Addition Of Detergent Research Articles

Vitis vinifera Lipoxygenase LoxA is an Allosteric Dimer Activated by Lipidic Surfaces

Lipoxygenases catalyze the peroxidation of poly-unsaturated fatty acid chains either free or esterified in membrane lipids. Vitis vinifera LoxA is transcriptionally induced at ripening onset and localizes at the inner chloroplastic membrane where it is responsible for galactolipid regiospecific mono- and di-peroxidation. Here we present a kinetic and structural characterization of LoxA. Our X-ray structures reveal a constitutive dimer with detergent induced conformational changes affecting substrate binding and catalysis. In a closed conformation, a LID domain prevents substrate access to the catalytic site by steric hindrance. Detergent addition above the CMC destabilizes the LID and opens the dimer with both catalytic sites accessible from the same surface framed by the PLAT domains. As a consequence, detergent molecules occupy allosteric sites in the PLAT/catalytic domain interfaces. These structural changes are mirrored by increased enzymatic activity and positive cooperativity when the substrate is provided in micelles. The ability to interact with micelles is lost upon dimer destabilization by site-directed mutagenesis as assessed by tryptophan fluorescence. Our data allow to propose a model for protein activation at the membrane, classifying LoxA as an interfacial enzyme acting on fatty acid chains directly from the membrane similar to mammalian 15-LOX and 5-LOX.

Stimulation of cytochrome c oxidase activity by detergents

Cytochrome c oxidase (CytcO) is an integral membrane protein, which catalyzes four-electron reduction of oxygen linked to proton uptake and pumping. Amphipathic molecules bind in sites near the so-called K proton pathway of CytcO to reversibly modulate its activity. However, purification of CytcO for mechanistic studies typically involves the use of detergents, which may interfere with binding of these regulatory molecules. Here, we investigated the CytcO enzymatic activity as well as intramolecular electron transfer linked to proton transfer upon addition of different detergents to bovine heart mitoplasts. The CytcO activity increased upon addition of alkyl glucosides (DDM and DM) and the steroid analog GDN. The maximum stimulating effect was observed for DDM and DM, and the half-stimulating effect correlated with their CMC values. With GDN the stimulation effect was smaller and occurred at a concentration higher than CMC. A kinetic analysis suggests that the stimulation of activity is due to removal of a ligand bound near the K proton pathway, which indicates that in the native membrane this site is occupied to yield a lower than maximal possible CytcO activity. Possible functional consequences are discussed.

Binding Mechanism of Nitro Musks to Human Lactoferrin: Multispectral Approach, Docking and Molecular Dynamics Simulation.

Nitro musks are highly bioaccumulative and potentially carcinogenic, commonly used as additives in fabric softeners, detergents, and other household products. Furthermore, these substances have been detected in breast milk and human adipose tissue, posing a risk of direct exposure to pregnant women and infants. Human lactoferrin (HLF) is abundant in colostrum, and plays an important role in the non-specific immune system of the human body. In this study, the mechanisms of action of two nitro musk compounds, typical examples of synthetic musks, with HLF were investigated using molecular docking, dynamics simulation and multispectral methods. The fluorescence findings demonstrated that nitro musks quenched the intrinsic fluorescence of human lactoferrin through static quenching. Thermodynamic analysis of the binding parameters suggested that hydrophobic interactions acted synergistically in the formation of the complex. Moreover, analyses utilizing multispectral techniques, such as Fourier transform infrared (FTIR) spectroscopy, validated that the microenvironment and structure of HLF were altered in the presence of nitro musks. Finally, molecular docking and molecular dynamics simulations were employed to explore the specific binding mode of nitro musks with HLF and to assess the stability of the complex. These findings may provide a reference for assessing health risks to pregnant women and infants.

Optimization and characterization of solvent-tolerant lipases from Geobacillus stearothermophilus CHI1

Lipases are enzymes attractive for their use in enzymatic biotechnology, mainly those produced by extremophiles. Recently, the isolation of thermophilic bacteria Geobacillus spp. from the geothermal waters of the crater lake of the “El Chichón” volcano in Mexico was reported. In this work, the lipolytic activity of the G. stearothermophilus CHI1 strain was characterized and optimized. This strain was able to produce enzymes with maximum lipolytic activity at 60 °C and 80°C, with pH values of 5, 9, and 11; showed tolerance of solvents; was able to perform catalysis independently of metal ions; and showed greater affinity towards medium-chain substrates. Results of biochemical characterization and optimization suggest the presence of more than one type of lipolytic activity in Geobacillus stearothermophilus CHI1. All these characteristics make these enzymes attractive in biotechnological processes at high temperatures and alkaline pH (e.g., detergent additives), as well as in the understanding of their biological utility in Geobacillus.

On fuel and deposits. Part 1

Introduction (problem statement and relevance). Generally, deposits or sediments are an inevitable consequence of processes of mixture formation and combustion in the engine cylinder, complex physical and chemical processes with the hydrocarbon “participants” of this process – fuel and oil. There is no consensus in the scientific community regarding the role of these participants. Some researchers consider the “fuel” factor to be the predominant one, the others have no less reason to think it is the “oil” factor. Meanwhile, understanding the nature of formation of deposits, both the “cold” ones (in the intake path) and the “hot” ones (in the combustion chamber) is the most important condition in order to determine the methods to combat this negative phenomenon, in particular, and due to development of scientifically grounded requirements for qualitative characteristics of both fuels and oils. The relevance of the issue increases due to the fact that the existing methods of fuel testing based on foreign procedures with application of foreign reference engines become almost inaccessible following refusal of a number of the manufacturers of reference engines for standardized testing to provide further technical support caused by phasing-out of models of these engines. Moreover, during the period of common confusion in the European engine-building and uncertainty over prospects of the automotive industry on the whole, no solution was taken either for the procedure or for the new reference engine for the direct fuel injection engines increasingly dominant in the market of gasoline engines. The vacuum created is occupied by unapproved procedures with application of engines having different designs. In such conditions, correct comparison of test results obtained in different laboratories becomes almost impossible, while the results themselves lose their practical value.The purpose of the study and its practical significance consist in study of the mechanism of deposits formation in spark ignition engines and development of methods to test fuels for tendency to form certain types of deposits. Development of domestic scientific research methodological and experimental basis for engine testing of fuels and oils for deposits formation tendencies.Scientific novelty and results. The experimental studies, and the thermal gravimetric ones in particular, convincingly prove the hypothesis of domination of the fuel factor in formation of “cold” deposits on the intake valves. It has been experimentally shown that the results of testing following the new procedures adequately reflect the efficiency of using detergent additives.

Enhancing Alkaline Protease Stability through Enzyme-Catalyzed Crosslinking and Its Application in Detergents

Enzymatic additives, particularly alkaline proteases, play a crucial role in enhancing detergent effectiveness against protein-based stains. Despite advancements in enzyme stabilization techniques, there is a need for innovative strategies to further improve protease stability in laundry detergents. However, research exploring the utilization of substrate imprinting technology to achieve this objective remains limited. Therefore, this study aims to enhance the stability of alkaline proteases in laundry detergents by employing casein as an imprinting substrate and utilizing transglutaminase-mediated (TGase) crosslinking to modify proteases 102 and 306. The optimal temperature, pH, and thermal stability of the modified alkaline proteases 102 and 306 showed no significant changes. However, these two modified alkaline proteases exhibited varying degrees of improvement in stability among the 14 detergent additives tested. Under 40 °C incubation for 24 h, the relative enzyme activity of modified alkaline protease 102 increased approximately 1.4–15-fold in AEO-9, BS-12, CMI, APG, FMEE, and SOE, while the relative enzyme activity of modified alkaline protease 306 increased approximately 1.2–3.7-fold across different additives (FMEE, AEO-9, BS-12, SOE, FAA, and AEC-9Na). These modified proteases demonstrated improved stability and wider applicability across commercial detergent formulations available. Integrated into standard laundry detergent at a 1:7 ratio before and after modification, they effectively removed protein stains from the cotton fabric after 24 h of 40 °C incubation. These findings provide insights into more effective stain-removal techniques.

Improving protocols for α-synuclein seed amplification assays: analysis of preanalytical and analytical variables and identification of candidate parameters for seed quantification.

The effect of preanalytical and analytical factors on the α-synuclein (α-syn) seed amplification assay's (SAA) performance has not been fully explored. Similarly, there is limited knowledge about the most suitable assay protocol and kinetic parameters for misfolded α-syn seed quantification. We studied the effect of centrifugation, repeated freeze-thaw cycles (up to seven), delayed freezing, detergent addition, and blood contamination on the performance of the cerebrospinal fluid (CSF) α-syn SAA real-time quaking-induced conversion (RT-QuIC). Moreover, we analysed the inter- and intra-plate variability, the recombinant protein batch effect, and the RT-QuIC parameters' variability when multiple samples were run in controlled conditions. Finally, we evaluated the assay potential of quantifying α-syn seed by assessing kinetic curves in serial CSF dilutions. Among tested preanalytical variables, a≥0.01 % blood contamination and adding detergents significantly affected the RT-QuIC kinetic parameters and the number of positive replicates. Increasing the number of replicates improved result reproducibility. The number of positive replicates in serially diluted CSF samples improved discrimination between samples with high and low seeding activity, and the time to threshold (LAG) was the most reliable kinetic parameter in multiple experiment settings. Preanalytical variables affecting α-syn RT-QuIC performance are limited to blood contamination and detergent addition. The number of positive replicates and the LAG are the most reliable variables for quantifying α-syn seeding activity. Their consistent measurement in serial dilution experiments, especially when associated with an increased number of sample replicates, will help to develop the α-syn RT-QuIC assay further into a quantitative test.

Stable and effective eco-enzyme cocktails in powder and liquid form of Stachybotrys microspora used as detergent additives

ObjectiveThe present work aims to optimize fermentation parameters for the simultaneous production of eco-enzymes: proteases, amylases, and endoglucanases from the same fungus Stachybotrys microspora, and to evaluate their stability in free form and formulated in lye as detergent additives. MethodsInitially, enzyme cocktail production was assayed in a medium comprising inexpensive waste biomass. Using the best substrate, we investigated the effect of its different concentrations and the NaCl concentration on the three enzymes co-production. Next, we studied the effect of several additives on the storage stability of the lyophilized enzyme cocktail (powder in liquid forms) free and incorporated in commercial laundry detergent. Finally, the washing efficiency analysis of the newly formulated enzyme cocktail was evaluated on dirty tissue pieces with different stains. ResultsThe highest enzymatic cocktail production was achieved at 30 °C for 96 h after adding 0.1% NaCl and 1.5% wheat bran as waste biomass in the basal culture medium. The effect of adding maltodextrin, sucrose, or polyethylene glycol 4000 during freeze-drying showed that maltodextrin is the best additive to protect the activities of proteases, amylases, and cellulases of liquid and powder enzyme form. Additionally, the liquid formulation of these enzymes showed excellent stability and compatibility with 1% maltodextrin and 10% glycerol. Interestingly, we have developed a new formulation of an enzyme cocktail (liquid and powder) stable and highly compatible with detergents. Comparing the washing performance of different formulations containing our enzyme cocktail to commercial ones showed significantly better removal of different types of stains. ConclusionsThis research shows a cost-effective approach to simultaneously produce proteases, amylases, and endoglucanases from Stachybotrys microspora that could be considered a compatible detergent additive in the green detergent industry.

Improved production of alkaline and solvent-stable proteases from a halotolerant Exiguobacterium isolate through heterologous expression

Halophiles are excellent sources of detergent proteases that are attributed to stability in alkaline pH, salts, surfactants, and hydrophobic solvents. The lower enzymatic yields and tedious downstream processes necessitate the search for newer halophilic sources. We have previously reported a halotolerant Exiguobacterium sp. TBG-PICH-001, which secretes solvent-tolerant alkaline protease/s. The present study describes the heterologous expression of two protease genes, namely, rsep metalloprotease (WP_195864791, 1.23 Kb) and tpa serine protease (WP_195864453, 0.879 Kb) genes. These were cloned into the pET 22b + plasmid vector and expressed in Escherichia coli BL21(DE3). The recombinant proteases rsep and tpa showed respective yields of 6.3 and 6.7 IU/mg, 11 and 12-fold higher than the crude native protease/s from TBG-PICH-001. These showed soluble expression at 46 and 32 KDa, respectively. These were purified to homogeneity through Ni-NTA-affinity chromatography. The purified proteases were characterized for properties like pH & temperature optima and stability, substrate specificity, kinetic parameters, and detergent attributes. They showed affinity towards various substrates with a respective Km of 392 and 301 μM towards casein. The recombinant proteases exhibited stability in the alkaline pH (7–10), surfactants, metal ions, detergents, and hydrophobic solvents, rendering their suitability as detergent additives.

Molecular Biology Applications of Psychrophilic Enzymes: Adaptations, Advantages, Expression, and Prospective.

Psychrophilic enzymes are primarily produced by microorganisms from extremely low-temperature environments which are known as psychrophiles. Their high efficiency at low temperatures and easy heat inactivation property have attracted extensive attention from various food and industrial bioprocesses. However, the application of these enzymes in molecular biology is still limited. In a previous review, the applications of psychrophilic enzymes in industries such as the detergent additives, the food additives, the bioremediation, and the pharmaceutical medicine, and cosmetics have been discussed. In this review, we discuss the main cold adaptation characteristics of psychrophiles and psychrophilic enzymes, as well as the relevant information on different psychrophilic enzymes in molecular biology. We summarize the mining and screening methods of psychrophilic enzymes. We finally recap the expression of psychrophilic enzymes. We aim to provide a reference process for the exploration and expression of new generation of psychrophilic enzymes.

Evaluation of extracellular alkaline proteases from Bacillus for environmentally friendly detergent additives

Growing demand for environmentally friendly and sustainable enzyme solutions drives markets for alkaline proteases across various industries. Alkaline proteases produced by different Bacillus strains exhibit unique properties and versatility. Production of alkaline proteases from Bacillus amyloliquefaciens TBRC 2902, B. siamensis TBRC 1180, B. subtilis TBRC 6663, and B. velezensis TBRC 7773 was optimized by adjusting production media, considering carbon and nitrogen sources to enhance extracellular enzyme activities. Optimized extracellular protease activity was achieved using tapioca starch for TBRC 2902 and TBRC 1180, and soluble starch for TBRC 7773, while both carbon sources were optimal for TBRC 6663. Skim milk was an equally effective nitrogen source for TBRC 2902, TBRC 1180, and TBRC 7773, whereas soytone was as effective as yeast extract for TBRC 6663. Inorganic nitrogen sources, such as diammonium hydrogen phosphate for TBRC 2902 and potassium nitrate for TBRC 1180, enhanced alkaline protease activity by 10-20%. The protease from B. siamensis TBRC 1180 exhibited optimal pH and temperature values of 9.0 and 60°C, respectively, while the others had optimal values of 8.0 and 50°C. All enzymes tolerated non-ionic surfactants, retaining over 40% activity after 24 hours exposure to Triton X-100, Tween-20, and Tween-80, indicating their potential as detergent additives.

UV mutagenesis for lipase overproduction from Bacillus cereus ATA179, nutritional optimization, characterization and its usability in the detergent industry

In this study, the wild-type Bacillus cereus ATA179 was mutagenized by random UV mutagenesis to increase lipase production. The mutant with maximum lipolytic activity was named Bacillus cereus EV4. The mutant strain (10.6 U/mL at 24 h) produced 60% more enzyme than the wild strain (6.6 U/mL at 48 h). Nutritional factors on lipase production were investigated. Sucrose was the best carbon source, (NH4)2HPO4 was the best nitrogen source and CuSO4 was the best metal ion source. Mutant EV4 showed a 32% increase in lipase production in the modified medium. The optimum temperature and pH were found to be 60 °C and 7.0, respectively. CuSO4, CaCl2, LiSO4, KCl, BaCl2, and Tween 20 had an activating effect on the enzyme. V max and K m values were found to be 17.36 U/mL and 0.036 mM, respectively. The molecular weight was determined as 28.2 kDa. The activity of lipase was found to be stable up to 60 days at 20 °C, 75 days at 4 °C, and 90 days at −20 °C. The potential of lipase in the detergent industry was investigated. The enzyme was not affected by detergent additives but was effective in removing stains in fabrics contaminated with oily substances.

STUDY OF THE EXPLOITATIVE PROPERTIES OF THE DEVELOPED ADDITIVES AND THEIR APPLICATION

Naphthalene additives, as indicated in the literature review, are classified as detergent additives. Additives of this type are primarily used in engine oils. It is known that the composition of the “D” group oil should include an effective package of additives to achieve the level of performance properties, which ensures long-term performance of the most forced engines especially in severe operating conditions. To date, there is no universal method for assessing the behavior of oil at high temperatures, therefore oil is usually tested via several (laboratory and stand) methods. For example, in domestic practice, a four-stage system for determining the quality of newly created (experimental) oil products is provided.

Elimination of a Mixture of Microplastics Using Conventional and Detergent-Assisted Coagulation.

The research described here investigated the suitability of coagulation process in the elimination of microplastics from tap water. The purpose of the study was to assess the effects of microplastic type (PE1, PE2, PE3, PVC1, PVC2, and PVC3), tap water pH (3, 5, 7, and 9), coagulant doses (0, 0.025, 0.05, 0.1 and 0.2 g/L), and microplastic concentration (0.05, 0.1, 0.15, and 0.2 g/L) on elimination efficiency with coagulation utilizing Al and Fe coagulants as well coagulation combined with a detergent (SDBS) addition. This work also explores the elimination of a mixture of two microplastics (PE and PVC) that are significant in terms of the environment. The effectiveness of conventional and detergent-assisted coagulation was calculated as a percentage. The fundamental characteristics of microplastics were also determined via LDIR analysis, and on the basis of these findings, particles that were more coagulation-prone were identified. The maximum reduction in MPs was achieved with tap water's neutral pH and a coagulant dosage of 0.05 g/L. The addition of SDBS increased the loss of the plastic microparticles' efficacy. A removal efficiency of greater than 95% (Al-coagulant) and 80% (Fe-coagulant) was achieved for each of the microplastics tested. The removal efficiency of the microplastic mixture with SDBS-assisted coagulation was obtained at a level of 95.92% (AlCl3·6H2O) and 98.9% (FeCl3·6H2O). After each coagulation procedure, the mean circularity and solidity of the unremoved particles increased. This confirmed that particles with irregular shapes are easier to completely remove.

Anomalous Oligomerization Behavior of E. coli Aquaporin Z in Detergent and in Nanodiscs.

Aquaporins are tetrameric integral membrane proteins that act as water channels, and can also permeabilize membranes to other solutes. The monomer appears to be the functional form despite all aquaporins being organized as tetramers, which therefore must provide a clear functional advantage. In addition to this quaternary organization, some aquaporins can act as adhesion molecules in membrane junctions, when tetramers located in opposing membranes interact via their extracellular domains. These stacked forms have been observed in a range of aquaporins, whether using lipidic membrane environments, in electron crystallography, or using detergent micelles, in single-particle cryo-electron microscopy (cryo-EM). In the latter technique, structural studies can be performed when the aquaporin is reconstituted into nanodiscs of lipids that are surrounded by a protein scaffold. During attempts to study E. coli Aquaporin Z (AqpZ), we have found that in some conditions these nanodiscs tend to form filaments that appear to be either thicker head-to-tail or thinner side-to-side stacks of nanodiscs. Nanodisc oligomerization was observed using orthogonal analytical techniques analytical ultra-centrifugation and mass photometry, although the nature of the oligomers (head-to-tail or side-to-side) could not be determined. Using the latter technique, the AqpZ tetramer itself formed oligomers of increasing size when solubilized only in detergent, which is consistent with multiple stacking of AqpZ tetramers. We observed images consistent with both of these filaments in negative staining EM conditions, but only thicker filaments in cryo-EM conditions. We hypothesize that the apparent nanodisc side-to-side arrangement that can only be visualized in negative staining conditions is related to artifacts due to the sample preparation. Filaments of any kind were not observed in EM when nanodiscs did not contain AqpZ, or after addition of detergent into the nanodisc cryo-EM preparation, at concentrations that did not disrupt nanodisc formation. To our knowledge, these filaments have not been observed in nanodiscs preparations of other membrane proteins. AqpZ, like other aquaporins has a charge asymmetry between the cytoplasmic (more positive) and the extracellular sides, which may explain the likely head-to-tail stacking observed, both in nanodisc preparations and also in detergent micelles.

Chalcogen Bonding (ChB) as a Robust Supramolecular Recognition Motif of Benzisothiazolinone Antibacterials.

1,2-benzisothiazol-3(2H)-one derivatives are highly active against a broad spectrum of fungi as well as Gram positive and Gram negative bacteria. For this reason they are extensively used, e.g., as additives in detergents, leather products, paper coatings, and antifouling paintings. In this paper experimental findings are reported proving that the sulfur atom of benzisothiazolinones have a remarkable tendency to form short and directional chalcogen bonds on the extension of the covalent N-S bond and, to a lesser extent, of the C-S bond. Analyses of the Cambridge Structural Database confirm the interaction as a primary recognition motif of these systems. The electrophilicity of sulfur is crucial in the chemical reactions initiating the cascade of events resulting in the biopharmacological activities of benzisothiazolinones. The reported results suggest that the electrophility of sulfur may play a role also at earlier stages than the reactive ones, namely it may pin the compounds at the active site of target enzymes via chalcogen bonds that preorganize the system in the conformation required for the bonds formation/cleavage determining the biopharmacological activity.

Plant dehydroascorbate reductase moonlights as membrane integrated ion channel

Plant dehydroascorbate reductases (DHARs) are only known as soluble antioxidant enzymes of the ascorbate-glutathione pathway. They recycle ascorbate from dehydroascorbate, thereby protecting plants from oxidative stress and the resulting cellular damage. DHARs share structural GST fold with human chloride intracellular channels (HsCLICs) which are dimorphic proteins that exists in soluble enzymatic and membrane integrated ion channel forms. While the soluble form of DHAR has been extensively studied, the existence of a membrane integrated form remains unknown. We demonstrate for the first time using biochemistry, immunofluorescence confocal microscopy, and bilayer electrophysiology that Pennisetum glaucum DHAR (PgDHAR) is dimorphic and is localized to the plant plasma membrane. In addition, membrane translocation increases under induced oxidative stress. Similarly, HsCLIC1 translocates more into peripheral blood mononuclear cells (PBMCs) plasma membrane under induced oxidative stress conditions. Moreover, purified soluble PgDHAR spontaneously inserts and conducts ions in reconstituted lipid bilayers, and the addition of detergent facilitates insertion. In addition to the well-known soluble enzymatic form, our data provides conclusive evidence that plant DHAR also exists in a novel membrane-integrated form. Thus, the structure of DHAR ion channel form will help gain deeper insights into its function across various life forms.

Fully integrated downstream process to enable next-generation manufacturing.

Next-generation manufacturing (NGM) has evolved over the past decade to a point where large biopharmaceutical organizations are making large investments in the technology and considering implementation in clinical and commercial processes. There are many well-considered reasons to implement NGM. For the most part, organizations will not fund NGM unless the implementation benefits the funding organization by providing reduced costs, reduced time, or additional needed capabilities. Productivity improvements gained from continuous purification are shown in this work, which used a new system that fully integrates and automates several downstream unit operations of a biopharmaceutical process to provide flexibility and easy implementation of NGM. The equipment and automation needed to support NGM can be complicated and expensive. Biopharmaceutical Process Development considered two options as follows: (1) design its own NGM system or (2) buy a prebuilt system. PAK BioSolutions offers a turn-key automated and integrated system that can operate up to four continuous purification stages simultaneously, while maintaining a small footprint in the manufacturing plant. The system provides significant cost benefits (~10× lower) compared with the alternative-integration of many different pieces of equipment through a Distributed Control System that would require significant engineering time for design, automation, and integration. Integrated and Continuous Biomanufacturing can lead to significant reductions in facility size, reduced manufacturing costs, and enhanced product quality when compared with the traditional batch mode of operation. The system uses new automation strategies that robustly link unit operations. We present the optimized process fit, sterility and bioburden control strategy, and automation features (such as pH feedback control and in-line detergent addition), which enabled continuous operation of a 14-day end-to-end monoclonal antibody purification process at the clinical manufacturing scale.

Determination of Viscosity Improvers and Detergent Additives in Synthetic Motor Oils by Gel Permeation Chromatography

We proposed a procedure for the simultaneous determination of viscosity improvers and detergent additives in synthetic oils by gel permeation chromatography, including the preliminary liquid extraction of polar additives, solid-phase extraction of polymer additives on silica modified with magnesium oxide from oil raffinate, and the subsequent determination of analytes. The procedure was used to determine viscosity improvers and detergent additives in fresh and used synthetic motor oils, to control the quality of oils at different stages of operation, and to monitor the degree of purification of oils during their regeneration. In-process monitoring of additive concentrations during the operation of automotive equipment enables the timely control of the dynamics of engine oil degradation throughout its use and proper recommendations for its replacement in the system. The procedure was tested in the analysis of fresh and used multigrade synthetic motor oils Shell Helix Ultra 5W-30 and TP MAX Total 10W-40 and fresh multigrade synthetic motor oil Shell Rimula R5M 10W-40.

Determination of Viscosity Improvers and Detergent Additives in Synthetic Motor Oils by Gel Permeation Chromatography

Determination of Viscosity Improvers and Detergent Additives in Synthetic Motor Oils by Gel Permeation Chromatography