*Fuel Quality Monitoring by Color Detection DOI: http://dx.doi.org/10.5772/intechopen.86531*

*Color Detection*

as a whole [10].

particulate matter because the combustion process is affected, leading to higher emissions of pollutants and compounds that cause acid rain, like NOx and SOx, as

The biggest detrimental effect of fuel adulteration is on the performance of the vehicle. In 2006, around 95% of vehicle repairs in São Paulo city, Brazil, were directly or indirectly attributable to poor fuel quality. Indeed, it has been estimated that fuel adulteration cost Brazil over 1 billion dollars that year, including 400 million dollars in lost tax revenues, affecting both local and federal budgets [9]. According to the Brazilian newspaper *Estadão*, a study done in 2017 by the Getúlio Vargas Foundation found that 4.8 billion reais is lost in the fuel sector every year to money laundering and tax evasion, with serious knock-on effects on the economy

According to ANP, the agency responsible for monitoring fuel quality in the country, gasoline can be adulterated in multiple ways, such as by the addition of ethanol over the maximum permitted limit or the illicit addition of light and heavy aliphatic and aromatic solvents, which are themselves constituents of gasoline [6]. Gasoline and ethanol are both adulterated with methanol in Brazil, which is not allowed to exceed 0.5% v/v due to its toxicity, but whose low price makes it an attractive adulterant [11]. Meanwhile, the main nonconformity found in diesel in Brazil is a failure to comply with the correct quantity of biodiesel, which is set by ANP at 10% v/v [12]. Petroleum products like fuels are extremely important inputs for economies, industries, and basic everyday activities all around the world. Their importance to governments—whether for geopolitical reasons or because of armed conflicts or economic factors—means they tend to be taxed heavily, which raises their cost to consumers. As a result, adulteration has become a common practice in

In India, kerosene is subsidized, which makes it particularly popular for adulterating gasoline, along with other products like naphtha, rubber solvents, aromatics, ethanol, light and heavy aliphatic solvents, and lubricants [2, 14, 15]. In 2018, the Petroleum Institute of East Africa announced that up to 75% of the 33 million liters of kerosene consumed every month ends up contaminating diesel and gasoline: only 5 million liters is actually used every month for lighting and cooking [16].

Cases of gasoline adulteration with acetone and sec-butyl acetate were reported in Vietnam and China in 2016, although this practice is less widespread in Vietnam now with the introduction of new limits for ketones in its gasoline specifications. In China, gasoline is often adulterated with substances like naphtha, ethanol, metha-

In France, the most common form of adulteration consists of the addition of soybean oil or used cooking oil to diesel. In the last 5 years, the European Commission has invested heavily in preventing fuel adulteration [18].

According to Mani et al. (2017), the parameters that affect which adulterants are used in fuels—including considerations such as profitability, availability, and chemical compatibility—vary from place to place. The main adulteration methods are blending small quantities of middle distillate fuels like diesel and kerosene in gasoline; blending waste lubricants in gasoline and diesel, because the lubricants are expensive to dispose of in compliance with environmental standards; and adding

In Australia, the Department of the Environment and Energy regulates the Fuel Quality Standards Act 2000, which legislates and provides the standards on fuel quality in the country. In Europe, mandatory quality requirements for automotive

In the United States, ASTM International publishes standards on each type of fuel. Responsibility for setting the standards for fuel quality lies with

well as CO, which is highly asphyxiating [4, 7, 8].

regions as diverse as South America and South Asia [13].

nol, and even silicon oil or waste chemicals containing silicon [17].

small quantities of heavier fuel oils to diesel [3].

gasoline and diesel are laid down by Directive 98/70/EC.

**86**

the Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants. Meanwhile, in Japan there are two standards for fuels: the mandatory standards set by the Central Environment Council, under the Ministry of the Environment, and the Japanese Industry Standards. The former are statutory requirements and regulate the Act on Quality Control for Gasoline and Other Fuels, which has been enforced since April 1996 [19]. **Tables 1**–**4** showing the gasoline, diesel, ethanol, and biodiesel specifications for each country or region are included in the **Supplementary Material**.


### **Table 1.**

*Gasoline specification.*


### **Table 2.**

*Diesel fuel specification.*


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(500 mg kg<sup>−</sup><sup>1</sup>

**Table 4.**

*Biodiesel fuel specification.*

tion systems.

*Fuel Quality Monitoring by Color Detection DOI: http://dx.doi.org/10.5772/intechopen.86531*

capacity to detect fuel adulteration in the field.

diesel S10 (containing 10 mg kg<sup>−</sup><sup>1</sup>

Analytical methods for monitoring gasoline and diesel adulteration were the target of a recent review [2], emphasizing the determination of their different properties, such as density, distillation curve, octane rating, vapor pressure, etc., using physicochemical methods and chromatographic and spectroscopic techniques. Nondestructive analytical methods for identifying off-spec levels of biodiesel in diesel-biodiesel blends and adulteration of the blend have also been covered in a recent review [20], focusing on first-order multivariate calibration models. In this chapter, different colorimetric techniques that can be used in fuel quality control are addressed, especially simple, rapid, low-cost methods that have the potential

**2. Colorimetric methods for monitoring fuel quality in laboratories**

ries in Brazil are visual color, ASTM color, and the copper strip corrosion test. In Brazil, hydrous ethanol should be colorless, while anhydrous ethanol has an orange dye added to it. This difference is designed to prevent the kind of fraud known as "wet ethanol," whereby fraudsters acquire anhydrous ethanol directly from the plants that produce it, evading taxes, then mix it with water, and sell it on as hydrous ethanol. Regular gasoline, additized gasoline, and premium gasoline can be told apart visually by their color: regular gasoline ranges from colorless to yellow, while the other two are colored with a dye, which may be of any color but blue (which is reserved for aviation fuel), but which is normally green for additized and purple for premium [11, 21]. All the dye does is enable the two products to be distinguished from one another; it has no effect on their specifications. Meanwhile,

The colorimetric assays used on a routine basis in fuel quality control laborato-

sulfur) is dyed red to prevent incorrect refueling with this diesel,

whose high sulfur level means it could cause damage to vehicles with more sophisticated engine technologies like selective catalytic reduction or exhaust gas recircula-

sulfur) is naturally yellow in color, while S500

### **Table 3.** *Ethanol fuel specification.*
