Concentration measurement explained
In the essential task of measuring concentration in liquids, the industry uses sophisticated products that guarantee the precision and efficiency of analytical processes. Understanding the exact composition of a solution (whether in pharmaceutical manufacturing, food technology or chemical processing) is made possible by advanced sensor technology that enables accurate concentration detection based on refractometric, potentiometric or spectroscopic principles.
These products, equipped with intelligent interfaces for data transmission and evaluation, offer the possibility of optimizing processes with low maintenance and a long service life, and thus represent an indispensable resource in quality control and process control.
The ultrasonic measuring method from LiquiSonic
The basis of the measuring method is a time measurement that can be realized very precisely and with long-term stability. The concentration or density of a liquid is calculated from the speed of sound. However, other parameters can also be determined, such as the Brix content, the solids content, the dry mass or the suspension density.
Our LiquiSonic® concentration and density meters are used in various processes for analyzing liquids.
In a typical case, a calibration curve is determined from the relationship between the speed of sound and the concentration. On this basis, the corresponding concentration is calculated from each measured sonic velocity value.
Our ultrasonic measuring devices have no mechanical parts that can wear out or age. They have outstanding advantages over competing measurement methods for determining concentration and density.
High reliability in determining the concentration of substances
The measuring method only requires precise time measurement to determine the concentration of the substance . The speed of sound is calculated from the sound propagation time and the known distance between the transmitter and receiver. The typical sensor design includes transmitter and receiver in a compact housing.
Thanks to the sensors, the measuring method is independent of the conductivity, color and transparency of the liquid and is characterized by a high degree of reliability in determining the substance concentration . The measuring accuracy of the devices is between 0.05 m% and 0.1 m%. In addition to sonic velocity measurement, all LiquiSonic® sensors have integrated temperature measurement for temperature compensation in the process.
Basics of concentration measurement
Determining the concentration of different liquids plays a key role in numerous procedures for different processes. The ratio of two substances to each other in a mixture or solution is measured and evaluated.
A central factor in this concentration measurement is the substance concentration. It is defined as the quantity of a substance per unit volume and is particularly important when analyzing solutions. It enables an exact assessment of the chemical composition and reactivity. This makes the concentration of substances an indispensable tool in many areas.
In addition, there are various measuring ranges that make it possible to measure the concentration of substances in different ways. They considerably expand the possibilities of concentration measurement and increase flexibility with regard to the specific requirements of the mixture or solution to be analyzed.
Finally, the amount of liquid to be analyzed plays an important role. It must be sufficient to enable accurate measurement, but not so large that it distorts the measurement result or unnecessarily complicates the measurement.
An important aspect of concentration measurement is the concentration of substances (molarity) in a solution, which is defined as the amount of a substance per unit volume. This is particularly relevant when analyzing a solution , where the molar concentration is crucial for assessing the chemical composition, concentrations and reactivity. Accurately measuring the concentration of a substance in a solution is critical to controlling processes, ensuring quality and conducting scientific research.
Applications of concentration measurements
Concentration measurement is one of the essential methods for analyzing the quality and safety-relevant characteristics of products and substances. It therefore plays a crucial role in several industries. There are various methods for measuring the concentration of a substance in a solution, depending on the type of substance and the requirements of the application.
A practical example of the use of concentration measurement can be found in the pharmaceutical industry, where the precise determination of the concentration of an active ingredient in drugs is essential to ensure their efficacy and safety. This shows the importance of precise measurement methods for determining the concentration of a substance quantity in quality assurance.
Examples for the measurement of a substance concentration
Concentration detection is used in the following areas, for example:
Chemistry/chemical production (for monitoring the composition of mixtures)
Pharmaceutical industry (e.g. for the production of medicines)
Food production (to control the product quality of food)
Metallurgy (to check the quality of metal ores)
Environmental analysis (to calculate pollutants in water)
In addition, concentration measurement is also commonly used in other areas, for example within industry and science.
Method for concentration measurement
The precise determination of the concentration of substances in liquids is of crucial importance for numerous scientific, industrial and medical applications. Different concentration measurement methods are used to quantify the exact content of a substance in a specific volume of liquid
These methods range from spectrophotometric techniques to chromatographic analyses and electrochemical measurements. The selection of the appropriate method depends on the properties of the substance to be analyzed, the requirements of the respective application and the available resources. There are various methods for measuring the concentration of solutions. Each of these measuring methods for determining the concentration of substances has its own advantages and disadvantages.
Refractiometry
The refractometer determines the refractive index of solutions and solids to measure the concentration. The determination of the refractive index is based on the refraction of light that is reflected or refracted by a liquid. Depending on the type and concentration of the dissolved substances, the light is refracted differently.
Consequently, the refractive index results from the concentration of the dissolved substances. An optical sensor (window) measures the reflection of a light beam that is reflected by an LED light source after it hits the sample. The refractometry method is extremely sensitive to influencing factors such as vibrations and requires extremely extensive and time-consuming calibration and regular maintenance.
Radiometry
Radiometry uses radioactive radiation to detect concentrations of a substance. A radioactive preparation sends its radiation through the measuring container, which is received by the detector. A scintillator converts the radioactive radiation into flashes of light and evaluates their number. As the penetration of the gamma rays depends on the substance, the density of the mass is determined from the intensity of the incoming radiation.
Gravimetry
Gravimetry measures the mass concentration by measuring the mass of a substance before and after a chemical reaction. It is used to determine the concentration of a specific element or compound in a sample. The basic process for determining the mass concentration of a substance involves the steps of precipitation, filtration and weighing. This process is extremely time consuming and typically requires large samples . In addition, the measurement principle is very prone to errors as it requires several manual process steps when defining the concentration of the substance.
Titration
Concentration measurement by titration is carried out by adding a solution with a known concentration value to a solution with an unknown concentration value until a chemical reaction occurs. This method is only suitable for certain solutions and is prone to errors when calculating the mass concentration due to manual handling.
Spectrophotometry for concentration measurement
In spectrophotometry, the volume of the sample plays a decisive role in determining the volume concentration of a substance quantity. The volume concentration is a unit of measurement for the quantity of a substance in a mixture in relation to the total volume of the mixture. It indicates what proportion of the total volume of a mixture consists of a particular substance.
Light absorption, which is a key measurement in this method, can be significantly influenced by the volume of the sample. Therefore, accurate determination and control of the sample volume is essential for precise measurement results. Spectrophotometry is suitable for a wide range of samples, including liquids, gases and solid materials.
This method of measuring particle volumes is highly susceptible to interfering factors that affect the accuracy of the sample.
Chromatography (such as HPLC, GC)
Chromatography separates components of a mixture based on their interactions with a stationary and a mobile phase.
There are also other measurement methods/processes that can be used to measure concentrations in certain scenarios. These include
Electrochemical methods (such as potentiometry, ion-selective electrodes)
pH measurement
NMR spectroscopy
Mass spectrometry
Selection criteria for concentration measurement methods
The selection of a suitable method for measuring concentration in liquids depends on several factors, including
Specificity of the application: The type of substances to be measured and the complexity of the solution.
Accuracy and sensitivity: Required precision and ability to detect minimum concentrations .
Speed and throughput: Need for fast measurement results and ability to handle large sample volumes.
Cost-effectiveness: Acquisition and operating costs of equipment and maintenance requirements.
Ease of use: Ease of operation and maintenance, especially in environments with few specialized personnel.
Density and speed of sound of some liquids
| Liquid | Chemical formula | T [°C] |
| v [m/s] | |
| Acetal | CH3CH(OC2H5)2 | 24 | 1,03 | 1378 | |
| Acetic acid ethyl ester | CH4 CO.CH4 COOH2H5 | 25 | 1,021 | 1417 | |
| Acetone | CH3CO.CH3 | 20 | 0,7992 | 1192 | |
| Diethyl ester of acetonedicarboxylic acid | C.(CH2COOC2H5)2 | 22 | 1,085 | 1348 | |
| Acetonitrile | CH3CN | 20 | 0,783 | 1304 | |
| Acetonylacetone | C6H10O2 | 20 | 0,971 | 1416 | |
| Acetophenone | C6H5.CO.CH3 | 20 | 1,026 | 1496 | |
| Acetylacetone | C5H8O2 | 20 | 0,97 | 1383 | |
| Acetyl chloride | C2H3OCl | 20 | 1,103 | 1060 | |
| Acetylene dichloride (cis) | CHCl = CHCl | 25 | 1,262 | 1025 | |
| Acetylene tetrabromide | CHBr2.CHBr2 | 20 | 2,963 | 1041 | |
| Acetylene tetrachloride | CHCl2.CHCl2 | 28 | 1,578 | 1155 | |
| Acrolein | C3H4O | 20 | 0,841 | 1207 | |
| CH2.CH2.COOC2H5 | 22 | 1,013 | 1376 | ||
| Diethyl ester of adipic acid | | | ||||
| CH°2CH2.COOC2H5 | |||||
| CH2CH2COOCH3 | 22 | 1,067 | 1469 | ||
| Dimethyl ester of adipic acid | | | ||||
| CH2CH2COOCH3 | |||||
| Ammonium nitrate 10% | NH4NO3 | 20 | 1540 | ||
| Allyl chloride | CH2CH . CH2CCl | 28 | 0,937 | 1088 | |
| Formic acid | HCOOH | 20 | 1,212 | 1287 | |
| Isoamyl ether | C5H11OC5H11 | 26 | 0,774 | 1153 | |
| Amyl alcohol (n) | C5H11OH | 20 | 0,816 | 1294 | |
| Amyl alcohol (tert.) | (CH3)2C(OH)C2H5 | 28 | 0,809 | 1204 | |
| Amyl acetate | CH3COOC5H11 | 26 | 0,875 | 1168 | |
| Amyl bromide (n) | C5H11Br | 20 | 1,223 | 981 | |
| Amyl formate | HCOOC5H11 | 26 | 0,869 | 1201 | |
| Aniline | C6H5NH2 | 20 | 1,022 | 1656 | |
| Ascorbic acid 30% | C6H8O6 | 20 | 1578 | ||
| Barium sulfide 120 g/l | BaS | 50 | 1591 | ||
| Benzaldehyde | C7H6O | 20 | 1,046 | 1479 | |
| Benzene | C6H6 | 20 | 0,878 | 1326 | |
| Benzoyl chloride | C6H5COOCl | 28 | 1,211 | 1318 | |
| Benzylacetone | C10H12O | 20 | 0,989 | 1514 | |
| Benzyl alcohol | C7H7OH | 20 | 1,045 | 1540 | |
| Benzyl chloride | C7H7Cl | 20 | 1,098 | 1420 | |
| Diethyl ester of succinic acid | (CH2-COOC2H5)2 | 22 | 1,039 | 1378 | |
| Boric acid 5% | H3BO3 | 30 | 1520 | ||
| Tartaric acid | COCH3COOH | 20 | 1,267 | 1471 | |
| Bromal | C2HOBr3 | 20 | 2,55 | 966 | |
| Bromonaphthalene (a) | C10H7Br | 20 | 1,487 | 1372 | |
| Bromoform | CHBr3 | 20 | 2,89 | 928 | |
| Butyric acid | C3H7COOH | 20 | 0,959 | 1203 | |
| Butyl alcohol (n) | C4H9OH | 20 | 0,81 | 1268 | |
| Isobutyl alcohol (iso) | (CH3)2CHCH2OH | 20 | 0,802 | 1222 | |
| Tertiary butyl alcohol (tert.) | C4H10O | 20 | 0,789 | 1155 | |
| Butyl acetate (n) | CH3COOC4H9 | 26 | 0,871 | 1271 | |
| Butyl bromide (n) | CH3(CH2)2CH2Br | 20 | 1,275 | 990 | |
| Butyl chloride (n) | C4H9Cl | 20 | 0,884 | 1133 | |
| 2,3-Butanediol | C4H10O2 | 25 | 1,019 | 1484 | |
| Butyl formate | HCOOC4H9 | 24 | 0,906 | 1199 | |
| Butyl iodide (n) | CH3(CH2)2CH2J | 20 | 1,614 | 977 | |
| Butyllithium | 20 | 1390 | |||
| Caprolactam | C6H11NO | 120 | 1330 | ||
| Caproic acid | C5H11COOH | 20 | 0,929 | 1280 | |
| Caprylic acid | C7H15COOH | 20 | 0,91 | 1331 | |
| Carvacrol | C10H14O | 20 | 0,976 | 1475 | |
| Quinaldine | C10H9N | 20 | 1,069 | 1575 | |
| Quinoline | C9H7N | 20 | 1,093 | 1600 | |
| Chlorobenzene | C6H5Cl | 20 | 1,107 | 1291 | |
| Ethyl chloroacetate | CH2ClCOOC2H5 | 26 | 1,16 | 1234 | |
| Methyl chloroacetate | CH2ClCOOCH3 | 26 | 1,232 | 1331 | |
| Alpha-chloronaphthalene | C10H7Cl | 20 | 1481 | ||
| Chloroform | CHCl3 | 20 | 1,489 | 1005 | |
| Ortho-chlorotoluene | C7H7Cl | 20 | 1,085 | 1344 | |
| Meta-chlorotoluene | C7H7Cl | 20 | 1,07 | 1326 | |
| Para-chlorotoluene | C7H7Cl | 20 | 1,066 | 1316 | |
| Cinnamaldehyde | C9H8O | 25 | 1,112 | 1554 | |
| Citral | C10H16O | 20 | 0,859 | 1442 | |
| Crotonaldehyde | C4H6O | 20 | 0,856 | 1344 | |
| Cyclohexane | C6H12 | 20 | 0,779 | 1284 | |
| Cyclohexanol | C6H12O | 20 | 0,962 | 1493 | |
| Cyclohexanone | C6H10O | 20 | 0,949 | 1449 | |
| Cyclohexene | C6H10 | 20 | 0,811 | 1305 | |
| Cyclohexylamine | C6H13N | 20 | 0,896 | 1435 | |
| Cyclohexyl chloride | C6H11Cl | 20 | 0,937 | 1319 | |
| Cyclopentadiene | C5H6 | 20 | 0,805 | 1421 | |
| Cyclopentanone | C5H#O | 24 | 0,948 | 1474 | |
| 1-Decene | C10H20 | 20 | 0,743 | 1250 | |
| Decyl alcohol (n) | C10H21OH | 20 | 0,829 | 1402 | |
| Decyl chloride (n) | C10H21Cl | 20 | 0,866 | 1318 | |
| Diacetosorbose 50% | 50 | 1557 | |||
| Diacetyl | C4H6O2 | 25 | 0,99 | 1236 | |
| Diethylaniline | C6H5N(C2H5)2 | 20 | 0,934 | 1482 | |
| Diethylene glycol | C4H10O3 | 25 | 1,116 | 1586 | |
| Diethylene glycol ether | C6H14O3 | 25 | 0,988 | 1458 | |
| Diethyl ketone | C2H5COOC2H5 | 24 | 0,813 | 1314 | |
| Dibromoethylene (cis) | CHBr . CHBr | 20 | 2,246 | 957 | |
| Dibromoethylene (trans) | CHBr . CHBr | 20 | 2,231 | 936 | |
| Dichloroethane | C2H4Cl2 | 20 | 1,253 | 1034 | |
| Dichloroethylene (cis) | CHCl CHCl | 20 | 1,282 | 1090 | |
| Dichloroethylene (trans) | CHCl CHCl | 20 | 1,257 | 1031 | |
| Dichlorobenzene (m) | C6H4Cl2 | 28 | 1,285 | 1232 | |
| Dichlorobenzene (o) | C6H4Cl2 | 20 | 1.305 | 1295 | |
| Diethylene glycol diethyl ether | O(CH2COOC2H5)2 | 22 | 1,433 | 1435 | |
| Dimethylamine, DMA 60% | (CH3)2NH | 20 | 0,826 | 1430 | |
| Dimethylaniline | C8H11N | 20 | 0,956 | 1509 | |
| Dimethylacetamide 90% | C4H9NO | 20 | 0,94 | 1550 | |
| Dimethylbenzoate | |||||
| Dimethylformamide, DMF | C3H7NO | 20 | 0,948 | ||
| Dimethylglutaric acid | C(CH3)2(COOC2H)2 | 24 | 1,038 | 1371 | |
| dimethyl ester | |||||
| Dioxane | C4H8O2 | 20 | 1,038 | 1389 | |
| Dipentene | C10H16 | 24 | 0,864 | 1328 | |
| Diphenyl ether | C6H5OC6H5 | 24 | 1,072 | 1469 | |
| Diphenylmethane | C6H5 - CH2 - C6H5 | 28 | 1,006 | 1501 | |
| Di-n-propyl ether | C6H14O | 20 | 0,747 | 1112 | |
| n-Dodecyl alcohol | C12H25OH | 30 | 0,827 | 1388 | |
| Iron(II) sulfate | FeSO4 | 20 | 1,9 | ||
| Elaidic acid | C18H34O2 | 45 | 0,873 | 1346 | |
| Acetic acid | CH3COOH | 20 | 1,049 | 1150 | |
| Acetic anhydride | (CH3CO)2O | 24 | 1,975 | 1384 | |
| Ethyl ether | C4H10O | 20 | 0,714 | 1008 | |
| Ethyl alcohol | C2H5OH | 20 | 0,789 | 1180 | |
| Ethyl acetate | CH3COOC2H5 | 20 | 0,9 | 1176 | |
| Ethylene oxide | C2H4O | 26 | 0,892 | 1575 | |
| Ethylbenzene | C6H5.C2H5 | 20 | 0,868 | 1338 | |
| Ethylbenzylaniline | C15H17N | 20 | 1,029 | 1586 | |
| Ethyl bromide | C2H5Br | 28 | 1,428 | 892 | |
| Ethyl butyrate | C3H7 . COOC2H5 | 24 | 0,877 | 1171 | |
| Ethyl caprylate | CH3(CH2)6COOC2H5 | 28 | 0,872 | 1263 | |
| Ethylene bromide | C2H4Br2 | 20 | 2,056 | 1009 | |
| Ethylene chloride | CH2Cl . CH2Cl | 23 | 1,255 | 1240 | |
| Ethylene glycol | C2H6O2 | 20 | 1,115 | 1616 | |
| Ethyleneimine | C2H5N | 24 | 0,8321 | 1395 | |
| Ethyl formate | H . COOC2H5 | 24 | 1,103 | 1721 | |
| Ethyl iodide | C2H5J | 20 | 1,94 | 869 | |
| Ethyl carbonate | CO(OC2H5)2 | 28 | 0,977 | 1173 | |
| Ethyl phenyl ketone | C9H10O | 20 | 1,009 | 1498 | |
| Ethyl phthalate | C6H4(COOC2H5)2 | 23 | 1,121 | 1471 | |
| Ethyl propionate | C2H5COOC2H5 | 23 | 0,884 | 1185 | |
| Hydrofluoric acid | HF | 0 | 1,2 | 1362 | |
| Formaldehyde 60% | CH2O | 85 | 1,103 | 1516 | |
| Formamide | CH3NO | 20 | 1,139 | 1550 | |
| Furoic acid | C4H4O4 | 20 | 1,051 | 1303 | |
| Furfuryl alcohol | C5H6O2 | 25 | 1,135 | 1450 | |
| Geranyl acetate | C12H20O2 | 28 | 0,915 | 1328 | |
| Glycerin | C3H8O3 | 20 | 1,261 | 1923 | |
| Hemellitol | C9H12 | 20 | 0,887 | 1372 | |
| Heptane (n) | C7H16 | 20 | 0,684 | 1162 | |
| Heptanone | C7H14O | 20 | 0,814 | 1207 | |
| 1-Heptene | C7H14 | 20 | 0,699 | 1128 | |
| Heptyl alcohol (n) | C7H15OH | 20 | 0,823 | 1341 | |
| Hexamethylene- | 20 | 1,201 | 2060 | ||
| diamine adipate | |||||
| Hexane | C6H14 | 20 | 0,654 | 1083 | |
| Hexyl alcohol (n) | C6H13OH | 20 | 0,82 | 1322 | |
| Hexyl chloride (n) | C6H13Cl | 20 | 0,872 | 1221 | |
| Hexyl iodide (n) | C6H13J | 20 | 1,441 | 1081 | |
| Hydride | C9H10 | 20 | 0,91 | 1403 | |
| Indene | C9H8 | 20 | 0,998 | 1475 | |
| Isopropylbenzene (Cumene) | C6H5CH(CH3)2 | 20 | 0,878 | 1342 | |
| Iodobenzene | C6H5J | 20 | 1,83 | 1113 | |
| Jonone A | C13H20O | 20 | 0,932 | 1432 | |
| Carbolic acid (Phenol) | C6H5OH | 20 | 1,071 | 1520 | |
| Kerosene | 20 | 0,81 | 1301 | ||
| Cresol (o) | C7H8O | 25 | 1,046 | 1506 | |
| Cresol ethyl ether (o) | C6H4(CH3)OC2H5 | 25 | 0,944 | 1315 | |
| Cresol methyl ether (m) | C6H4CH3 OCH3 | 26 | 0,976 | 1385 | |
| Linseed oil | 31 | 0,922 | 1772 | ||
| Linalool | C10H17OH | 20 | 0,863 | 1341 | |
| Lithium bromide | LiBr | 20 | 1612 | ||
| Lithium chloride | LiCl | 20 | 2,068 | ||
| Maleic acid | C4H4O | 20 | 1,068 | 1352 | |
| Diethyl ester of malonic acid | CH2(COOC2H5)2 | 22 | 1,05 | 1386 | |
| Mesitylene | C6H3(CH3)2 | 20 | 0,863 | 1362 | |
| Mesityl oxide | C6H10°O | 20 | 0,85 | 1310 | |
| Methyl ethyl ketone | C4H8O | 20 | 0,805 | 1207 | |
| Methyl alcohol | CH3OH | 20 | 0,792 | 1123 | |
| Methyl acetate | CH3COOCH3 | 25 | 0,928 | 1154 | |
| N-Methylaniline | C7H9N | 20 | 0,984 | 1586 | |
| Methyldiethanolamine, MDEA | C5H13NO2 | 20 | 1,04 | 1572 | |
| Methylene bromide | CH2Br2 | 24 | 2,453 | 971 | |
| 2-Methylbutanol | C5H11OH | 30 | 0,806 | 1225 | |
| Methylene chloride | CH2Cl2° | 20 | 1,336 | 1092 | |
| Methylene iodide | CH2J2 | 24 | 3,233 | 977 | |
| Methylenehexalin | C6H10(CH3)OH | 22 | 0,913 | 1528 | |
| Methylhexyl ketone | CH3COC6H13 | 24 | 0,817 | 1324 | |
| Methylisopropylbenzene (p) | C6H4CH3CH(CH3)2 | 28 | 0,857 | 1308 | |
| Methylisobutylketone, MIBK | C6H12O | 20 | 0,8 | 1220 | |
| Methyl iodide | CH3J | 20 | 2,279 | 834 | |
| Methyl propionate | C2H5COOCH3 | 24 | 0,911 | 1215 | |
| Methyl silicone | 20 | 1030 | |||
| Methylcyclohexane | C7°H14 | 20 | 0,764 | 1247 | |
| Methylcyclohexanol (o) | C7H14O | 26 | 0,922 | 1421 | |
| Methylcyclohexanol (m) | C7H14O | 26 | 0,914 | 1406 | |
| Methylcyclohexanol (p) | C7H14O | 26 | 0,92 | 1387 | |
| Methylcyclohexanone (o) | C7H12O | 26 | 0,924 | 1353 | |
| Methylcyclohexanone (p) | C7H12O | 26 | 0,913 | 1348 | |
| Monochloronaphthalene | C10H7Cl | 27 | 1,189 | 1462 | |
| Monomethylamine, MMA 40% | CH5N | 20 | 0,9 | 1765 | |
| Morpholine | C4H9NO | 25 | 1 | 1442 | |
| Sodium hydroxide | NaOH | 20 | 1,43 | 2440 | |
| Sodium hypochlorite | NaOCl | 20 | 1,22 | 1768 | |
| Sodium iodide | NaJ | 50 | 1510 | ||
| Nicotine | C10H14N2 | 20 | 1,009 | 1491 | |
| Nitroethyl alcohol | NO2C2H4OH | 20 | 1,296 | 1578 | |
| Nitrobenzene | C6H5NO2 | 20 | 1,207 | 1473 | |
| Nitromethane | CH3NO2 | 20 | 1,139 | 1346 | |
| Nitrotoluene (o) | CH3C6H4NO2 | 20 | 1,163 | 1432 | |
| Nitrotoluene (m) | CH3C6H4NO2 | 20 | 1,157 | 1489 | |
| Nonane | C9H20 | 20 | 0,738 | 1248 | |
| 1-Nonene | C9H18 | 20 | 0,733 | 1218 | |
| Nonyl alcohol (n) | C9H19OH | 20 | 0,828 | 1391 | |
| Oleic acid (cis) | C18H34O2 | 45 | 0,873 | 1333 | |
| Oenanthic acid | C6H13COOH | 20 | 0,922 | 1312 | |
| Octane (n) | C8H18 | 20 | 0,703 | 1197 | |
| 1-Octene | C8H16 | 20 | 0,718 | 1184 | |
| Octyl alcohol (n) | C8H17OH | 20 | 0,827 | 1358 | |
| Octyl bromide (n) | C8H17Br | 20 | 1,166 | 1182 | |
| Octyl chloride (n) | C8H17Cl | 20 | 0,872 | 1280 | |
| Olive oil | 32 | 0,904 | 1381 | ||
| Diethyl oxalate | (COOC2H5)2 | 22 | 1,075 | 1392 | |
| Paraldehyde | C6H12O3 | 20 | 0,994 | 1204 | |
| Pentane | C5H12 | 20 | 0,621 | 1008 | |
| Pentachloroethane | C2HCl5 | 20 | 1,672 | 1113 | |
| 1-Pentadecene | C15H30 | 20 | 0,78 | 1351 | |
| Perchloroethylene | C2Cl4 | 20 | 1,614 | 1066 | |
| Phenethyl ether (Phenetol) | C6H5OC2H5 | 26 | 0,774 | 1153 | |
| Pentane | C5H12 | 20 | 0,621 | 1008 | |
| Petroleum | 34 | 0,825 | 1295 | ||
| Beta-phenyl alcohol | C8H9OH | 30 | 1,012 | 1512 | |
| Phenylhydrazine | C6H8N2 | 20 | 1,098 | 1738 | |
| Phenyl methyl ether (Anisole) | C6H5OCH3 | 26 | 1,138 | 1353 | |
| Beta-phenylpropyl alcohol | C9H11OH | 30 | 0,994 | 1523 | |
| Phenyl mustard oil | C6H5NCS | 27 | 1,131 | 1412 | |
| Picolin (a ) | C5H4NCH3 | 28 | 0,951 | 1453 | |
| Picolin (b ) | CH3C5H4N | 28 | 0,952 | 1419 | |
| Pinen | C10H16 | 24 | 0,778 | 1247 | |
| Piperidine | C5H11N | 20 | 0,86 | 1400 | |
| Phosphoric acid 50% | H3PO4 | 25 | 1,3334 | 1615 | |
| Polyvinyl acetate, PVAc | 24 | 1458 | |||
| n-propionitrile | C2H5CN | 20 | 0,787 | 1271 | |
| Propionic acid | CH3CH2COOH | 20 | 0,992 | 1176 | |
| Propyl alcohol (n) | C3H7OH | 20 | 0,804 | 1223 | |
| Propyl alcohol (i) | C3H7OH | 20 | 0,786 | 1170 | |
| Propyl acetate | CH3COOC3H7 | 26 | 0,891 | 1182 | |
| Propyl chloride (n) | C3H7Cl | 20 | 0,89 | 1091 | |
| Propylene glycol | C3H8O2 | 20 | 1,432 | 1530 | |
| Propyl iodide | C3H7J | 20 | 1,747 | 929 | |
| Pseudobutyl-m-xylene | C12H18 | 20 | 0,868 | 1354 | |
| Pseudocumol | C9H12 | 20 | 0,876 | 1368 | |
| Phthalic anhydride | C6H4-(CO)2O | 20 | 1,527 | ||
| Pyridine | C6H5N | 20 | 0,982 | 1445 | |
| Mercury | Hg | 20 | 13,595 | 1451 | |
| Resorcinol dimethyl ether | C6H4(OCH3)2 | 26 | 1,054 | 1460 | |
| Resorcinol monomethyl ether | C6H4OH OCH3 | 26 | 1,145 | 1629 | |
| Salicylaldehyde | OH C6H4CHO | 27 | 1,166 | 1474 | |
| Methyl salicylate | OHC6H4COOCH3 | 28 | 1,18 | 1408 | |
| Hydrochloric acid 35% | HCl | 20 | 1,1738 | 1510 | |
| Carbon disulfide | CS2 | 20 | 1,263 | 1158 | |
| Sulfuric acid 90% | H2SO4 | 20 | 1,814 | 1455 | |
| Tetraethylene glycol | C8H18O5 | 25 | 1,123 | 1586 | |
| Tetrabromoethane | C2H2Br4 | 20 | 2,963 | 1041 | |
| Tetrachloroethane | C2H4Cl | 20 | 1,6 | 1171 | |
| Tetrachloroethylene | C2Cl4 | 28 | 1,623 | 1027 | |
| Carbon tetrachloride | CCl4 | 20 | 1,595 | 938 | |
| Tetrahydrofuran, THF | C4H8O | 20 | 0,889 | 1304 | |
| Tetralin | C10H12 | 20 | 0,967 | 1492 | |
| Tetranitromethane | CN4O8 | 20 | 1,636 | 1039 | |
| Thiodiglycolic acid diethyl ester | S(CH2COOC2H5)2 | 22 | 1,142 | 1449 | |
| Thioacetic acid | C2H4OS | 20 | 1,064 | 1168 | |
| Thiophene | C4H4S | 20 | 1,065 | 1300 | |
| Toluidine (o) | C7H9N | 20 | 0,998 | 1634 | |
| Toluidine (m) | C7H9N | 20 | 0,989 | 1620 | |
| Toluene | C7H8 | 20 | 0,866 | 1328 | |
| Transformer oil | 32 | 0.895 | 1425 | ||
| Triethylene glycol | C6H14O4 | 25 | 1,123 | 1608 | |
| Trichloroethylene | C2HCl3 | 20 | 1,477 | 1049 | |
| 1,2,4-Trichlorobenzene | C6H3Cl3 | 20 | 1,456 | 1301 | |
| 1-Tridecene | C13H26 | 20 | 0,767 | 1313 | |
| Trimethylene bromide | C3H6Br2 | 23,5 | 1,977 | 1144 | |
| Triolein | C3H5(C18H33O2)3 | 20 | 0,92 | 1482 | |
| 1-Undecene | C11H22 | 20 | 0,752 | 1275 | |
| Valeric acid | C4H9COOH | 20 | 0,942 | 1244 | |
| Vinyl acetate, VAc | C4H6O2 | 20 | 0,9317 | 900 | |
| Water | H2O | 25 | 0,997 | 1497 | |
| Xylene (o) | C8H10 | 20 | 0,871 | 1360 | |
| Xylene (m) | C8H10 | 20 | 0,863 | 1340 | |
| Xylene (p) | C8H10 | 20 | 0,86 | 1330 | |
| Citronella oil | 29 | 0,89 | 1076 | ||
| Citric acid 60% | C6H8O7 | 20 | 1686 |
