Separation & Identification of Organic Compounds in Lubricating Oil Additives Using TLC & GC-MS

Abstract

Thin layer chromatography (TLC) and Gas Chromatography-Mass Spectrometry (GC-MS) techniques are proposed for qualitative analysis of lubricating oil additives (Hitec 2915). The additives were dissolved in heptanes, extracted with mixed solvents heptane: acetonitrile (3:2) and spotted on TLC paper. The best combination solvents as developer for TLC analysis were carbon tetrachloride: heptanes (9:1) mixture. Each separated streak was scraped, redissolved in acetonitrile and evaporated to 0.5 ml volume then analyzed by GC-MS for identification. Fourteen compounds[2-Ethyl-1-hexanol; 2-(t-butyl)-phenol; 2,4-bis-(t-butyl)-1-methoxy benzene; 2,6-bis-(t-Butyl)-2,5-cyclohexadiene-1,4-dione; 2,4-bis-(t-Butyl)-phenol; 3,5-bis-(t-Butyl)-phenol; Decanoic acid methyl ester; Tridecanol; 1,1-Diphenyl hydrazine; 1,2-Benzene dicarboxylic acid dibutyle ester; S-Triazol 1, 5-A-pyridine 8-amino 2-phenyl; Phenol-2, 6-bis-(t-butyl); Phenol-2,5-bis-(tbutyl); Phenol-2,4,6-Tris-(t-butyl)]were identified in this study. The mass spectral data obtained for each separated compound were compared with the standard spectral data (library search similarity) of each compound.

Mass spectrometry molecular fingerprinting of mineral and synthetic lubricant oils

“…Although we have not performed a detailed structural analysis of these marker ions, as our goal was to achieve mainly quality control and adulteration/counterfeiting screening, it is likely that these ions are from impurities or the additives added to improve performance. 4,5,19 Figure 3 shows the superimposed FTIR-ATR spectra for the same representative samples of mineral and synthetic oil used before (Figure 1). Previous studies have applied IR spectroscopy mainly to investigate the degrees of oxidation of lubricating oils, 9 although reports from the control agency in Brazil (ANP) usually claim to have detected non-conformities in synthetic oils via IR spectroscopy.…”

“…The ESI(+)‐MS for the representative synthetic oil (Figure 1B) is highly distinct from that of the mineral oil, displaying a much reduced number of ions and being nearly free from the “ion grass” that is characteristic of crude oil products. Although we have not performed a detailed structural analysis of these marker ions, as our goal was to achieve mainly quality control and adulteration/counterfeiting screening, it is likely that these ions are from impurities or the additives added to improve performance 4,5,19 . Some of them are known, such as those of m / z 173 and m / z 129 from polyalkylmethacrylates, m / z 279 from 1,2‐benzene dicarboxylic acid dibutyl ester and m /z 281 from alkyl diphenyl amine 4,5,20 …”

“…Although we have not performed a detailed structural analysis of these marker ions, as our goal was to achieve mainly quality control and adulteration/counterfeiting screening, it is likely that these ions are from impurities or the additives added to improve performance 4,5,19 . Some of them are known, such as those of m / z 173 and m / z 129 from polyalkylmethacrylates, m / z 279 from 1,2‐benzene dicarboxylic acid dibutyl ester and m /z 281 from alkyl diphenyl amine 4,5,20 …”

“…To improve performance, additives are also added to lubricant oils, particularly to the more valuable and higher performance synthetic oils, and may represent 5-25% of their molecular composition. 4,5 Viscosity analysis is one of the parameters most used for quality control in automotive lubricating oils, 6 but techniques focused on the measurement of gross physicochemical properties are expected to display poor performance when the task is to identify adulterations of lubricating oils. The most common adulteration involves mixing less valuable mineral oils with synthetic oils to increase profit in selling.…”

“…Synthetic oils come from laboratory synthesis, which, due to much more controlled conditions and fewer “building blocks,” normally display a lower number of trace components, therefore offering greater performance. To improve performance, additives are also added to lubricant oils, particularly to the more valuable and higher performance synthetic oils, and may represent 5–25% of their molecular composition 4,5 …”

Mass spectrometry molecular fingerprinting of mineral and synthetic lubricant oils

“…Although we have not performed a detailed structural analysis of these marker ions, as our goal was to achieve mainly quality control and adulteration/counterfeiting screening, it is likely that these ions are from impurities or the additives added to improve performance. 4,5,19 Figure 3 shows the superimposed FTIR-ATR spectra for the same representative samples of mineral and synthetic oil used before (Figure 1). Previous studies have applied IR spectroscopy mainly to investigate the degrees of oxidation of lubricating oils, 9 although reports from the control agency in Brazil (ANP) usually claim to have detected non-conformities in synthetic oils via IR spectroscopy.…”

“…The ESI(+)‐MS for the representative synthetic oil (Figure 1B) is highly distinct from that of the mineral oil, displaying a much reduced number of ions and being nearly free from the “ion grass” that is characteristic of crude oil products. Although we have not performed a detailed structural analysis of these marker ions, as our goal was to achieve mainly quality control and adulteration/counterfeiting screening, it is likely that these ions are from impurities or the additives added to improve performance 4,5,19 . Some of them are known, such as those of m / z 173 and m / z 129 from polyalkylmethacrylates, m / z 279 from 1,2‐benzene dicarboxylic acid dibutyl ester and m /z 281 from alkyl diphenyl amine 4,5,20 …”

“…Although we have not performed a detailed structural analysis of these marker ions, as our goal was to achieve mainly quality control and adulteration/counterfeiting screening, it is likely that these ions are from impurities or the additives added to improve performance 4,5,19 . Some of them are known, such as those of m / z 173 and m / z 129 from polyalkylmethacrylates, m / z 279 from 1,2‐benzene dicarboxylic acid dibutyl ester and m /z 281 from alkyl diphenyl amine 4,5,20 …”

“…To improve performance, additives are also added to lubricant oils, particularly to the more valuable and higher performance synthetic oils, and may represent 5-25% of their molecular composition. 4,5 Viscosity analysis is one of the parameters most used for quality control in automotive lubricating oils, 6 but techniques focused on the measurement of gross physicochemical properties are expected to display poor performance when the task is to identify adulterations of lubricating oils. The most common adulteration involves mixing less valuable mineral oils with synthetic oils to increase profit in selling.…”

“…Synthetic oils come from laboratory synthesis, which, due to much more controlled conditions and fewer “building blocks,” normally display a lower number of trace components, therefore offering greater performance. To improve performance, additives are also added to lubricant oils, particularly to the more valuable and higher performance synthetic oils, and may represent 5–25% of their molecular composition 4,5 …”

Mass spectrometry molecular fingerprinting of mineral and synthetic lubricant oils

“…Although we have not performed a detailed structural analysis of these marker ions, as our goal was to achieve mainly quality control and adulteration/counterfeiting screening, it is likely that these ions are from impurities or the additives added to improve performance. 4,5,19 Figure 3 shows the superimposed FTIR-ATR spectra for the same representative samples of mineral and synthetic oil used before (Figure 1). Previous studies have applied IR spectroscopy mainly to investigate the degrees of oxidation of lubricating oils, 9 although reports from the control agency in Brazil (ANP) usually claim to have detected non-conformities in synthetic oils via IR spectroscopy.…”

“…The ESI(+)‐MS for the representative synthetic oil (Figure 1B) is highly distinct from that of the mineral oil, displaying a much reduced number of ions and being nearly free from the “ion grass” that is characteristic of crude oil products. Although we have not performed a detailed structural analysis of these marker ions, as our goal was to achieve mainly quality control and adulteration/counterfeiting screening, it is likely that these ions are from impurities or the additives added to improve performance 4,5,19 . Some of them are known, such as those of m / z 173 and m / z 129 from polyalkylmethacrylates, m / z 279 from 1,2‐benzene dicarboxylic acid dibutyl ester and m /z 281 from alkyl diphenyl amine 4,5,20 …”

“…Although we have not performed a detailed structural analysis of these marker ions, as our goal was to achieve mainly quality control and adulteration/counterfeiting screening, it is likely that these ions are from impurities or the additives added to improve performance 4,5,19 . Some of them are known, such as those of m / z 173 and m / z 129 from polyalkylmethacrylates, m / z 279 from 1,2‐benzene dicarboxylic acid dibutyl ester and m /z 281 from alkyl diphenyl amine 4,5,20 …”

“…To improve performance, additives are also added to lubricant oils, particularly to the more valuable and higher performance synthetic oils, and may represent 5-25% of their molecular composition. 4,5 Viscosity analysis is one of the parameters most used for quality control in automotive lubricating oils, 6 but techniques focused on the measurement of gross physicochemical properties are expected to display poor performance when the task is to identify adulterations of lubricating oils. The most common adulteration involves mixing less valuable mineral oils with synthetic oils to increase profit in selling.…”

“…Synthetic oils come from laboratory synthesis, which, due to much more controlled conditions and fewer “building blocks,” normally display a lower number of trace components, therefore offering greater performance. To improve performance, additives are also added to lubricant oils, particularly to the more valuable and higher performance synthetic oils, and may represent 5–25% of their molecular composition 4,5 …”

Mass spectrometry molecular fingerprinting of mineral and synthetic lubricant oils

“…Although we have not performed a detailed structural analysis of these marker ions, as our goal was to achieve mainly quality control and adulteration/counterfeiting screening, it is likely that these ions are from impurities or the additives added to improve performance. 4,5,19 Figure 3 shows the superimposed FTIR-ATR spectra for the same representative samples of mineral and synthetic oil used before (Figure 1). Previous studies have applied IR spectroscopy mainly to investigate the degrees of oxidation of lubricating oils, 9 although reports from the control agency in Brazil (ANP) usually claim to have detected non-conformities in synthetic oils via IR spectroscopy.…”

“…The ESI(+)‐MS for the representative synthetic oil (Figure 1B) is highly distinct from that of the mineral oil, displaying a much reduced number of ions and being nearly free from the “ion grass” that is characteristic of crude oil products. Although we have not performed a detailed structural analysis of these marker ions, as our goal was to achieve mainly quality control and adulteration/counterfeiting screening, it is likely that these ions are from impurities or the additives added to improve performance 4,5,19 . Some of them are known, such as those of m / z 173 and m / z 129 from polyalkylmethacrylates, m / z 279 from 1,2‐benzene dicarboxylic acid dibutyl ester and m /z 281 from alkyl diphenyl amine 4,5,20 …”

“…Although we have not performed a detailed structural analysis of these marker ions, as our goal was to achieve mainly quality control and adulteration/counterfeiting screening, it is likely that these ions are from impurities or the additives added to improve performance 4,5,19 . Some of them are known, such as those of m / z 173 and m / z 129 from polyalkylmethacrylates, m / z 279 from 1,2‐benzene dicarboxylic acid dibutyl ester and m /z 281 from alkyl diphenyl amine 4,5,20 …”

“…To improve performance, additives are also added to lubricant oils, particularly to the more valuable and higher performance synthetic oils, and may represent 5-25% of their molecular composition. 4,5 Viscosity analysis is one of the parameters most used for quality control in automotive lubricating oils, 6 but techniques focused on the measurement of gross physicochemical properties are expected to display poor performance when the task is to identify adulterations of lubricating oils. The most common adulteration involves mixing less valuable mineral oils with synthetic oils to increase profit in selling.…”

“…Synthetic oils come from laboratory synthesis, which, due to much more controlled conditions and fewer “building blocks,” normally display a lower number of trace components, therefore offering greater performance. To improve performance, additives are also added to lubricant oils, particularly to the more valuable and higher performance synthetic oils, and may represent 5–25% of their molecular composition 4,5 …”