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In this poster a convenient direct injection suppressed ion chromatographic method for determining chloride and sulfate in denatured ethanol samples according to ASTM D7319 is presented.

Quality and process control of biofuels require straightforward, fast and accurate analysis methods. Ion chromatography (IC) is at the leading edge of this effort. Traces of anions in a gasoline/ethanol blend can accurately be determined in the sub-ppb range after Metrohm Inline Matrix Elimination using anion chromatography with conductivity detection after sequential suppression. While the analyte anions are retained on the preconcentration column, the interfering organic gasoline/bioethanol matrix is washed away.Detrimental alkali metals and water-extractable alkaline earth metals in biodiesel are determined in the sub-ppm range using cation chromatography with direct conductivity detection applying automated extraction with nitric acid and subsequent Metrohm Inline Dialysis. Unlike high-molecular substances, ions in the high-ionic strength matrix diffuse through a membrane into the low-ionic water acceptor solution. In biogas reactor samples, low-molecular-weight organic acids stem from the biodegradation of organic matter. Their profile allows important conclusions concerning conversion in the anaerobic digestion reaction. Volatile fatty acids and lactate can be accurately determined by using ion-exclusion chromatography with suppressed conductivity detection after inline dialysis or filtration.

Several testing methods such as the determination of the acid and the iodine numbers in biodiesel as well as the quantification of sulfate and chloride in bioethanol are described.

The presence of copper in fuel ethanol blends has gained considerable attention, since Cu2+ catalyzes oxidative reactions in gasoline leading to a deterioration of olefins and the formation of gum. Anodic stripping voltammetry (ASV), one of the most sensitive and accurate techniques for trace-metal analysis, has been demonstrated for the determination of Cu(II) in ethanol/gasoline blends without any sample pretreatment. Copper ions are first electrodeposited onto the surface of a hanging mercury drop electrode (HMDE) before the amalgamated copper is quantitatively stripped (anodically dissolved), a current-voltage curve being recorded.Experimental conditions such as deposition time and potential as well as the suitable electrolyte and reference electrode were determined in preliminary experiments. For synthetic samples spiked with Cu2+ (5…100 µg/L), recovery rates between 96 and 112% were obtained. The copper-spiked E85 sample provided a recovery of 100%. The relative standard deviations for Cu2+ concentrations of 5 µg/L and above were 8.0 and 5.5% respectively. Using a preconcentration time of 60 s at -0.7 V versus Ag/AgCl, a linear range of 0…500 µg/L with a detection limit of 2 µg/L was obtained.

This poster provides an overview of ion chromatographic methods combined with inline sample preparation for the determination of anions and water-extractable cations in biofuels. In addition, the determination of the oxidation stability is described.

This poster describes the water determination in different biodiesel samples via direct coulometric titration, the Karl Fischer oven method and an automated KF pipetting system.

Carbonyl compounds (CC) occur in many products, such as bio-oils and fuels, cyclic and acyclic solvents, flavors and mineral oils. Carbonyl compounds can be responsible for the instability of these products during storage or processing. Especially pyrolysis bio-oils are known to cause issues during storage, handling and upgrading. This bulletin describes an aqueous and a non-aqueous analytical titration method for the determination of carbonyl compounds by potentiometric titration.

Determination of traces of lithium, sodium, ammonium, potassium, calcium, and magnesium in ethanol using cation chromatography with direct conductivity detection after Metrohm Inline Matrix Elimination.

Determination of potassium, magnesium, and calcium in biodiesel using cation chromatography with direct conductivity detection applying automated extraction and subsequent Metrohm Inline Dialysis.

Palm oil is a vegetable oil that is used not only in the food industry but also for the manufacture of soaps and body care products. It is furthermore an important raw material for the generation of biodiesel. Depending on the degree of refinement, palm oil can be red, reddish or even colorless in appearance. The carotenes responsible for the color are removed during refinement and the oil becomes increasingly clear. In this Note, the chlorine and sulfur content of various palm oils are determined using Combustion IC.Keyword: pyrohydrolysis

Determination of Total Acid Number (TAN) values in biodiesel to <0.05 mg KOH/g sample.

This Application Note shows that visible near-infrared spectroscopy (Vis-NIRS) can determine water content in ethanol-hydrocarbon blends. Vis-NIRS is a fast alternative to conventional lab methods: it accelerates raw material inspection, process monitoring, and final product control.

The production of biofuels from renewable feedstock has grown immensely in the past several years. Bioethanol is one of the most interesting alternatives for fossil fuels, since it can be produced from raw materials rich in sugars and starch. Ethanol fermentation is one of the oldest and most important fermentation processes used in the biotechnology industry. Although the process is well-known, there is a great potential for its improvement and a proportional reduction in production costs. Due to the seasonal variation of feedstock quality, ethanol producers to need to monitor the fermentation process to ensure the same quality product is achieved. Near-infrared spectroscopy (NIRS) offers rapid and reliable prediction of ethanol content, sugars, Brix, lactic acid, pH, and total solids at any stage of the fermentation process.

Determination of formate, acetate, propionate, isobutyrate, butyrate, isovaleriate, valeriate, and capronate using ion-exclusion chromatography with suppressed conductivity detection after inline dialysis.

Biodiesel or green diesel is manufactured from fats and vegetable oils through ester interchange of the triglycerides they contain, during which glycerin accumulates as byproducts in both free and bonded forms. These accelerate fuel ageing and lead to deposits and clogged filters, which is why maximum permissible highest concentrations have been established (in the US in ASTM D6751 and in the EU in EN 14214).The two specifications prescribe the ion chromatography determination of free and bonded glycerin. This Note describes the determination with the aid of the Metrosep Carb 2 - 150/4.0 column in accordance with ASTM D7591.

In refineries, high octane products are desired since they are used to produce premium gasoline. Catalytic reforming converts heavy naphtha into a high octane liquid product called reformate (a mixture of aromatics and iso-paraffins C7 to C10). The reformate must be constantly monitored to ensure high throughput along the refining process. Traditionally, the octane numbers can be measured by two different methodologies: Inferred Octane Models (IOM) and laboratory octane engine analysis. However, these do not provide «real-time» results and require constant maintenance and human intervention to adapt to current operation conditions. «Real-time» analysis of the octane number in fuels can be performed online via near-infrared spectroscopy (NIRS) technology, which fits well within the international standards (ASTM). Utilization of a Metrohm Process Analytics NIRS XDS Process Analyzer (ATEX version) in conjunction with a sample preconditioning system makes analysis of the octane number simple, fast, and reliable, allowing quick adjustments to the process for a better quality product and higher profitability.

Many fermentation quality parameters can be monitored simultaneously directly in the tank with inline near-infrared spectroscopy, such as the 2060 The NIR Analyzer.

In this Application Note, the 893 Professional Biodiesel Rancimat measures the oxidation stability of biodiesel (or fatty acid methyl esters, FAME), an eco-friendly fuel.

Sustainable biodiesel can be blended with petroleum diesel. The 893 Professional Biodiesel Rancimat measures the oxidation stability of biodiesel and its blends.

Determination of sulfate in an ethanol sample used as an additive for gasoline using anion chromatography with conductivity detection after chemical suppression.

Determination of chloride and sulfate in ethanol using anion chromatography with conductivity detection after chemical suppression.

Determination of fluoride, acetate, formate, nitrate, and sulfate in a gasoline/bioethanol mixture (85% gasoline, 15% ethanol) using anion chromatography with conductivity detection after sequential suppression and Metrohm Inline Matrix Elimination.

Determination of fluoride, acetate, formate, chloride, nitrite, nitrate, phosphate and sulfate in an E85 mixture (85% ethanol and 15% gasoline) by means of anion chromatography with conductivity detection and sequential suppression. The Inline Matrix Elimination serves as sample preparation.

The pHe is a measure of acid strength in alcohol fuels and in ethanol. It can be used as predictor of the corrosion potential of an ethanol-based fuel. The determination of the pHe is preferred over the total acidity, because total acidity overestimates the contribution of weak acids (e.g., carbonic acid) and underestimates the contribution of strong acids (e.g., sulfuric acid). Furthermore, the acid strength is an important parameter to determine in order to reduce the risk of failing motors.This Application Note describes the determination of the pHe value using the 913 pH Meter and the EtOH Trode according to ASTM D6423, which covers denatured fuel ethanol and ethanol fuel blends.

The pHe value is an indicator for the acid strength and shows the presence of strong acids or bases in ethanol. In Europe, ethanol is used as a blending component in gasoline and needs to have a pHe value between 6.5 and 9.0.This Application Note describes a fast and accurate determination of the pHe value using the EtOH-Trode.

Compounds with carbonyl groups can be prone to oxidation for which reason their stability often decreases during storage or processing. The method presented here is suitable for the determination of aldehydes and ketones sparingly soluble in water.Samples are dissolved in deionized water. After a reaction with the hydroxylamine hydrochloride at 50 °C, carbonyl groups are quickly and accurately determined by potentiometric titration using the dUnitrode and sodium hydroxide as titrant.

Carbonyl compounds occur in many products such as bio-oils and fuels, solvents, flavors, and mineral oils. Carbonyl compounds are often prone to oxidation and thus their content has an influence on stability during storage or processing. Especially for pyrolysis bio-oils, stability issues are observed during storage, handling, and upgrading.Oils are dissolved in isopropanol. After a reaction with the hydroxylamine hydrochloride at 50 °C, a fast and accurate determination by potentiometric titration using the dSolvotrode and tetra-n-butylammonium hydroxide as titrant is performed.

Denatured fuel ethanol may contain additives such as corrosion inhibitors and detergents as well as contaminants from manufacturing that can affect the acidity of produced ethanol fuel. An increased acid content in solvents could lead to a variety of problems like a shorter storage stability or chemical corrosion. Using the Optrode with phenolphthalein as indicator, the acidity is determined as acetic acid by titration with sodium hydroxide as titrant.

Denatured fuel ethanol may contain additives such as corrosion inhibitors and detergents as well as contaminants from manufacturing that can affect the acidity of produced ethanol fuel. An increased acid content in solvents could lead to a variety of problems like a shorter storage stability or chemical corrosion.Using the dSolvotrode for indication, the acidity is determined as acetic acid by titration with sodium hydroxide as titrant.

Ethanol, bio-ethanol and biofuel (E85) are increasingly used as substitutes for petroleum-based fuels. During storage, they often come into contact with metallic substrates or surfaces, e.g., in barrels, tanks, or other containers. Excessive concentrations of ions in the stored fuel promotes corrosion. Monitoring the total concentration of the ions present in the fuel matrix should be the first step of an effective anti-corrosion strategy.An easy, fast, and cost-effective method to determine the total amount of ions is by measuring the electrical conductivity according to DIN 15938.

Zn and Pb are determined by anodic stripping voltammetry (ASV) in acetate buffer at pH 4.6.

Iron can be determined in ethanol by adsorptive stripping voltammetry (AdSV) at the HMDE. PIPES buffer is used as supporting electrolyte and catechol as complexing agent at a pH value of 7.0.

The presence of copper in fuel ethanol blends has gained considerable attention since Cu2+ catalyzes oxidative reactions in gasoline leading to olefin decomposition and gum formation. Cu2+ in ethanol can easily be determined using anodic stripping voltammetry (ASV) in ethanol/gasoline blends without any sample pretreatment.

Enhance quality control in material and chemical production with NIRS. Fast, cost-effective, and no sample prep needed. Learn more in our eBook.

The introduction of the ASTM D7591 standard in 2012 marks the establishment of ion chromatographic glycerol determination with pulsed amperometric detection as the official method for biodiesel quality controls. This article describes the rapid and precise analysis of this ASTM method.

Underestimation of quality control (QC) processes is one of the major factors leading to internal and external product failure, which have been reported to cause a loss of turnover between 10–30%. As a result, many different norms are put in place to support manufacturers with their QC process. However, time to result and the associated costs for chemicals can be quite excessive, leading many companies to implement near-infrared spectroscopy (NIRS) in their QC process. This paper illustrates the potential of NIRS and displays cost saving potentials up to 90%.

The FOS/TAC value is an important characteristic to assess the status of the fermenter before costly problems arise. The new Eco Titrator from Metrohm allows the determination of this quotient in a fast, cost-efficient, and precise way.

Knowledge of the water content in lubricating oils, additives, and similar products is important in the manufacturing, purchase, sale, or transfer of petroleum products to help estimate their quality and performance characteristics. Monitoring the water content in such products can prevent damage to infrastructure and ensure safe operation by avoiding corrosion processes and subsequent engine wear. This White Paper explains the easy determination of moisture in petroleum samples by coulometric Karl Fischer titration according to the three procedures outlined in ASTM Method D6304. A comparison is given between the procedures to determine which is most suitable for different sample types.

The fermentation of corn starch to produce ethanol is a complex biochemical process that requires monitoring of many different parameters (e.g., solids, pH, sugar profile, glycerol, lactic and acetic acid, and water and ethanol content). Traditional laboratory analysis using primary methods (e.g. Karl Fischer titration) takes about an hour to complete and is a limiting step for increasing plant capacity and efficiency. As a fast and non-destructive analytical technique, near-infrared spectroscopy (NIRS) can replace routine laboratory analysis, decreasing operating costs and increasing plant efficiency and capacity. This White Paper describes the capabilities of the modern analytical method near-infrared (NIR) spectroscopy for monitoring and improving the fermentation process of corn to ethanol.