Tuesday, August 9, 2022

Chemistry Tidbits Episode 5: Classical Vs Modern Analytical Chemistry

i welcome you both to another episode of chemistry bits bite size chemistry concepts this episode.

In this lecture video you know outline of a google sap hana would be uh starting from the introduction to analytical chemistry and then classical analytical chemistry modern instrumental analytical chemistry and some enumeration of the other applications of analytics.

Have you ever thought what's inside your water well the pure form of water is made up of h2o but the water present in nature is oftentimes a mixture water most of the time is a complex mixture with other non-h2o constituents guyanang minerals and ions maybe other organic matter pero panopanadin.

Contains water anguna samples are nectar line and calcium bicarbonate sodium chloride potassium sulfate magnesium and fluoride and silicon some of the uh other non-h2o conspicuous.

In drinking water mayweather minerals demand at ions at recommended levels of course that are good for the body now let us define analytical chemistry it is a branch of chemistry that let us ask what is something made of it lets us know the identity and the quantity of the components in a more technical.

Definition according to american chemical society analytical chemistry is the science of obtaining processing and communicating information about the composition and structure of matter if you can see here in the image jung clown analytical chemistry is linked to other disciplines like in.

Biology physics engineering medicine material science agriculture environmental science geology and even social sciences young men just talking analytical chemistry is about chemical analysis which is very essential in say but analytical chemistry can basically be categorized into two main parts.

The classical and the modern one classical analytical chemistry or classical methods of analysis involves total analytical techniques based on mass and volume rapaljeong chromatography and a lot more now things field.

Is napa if you're going to study analytical chemistry in college it would require you at least two semesters to cover most of the topic but still not all so with that is young basic concepts since meruntoyakibatibang level audience defines.

Important we have the matrix other components in the sample other than the analyte so congratulations analyze a sample in your matrix titrant is a solution of the of known.

Concentration in the breadth where amount of the added titrant is equivalent to the amount of analyte of synaptic endpoint point in titration when physical change occurs associated by chemical equivalence phage or classical analytical methods so nah in an add the new classical analytical.

Chemistry or classical methods of analysis before we introduce the general specifics i would like to highlight some of the important basic concepts in from general chemistry types of reactions balancing chemical equations and most importantly stoichiometric relations and calculations.

Basis numerical analysis small with say the quantity of compound a to compound b now let's kick it off by starting with gravimetry when we say gravimetry these are quantitative methods that are based on mass measurements.

Or change in mass measurements basically we do have two common gravimetric techniques we have precipitation gravimetry and volatilization gravimetry when we say precipitation gravimetry from the word precipitation the analyte is precipitated out from the sample and is converted to a weightable compound with known composition just like in the.

Visualization for precipitation gravimetry you have a sample organic matter in your set up so in this case the great affirmative silver with the chlorine to form silver chloride then silver chloride net precipitate soaked in filtering silver chloride from the.

Sample then you dry it on your way when we say volatilization garbage in a mat the analyte is converted to gas of non-composition visualization you have a sample here just like in this as shown in this visualization you have a sample you weigh it you apply heat to dissipate the analyte you wait again you subtract the before and after to.

Determine the mass of the analyte so an example of precipitation gravimetry is a determination of chloride ions in water so as part of a brief procedure you have to do sample preparation addition of silver nitrate heating and then cooling up on the setup filtering.

Of silver chloride drying up silver chloride precipitate weighing on silver chloride precipitates and stoichiometric calculation just like what i said in the introduction of classical analytical chemistry we do really have to have a good command of types of reaction stoichiometric calculations and chemical equation balancing so as you can see.

Here is that we have chloride ions in the water we add silver nitrate para macaron and single displacement um margarita acting silver atom chloride to form silver chloride and then since in silver chloride is insoluble in water magnum precipitation for volatilization gravimetrinoma determination of water of.

Crystallization and magnesium sulfate times xh2o as part of this brief procedure you do set a preparation you do heating of magnesium sulfate increasible using tripod bunsen burner or oven just like in the picture filling of crucible with sample and.

Desiccator weighing and repeating and recalling until constant weight is achieved and then do stoichiometric calculations documentary calculations that's the very backbone of analytical gains what we're doing in this determination is that we have magnesium sulfate our hydrate then when we say hydrated.

Metal salts crystalline structure non-solid metal we apply heat to release the water from the crystal structure and in the end we would know long water molecules in the crystal structure now the mark on the entire international machine when we say trade symmetry it is.

Based on the volume of the solution of known concentration that is needed to completely react to the analyte tsum kanina gravimetry based on mass contextual titration and is generally based on the volume of the solution we do have three common types of tetrametry you have acid-base digemetry complex symmetrical geometry and redox texture.

Machine so as you can observe jung difference vanilla is in the type of reaction in voldemort so when we say acid-base the symmetry from the word acid base this devoted to various types of neutralization reaction in which analyte and the tritone undergoes acid base reaction oxidability complex symmetric titration.

It involves adding of complexing reagent involves the formation of a complex from ligand in the metal analyte when we say redux the chemical man it involves analytical reactions that make use of redox reactions or electron transfers as an example for acid based extremity is the determination of acetic acid in.

Vinegar swinging termination of acetic acid palette in vinegar is very important enough let's say you have to have the right um the right amount of acetic acid the right amount of concentration of acetic acid in your vinegar parasite for human consumption as part of its brief procedure uh you do sample preparation preparation of the.

Titrand standardization if needed adding of the abrupt most appropriate indicator then dispensing the base sodium in this case sodium hydroxide each flask with sample vinegar until end point record the volume to arrive at the end point and then stoichiometric calculations so what's really happening in acid-base state symmetry in this case is that you.

Have the acetic acid reacting with your sodium hydroxide so what happens when an acid in a base reacts with each other they form salt and water as an example of complex symmetric tissue machine is a determination of hardness of water magnesium and calcium ions in water samples so as a brief procedure you do sample.

Preparation preparation of the nitrogen dispensing of ethane transfus the short term for ethylene diamine acetic acid the endpoint and recording of the volume and stoichiometric calculation what really happens in this digeometric technique is that you have calcium and magnesium ions in your water sample.

Right you put ebt or ericom black tea as the indicator because it is the most appropriate indicator to use in the ph strains and upon adding of the buffer in the ebt become wine red in color when you do the eta titration now and then if you arrive at this color then you reach the end point for the redox titrating demand is.

Determination of vitamin c in commercial tablets by iodimetric method so as part of the brief procedure you do sample preparation preparation of titan and starch indicator standardization of the titrand dispensing of the titrant until the end point and recording of the volume is that this is already the end point.

And then this is just an overran to validate if you have really reached the end point now already now to make you for modern or instrumental analytical chemistry one of the main reasons of the emergence and development of modern analytical chemistry is to cater problems that classical analysis cannot solve especially in sensitive.

Identification and quantification of analytes in complex samples like blood urine plant extracts and others the instrumental analysis nowadays is the go to gold standards for chemical analysis before we proceed with the discussion i would like to lay down some of the important basic concepts when you're when you're studying modern.

And instrumental analytical chemistry which are the following energy absorption and emission electronic transitions bond polarity difference in electronegativity molecular geometries and structures intermolecular forces of attractions so when we say modern instrumental analysis.

In chemical concepts like spectroscopy chromatographic separation are incorporated to sophisticated and specialized instruments for easier and more efficient measurement of the analyte compared to classical methods the analyte is characterized based on the instrument signal measured which provides data.

On for example absorption emission transmittance retention time and peak area chemical shifts etc the values from these can be translated to concentration of analyte or analyzed to provide the structure and identity of the atoms or compound some of the common spectroscopic techniques are atomic spectroscopy this is the.

Actual image of the instrument which is being applied in the analysis of heavy metals from plants soil water and food the main concept of atomic spectroscopy is based on the fact that when you shed a continuous spectrum to an atom it has a unique emission spectrum and absorption spectrum which you can use to identify a certain atom and you can use.

The instrument signal in the quantification of those atomic species now we also have uvs spectroscopy which involves the measurement of absorption of the sample basically what happens here is that you expose the sample in a beam of uvis and then the sample will absorb some of the specific wavelengths depending on.

What chromophores is present in the molecule one of the applications of uv spectroscopy is the analysis of benzoic acid in beverages we also have ir spectroscopy which involves shining iradition to the sample in which the sample would absorb some of the ir radiation it would cause excitation of molecular vibrations and.

Rotations so basically what happens here is that you direct an infrared beam to the sample and then the molecules in the sample would be excited through vibrations now the beam is then absorbed at specific energy of vibration and loses its intensity at corresponding wave number one of the applications of ir.

Spectroscopy is in drug and food fraud analysis still under modern instrumental analytical chemistry is chromatography so we do have two common types of chromatography gas and liquid chromatography so basically when we say chromatography it's just synonymous with separation of the different components in a sample.

Enabled by the different interactions within the column so when dealing with chromatography we have to be acquainted with the concept of mobile base and the stationary phase so when we say mobile base from the from the start of the column to the end of the column which would have an interaction with.

Your sample and would enable the separation of the analytes in the sample now the principle of separation is based on the interactions in the stationary phase so analyte now my less interaction with the stationary face in the column interaction or stronger interaction with.

The stationary phase in union last lab so in gas chromatography you inject a sample in the injector and then the sample will be pushed by a carrier gas to the column and this is what's happening in the column the sample gets separated into its different analytes and then would be detected into the vector and then would be expressed as a.

Chromatogram indeed out in the pc which is in the column speak and then so on and so forth we also have high performance liquid chromatography which uses the same idea with gas chromatography but different languages like in liquid chromatography solvency.

In a garment has moved by phase the same is happening the sum of the injector samples the sample gets separated into its different analytes and would be reflected in the chromatogram of the sample hplc is applied in the analysis of non-volatile compounds such as drugs and beverages etc now we also have other analytical instruments being used in the.

Lab we have nuclear magnetic resonance spectrometer which is used to determine the connectivities of atoms in a molecule especially organic compounds we also have thermal thermal gravimetric analyzer which is used to determine the thermal properties of a compound and we also have mass spectrometer which is used to determine the mass of the ions.

Some of the application of instrumental analytical chemistry as a whole is in environmental monitoring in food and plant analysis and in multi-omics technologies like in the analysis of the dna rna the proteins and the metabolites which is collectively uh termed as omix technologies so the summary we have discussed about classical and modern.

Instrumental analytical chemistry in classical we have techniques including gravimetry in modern demand includes spectroscopy and chromatography in classical government tree is based on mass is generally based on volume measurements in modern instrumental.

Measurement of analyte is based on instrument signal like absorption transmittance emission retention time in classical it's generally cheaper method of analysis but less efficient given a lot of labor and is less used today the modern instrument telemet is more efficient and is of wide applicability but generally.

Mostly so that concludes our discussion for today i hope you learned a lot from this discussion some chemistry internet hub and this is chemistry tidbits bite size chemistry concepts.


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