD%) could reach to 4.62% under this condition. It was also pointed out that, for the preparation of standard solution, the method which controlled the sampling volume of anhydrous ethanol by microliter syringe could make the peak area of ethanol chromatogram have a better linear relationship with the standard curve. Under the similar linear range, the goodness of fitting curve without diluting process could be as high as 0.9993, while the method of preparing the stock solution and diluting stepwise to obtain the fitting curve only had a goodness of 0.9910. The method was validated by standard addition recovery test, and the recovery values obtained were between 90.3% and 95.8%. The optimized method is of great significance for the measurement of ethanol dissolved in insulating oil.

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Simultaneous Analysis of Formaldehyde and Methanol Emissions During Curing Reactions of Polyester-melamine Coatings

Rippatha,

Schwarzinger

2024

Chromatographia

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This paper introduces a new derivatization agent for the simultaneous quantification of formaldehyde and methanol during curing reactions of complex organic coatings. Formaldehyde emitted from a polyester-melamine coating is derivatized in a gas phase reaction with unsymmetrical dimethylhydrazine (UDMH) to form formaldehyde dimethylhydrazone (FDMH). UDMH and FDMH tend to degrade at temperatures above 200 °C rather fast. The applicability of derivatization agent and analyte as well as their degradation products are therefore discussed thoroughly. In this method curing temperatures of 150 °C with incubation times between 0.1 and 60 min are used to trigger crosslinking reactions. The emissions of formaldehyde and methanol are continuously quantified with headspace gas chromatography to obtain an emission trend. While one of the main sources of formaldehyde is the demethylolation during crosslinking, methanol is produced via hexamethoxymethylmelamine (HMMM) deetherification and as a condensation byproduct. The emission monitoring shows a high potential for comparative and mechanistic investigations. Results show good repeatability with low standard deviations (< 7%) with a quantification limit of 2.09 µg for formaldehyde and 2.08 µg for methanol.

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Static Headspace GC/MS Method for Determination of Methanol and Ethanol Contents, as the Degradation Markers of Solid Insulation Systems of Power Transformers

Cited by 11 publications

References 17 publications

Methanol Marker for the Detection of Insulating Paper Degradation in Transformer Insulating Oil

Methanol Marker for the Detection of Insulating Paper Degradation in Transformer Insulating Oil

Optimization of Ethanol Detection by Automatic Headspace Method for Cellulose Insulation Aging of Oil-immersed Transformers

Simultaneous Analysis of Formaldehyde and Methanol Emissions During Curing Reactions of Polyester-melamine Coatings

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