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Geopolymeric Membrane and its Application in Wastewater Treatment

admin — Sun, 17 Nov 2024 19:46:47 +0000

I am Sana Noor PhD scholar at Abdul Wali Khan University Mardan. My research interests are geopolymer, geopolymeric membrane and magnetic geopolymer composites. I am thankful to IM GROUP OF RESEARCHERS for providing me such opportunity. I believe this content will provide you some knowledge about the geopolymeric membrane and its application in wastewater treatment.

Content Number: 01
Author Name: Sana Noor
Author I’d: SBPWNC – A01
Educational Institution: Abdul Wali Khan University, Mardan, Pakistan
Content Title: Geopolymeric membrane and its application in wastewater treatment

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An overview on Geopolymeric membrane in waste water treatment

This content address introduction of geopolymer, geopolymeric membrane, synthesis and its application. One of the most significant environmental issues of the twenty-first century is a lack of drinking water, which has been driven by global climate change and population expansion. As a result, wetlands that are naturally occurring are disappearing, billions of people continue to live in nations facing water emergencies, and they lack access to clean water, sanitation, and hygiene. However, it is believed that between 50 and 80 percent of effluent is released untreated. Wastewater is viewed as a dependable alternative water supply and a way to address the water issue in the face of rising demand. Sixty percent of the 2030 Sustainable Development Goals depend on effective water management and wastewater treatment. There are mainly three stages

Separation, biological treatment, and purification of wastewater treatment that can be used constantly. Membrane technology is only the one that can be used as a solution in all three stages. The first stage involves the separation of bacteria, oil, fat, and suspended solids, followed by the purification process using micro membranes and the final stage using ultrafiltration or reverse osmosis membranes.

Membranes can be categorized as either organic or inorganic depending on the materials employed in their production. Each and every membrane has some advantages and disadvantages in terms of performance, stability, and synthesis methods. Geopolymers are inorganic substances that are beginning to be considered as potential inorganic membrane building materials.

Introduction to geopolymer

Geopolymer is an alternate form of the traditional Portland cement, which is more ecofriendly to the environment. It is an inorganic synthetic polymers forming a long network of SiO₄ and AlO₄. It is estimated that its emit 0.1 to 0.5 billion tons of CO₂ per year to the environment.

Formation

The process through which geopolymer is formed is known as Geopolymerization, in which alumino- silicate materials are dissolved in an alkali activator solution at room temperature they form a three dimensional network of silico-aluminate.

Role of alkali activator

In geopolymerization alkali activator play an important role. Highest dissolution rate of Si⁺⁴ and Al⁺³ is reported as 10 M NaOH.

(a) Geopolymer precursor. (b) Geopolymer backbone.

Geopolymer membrane

Geopolymer membrane play significant role in the effectiveness and sustainability of wastewater treatment.

Improved performance Characteristics

Sustainability to the environment

As compared to conventional material, manufacturing of Geopolymer membrane are usually uses low energy and produces fewer carbon emissions. This is consistent with the circular economy’s tenets, which call for recycling waste materials into useful goods.

Porosity and filtration efficiency

Heavy metals and organic pollutants may be effectively filtered out thanks to the porous nature of Geopolymers. Their filtering capacities can be further enhanced by making changes to increase porosity.

Mechanical and chemical stability

The exceptional mechanical strength and chemical resistance of geopolymer membranes are essential for withstanding the severe conditions frequently present in wastewater treatment settings.

Role of GPM in wastewater treatment

Heavy metal removal

Heavy metals from wastewater may be effectively adsorbed by geopolymer membranes, resolving serious environmental issues associated with industrial contamination. They can be used to cleanse polluted water sources because of their capacity to bind metal ions selectively.

Membrane bioreactors

Advanced membrane-based bioreactors are the result of innovations like adding photocatalysts to geopolymer membranes. These systems improve overall treatment efficacy by filtering and degrading contaminants.

Filtration technologies

Numerous filtration technologies, such as microfiltration and ultrafiltration systems, can used geopolymer. Because of their versatility, wastewater treatment technologies can be connected with existing infrastructure, increasing their versatility.

Impact of Pore size of GPM

The effectiveness of geopolymer membranes to filter out impurities is directly impacted by their porosity. Greater permeability, made possible by higher porosity, permits water to flow through while holding onto larger contaminants and suspended particulates. This feature improves the membrane’s ability to remove impurities from water, which is crucial for efficient wastewater treatment.

Adsorption capacity

If membrane is porous it will provide more surface area for absorbing heavy metals and pollutants from wastewater. Researchers reported that porous GPM can meaningfully improve adsorption of different ions like ammonium ion, copper, nickel cadmium etc. due of this characteristic, geopolymer membranes work especially well in applications where harmful complexes need to be removed.

Anti-fouling properties

Geopolymer membrane design and modification may be helpful in reducing fouling, a common issue in membrane technology that eventually results in decreased performance. Researchers can develop membranes that prevent contaminants from building up on their surfaces and maintain greater operational efficiency by maximizing pore size and distribution.

Manufacturing techniques

Gel-casting technique

This technique combines surfactants with a foaming ingredient, like hydrogen peroxide. By maximizing the slurry conditions, the gelcasting technique enables the controlled creation of high-porosity geopolymer foams with pore size ranging from 67% to 86%. In addition to increasing porosity, this method customizes the membranes’ mechanical characteristics, which qualifies them for use in wastewater treatment applications.

Pore-forming technique

This method involves adding chemical foaming agents immediately to the geopolymer mixture. During the curing process, the foaming agents produce gas, which causes pores in the geopolymer matrix. This process has the benefit of creating ultra-macroporous structures, which can greatly enhance wastewater pollutants’ filtration and adsorption capabilities.

Composite forming method

The mechanical strength and porosity of geopolymer membranes can be improved by adding composite materials and pore-forming agents. Producers can attain desired properties suited for particular wastewater treatment requirements by mixing geopolymer matrices with different additives. This entails strengthening adsorption capabilities for heavy metals and organic contaminants as well as resistance to fouling.

Hydrothermal synthesis

This method creates geopolymer materials with increased porosity and surface area by applying high pressure and high temperature. Hydrothermal techniques are useful for adsorption procedures in wastewater treatment because they can create intricate three-dimensional pore networks that enhance mass transfer characteristics.

From Above discussion it is clear that fundamental factor in GPM manufacturing is to maintain the porosity. Porosity enhance efficiency of filtration, adsorption, mechanical stability etc. Researchers are enhancing further these techniques to treat contaminated water sources.

Schematic diagram of geopolymer preparation

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Modern Analysis Tools in Analytical Chemistry

admin — Wed, 14 Feb 2024 15:00:55 +0000

Modern Analysis Tools in Analytical Chemistry. Modern analytical chemistry is constantly evolving with advancements that stretch the limits of detection, accuracy, and speed. As the complexity of analytical challenges increases, state-of-the-art tools are essential for scientists to explore, quantify, and understand the myriad substances that they encounter in their research be they novel pharmaceuticals, environmental samples, or the frontiers of materials science.

Author: Hajira Mahmood

Today’s analytical chemist is equipped with an arsenal of sophisticated instruments and methodologies that enable precise qualitative and quantitative assessments. These tools span a wide range of techniques, each with its unique strengths and applications. Unraveling the potential and functionality of these techniques is key to pushing the boundaries of what can be measured and known.

Spectroscopy Techniques: UV-Vis, IR, NMR, Mass Spectrometry

Each spectroscopy technique in analytical chemistry unveils different facets of molecular identity and structure. Ultraviolet-visible (UV-Vis) spectroscopy provides valuable insights into the electronic structure of molecules, closely tied to their absorbance characteristics. Meanwhile, infrared (IR) spectroscopy is a powerhouse for identifying functional groups within compounds, tracing vibrations of molecular bonds.

Nuclear Magnetic Resonance (NMR) spectroscopy takes it a step further by offering detailed molecular topographies, allowing chemists to traverse the complex landscape of molecular architecture. Lastly, mass spectrometry (MS) stands out as a detective, identifying molecules by their mass-to-charge ratio with an unparalleled level of finesse, even capable of elucidating molecular weights and compositions of entirely unknown substances.

UV-Vis Spectroscopy

Primarily used for studying the absorbance of light and its interaction with matter. Key for understanding the electronic transitions in molecules.

Infrared (IR) Spectroscopy

IR identifies molecular vibrations, providing a fingerprint for functional groups within complex structures, essential in organic and inorganic chemistry.

NMR & Mass Spectrometry

NMR reveals molecular frameworks with high precision, while mass spectrometry allows the identification and structural elucidation of components in a mixture.

Chromatography Techniques: HPLC, GC, TLC

The application diversity within chromatography is immense. High-Performance Liquid Chromatography (HPLC) is a vital workhorse in pharmaceuticals due to its unmatched capability in separating complex mixtures. Gas Chromatography (GC) aptly separates volatile compounds, frequently deployed when analyzing environmental pollutants or forensic substances.

Thin Layer Chromatography (TLC) offers a quick and straightforward means of separating components, valuable for on-the-spot analysis or as a preparatory step for more refined techniques. These methods give chemists the power to peek into a compound’s intricate composition, unraveling the hidden layers of chemical interactions and purities.

High-Performance Liquid Chromatography (HPLC)

Essential for resolving complex biological and synthetic mixtures; optimized for speed, resolution, and quantification.

Gas Chromatography (GC)

Best suited for volatile substances; extensively employed in toxicology, environmental analysis, and quality control.

Thin Layer Chromatography (TLC)

An accessible, screening tool that’s instrumental in educational settings and as a preliminary analysis method in research.

Electrochemical Techniques: Voltammetry, Potentiometry

Voltammetry and potentiometry form the bedrock of electrochemical analysis, each exploring the redox behavior of substances through different lenses. Voltammetry records current as potential varies, unmasking the dynamic redox processes. By alternatively holding the voltage constant, potentiometry measures the potential, providing a direct gauge of species concentration.

Employed in settings ranging from environmental sensing to the research of electroactive compounds, these techniques are crucial for their sensitivity and selectivity in detecting trace elements and molecules.

Voltammetry

Explores electron transfer kinetics in redox. Often used in the examination of medical sensors and battery technologies.

Potentiometry

Great for measuring ion concentrations. Commonly involved in pH sensing and the food industry for quality control.

Thermal Analysis Techniques: DSC, TGA, TMA

Thermal analysis unveils material properties under the influence of temperature changes. Differential Scanning Calorimetry (DSC) is profoundly insightful for studying phase transitions and estimating thermal stability, making it indispensable in polymer science and pharmaceuticals. Thermogravimetric Analysis (TGA) tracks weight changes to decipher decomposition patterns, pivotal for compositional analysis.

Thermomechanical Analysis (TMA) measures the dimensional response of materials, crucial for understanding expansion properties and mechanical behaviors. Each of these techniques guides materials scientists, chemists, and engineers in constructing heat profiles essential for material design and evaluation.

Differential Scanning Calorimetry

Thermogravimetric Analysis

Monitors change in material weight under controlled temperature, an excellent tool for the study of thermal stability and composition.

Thermomechanical Analysis

Measures physical changes in dimensions, offering insights into mechanical properties related to temperature variations.

Microscopy Techniques: SEM, TEM, AFM

Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Atomic Force Microscopy (AFM) serve as gateways to the nanoworld. SEM paints a detailed landscape of surface topography, while TEM penetrates deeper, imaging the innermost structure of sample material. AFM, on the other hand, stands unique by feeling the surface at the atomic level, making visible the invisible forces that define molecular interactions and surface properties.

Transcending mere magnification, these microscopy methods are indispensable tools for material scientists, biologists, and nanotechnologists in their quest to visualize and understand substances at the most intricate level.

Scanning Electron Microscopy (SEM)

Provides topographical contrast and material composition at nanoscale resolution, exemplifying surface analysis.

Transmission Electron Microscopy (TEM)

Gives access to the inner structure of materials at the atomic level, essential for detailed structural analysis.

Atomic Force Microscopy (AFM)

Enables the mapping of surfaces down to the atomic scale by detecting interatomic forces, vital for molecular and materials research.

Data Analysis and Interpretation Methods

In analytical chemistry, the deluge of data from various sophisticated instruments necessitates robust analysis and interpretation methods. Whether it’s multivariate statistics in spectroscopy, chemometrics in chromatography, or image analysis in microscopy, these methods transform raw data into meaningful insights.

Machines and algorithms are engaged to discern patterns, correlate structures with properties, and predict behaviors, turning vast datasets into actionable knowledge. This section of analytical chemistry is as much about creativity and critical thinking as it is about numbers and figures.

Statistical Models

Critical for discerning significance in data, statistical models underpin hypothesis testing and experimental validation.

Chemometrics

Utilizes mathematical and statistical techniques to extract valuable information from chemical data, enhancing instrument performance.

Converts microscopic images into quantitative data, allowing for in-depth characterization and measurement at micro and nano scales.

Conclusion and Future Prospects

The panorama of analytical chemistry is driven by relentless innovation and cross-disciplinary integration. With enhanced precision, chemists are forging a pathway to breakthroughs in medicine, environmental protection, and material development. The future beckons with tantalizing prospects such as real-time diagnostics, nano-scale synthesis, and the artificial intelligence-led analysis that will deepen our grasp of the chemical foundations of the world.

As we continue to advance, the central role of analysis tools in chemistry becomes ever more apparent, not just in expanding our understanding but in enabling solutions to global challenges. The edifice of analytical chemistry stands robust, ready to meet the unknown with sharp instruments and sharper minds.

UV-Vis and IR Spectroscopy	Expanding role in environmental monitoring
Mass Spectrometry	Advancements in speed and sensitivity
Chromatography	Developments towards microfluidics and on-chip technologies
Microscopy	Progressing towards higher resolution and real-time analysis
Data Science	Fusion of AI and big data in predictive modeling

Also read: Reticular Chemistry: A Story of Tiny Components and Endless Opportunities

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Analytical Chemistry as an Emerging Field: Scope, Analysis, Measurement, Current Challenges, Applications & Future Perspective

admin — Sat, 30 Dec 2023 06:41:57 +0000

Analytical Chemistry as an Emerging Field: Scope, Analysis, Measurement, Current Challenges, Applications & Future Perspective

Analytical chemistry as an Emerging Field: The science of gathering, analyzing, and disseminating data regarding the make-up and structure of matter is known as analytical chemistry. Stated differently, it is the science and art of identifying matter and its quantity. One common definition of analytical chemistry is the branch of chemistry that is in charge of:

1. Characterizing the qualitative and quantitative composition of matter.

2. Enhancing time-tested analytical techniques.

3. Applying current analytical techniques to novel sample kinds.

4. Creating fresh analytical techniques to quantify chemical phenomena

Author: Hajira Mahmood

Scope of analytical chemistry

Through the use of tools to detect potential chemicals and quantify those substances precisely, research aims to develop ever-better methods for assessing the chemical composition of natural and manufactured materials.

Through the use of tools to detect potential chemicals and quantify those substances precisely, research aims to develop ever-better methods for assessing the chemical composition of natural and manufactured materials.
Analytical chemistry is the study of substance to ascertain the amount and composition of each type of matter present.
Toxic chemical traces are found in the air and water by analytical chemists.
The method or process of its quantitative analysis may be based on the identification of a component in the qualitative analysis.
In qualitative analysis, the reaction might not be complete, but in quantitative analysis, the reaction need to be complete and provide distinct and identifiable products.

Current challenges in analytical chemistry

These days, developing and validating novel materials, techniques, and protocols to satisfy the expanding demand for quick, sensitive, selective, and environmentally friendly approaches is one of the biggest difficulties facing analytical chemistry, particularly quantitative analysis.

Qualitative analysis

This method determines the elements, ions, or compounds that are present in a sample and provides information about the substances that are there.

Quantitative analysis

This method deals with estimating the quantity of one or more components is present (indicates the quantity of compounds in a sample). Three categories apply to this analysis:

Volumetric analysis: also known as titrmetric analysis, measures the volume of a solution that has enough reagent in it for the analyte to completely react.
Gravimetric analysis: Using gravimetric techniques, ascertain the mass of the analyte or a chemically linked component.
Instrumental analysis: These techniques are predicated on the use of specialized instruments to measure a substance’s physical or chemical properties. These characteristics are connected to the quantity or concentrations of the component parts in the sample. These techniques are either directly or indirectly contrasted with common standard techniques. These techniques include:
Spectroscopic techniques: these involve measuring the interaction between electromagnetic radiation and analyte atoms or molecules, or measuring the radiation produced by analytes (visible, infrared, or ultraviolet); fluorimetry; atomic spectroscopy (absorption, emission); mass spectrometry; nuclear magnetic resonance spectrometry (NMR); and X-ray spectroscopy (absorption, fluorescence).
Electroanalytical methods: these entail measuring the desired electrical properties, such as electrical potential, current, resistance, temperature analysis, electrodeposition, voltametry, pH measurements, and amount of electrical charge.
Separation methods: In solid, liquid, and gas examples, they refer to the process of isolating one or more components from a mixture of components. Since instruments and other equipment are employed in separation procedures, these methods are included in the category of instrumental methods. Precipitation is a component of these techniques. chromatographic techniques, solvent extraction, ion exchange, and volatilization.

Measurements in Chemical Analysis

Measurement Units: A measurement typically consists of a unit and a number that indicates how much of that unit there is. In honor of the Système International ‘Unités,’ these units are referred to as SI units. There are situations where it is better to represent measurements using a prefix instead of the exponential word.

Uncertainty in Measurement

Accuracy

The degree to which an experimental measurement or outcome approaches the actual or accepted value is known as accuracy. Although it can be used on a single measurement, this is more frequently applied to the mean value of many replicates, or repeated measurements. Precision: The degree of agreement between outcomes is known as precision.

There are two types of errors in analytical chemistry: random (indeterminate) and systematic (determinate). The result of a measurement less the mean that would be obtained from an endless number of repeatability-constrained measurements of the same measure is known as random error. There will inevitably be random errors. They are inevitable as there is always some degree of ambiguity in any physical measurement. Only the balance’s uncertainty on weight or the glass pipette’s uncertainty on volume can be obtained by the analyzer, even with the greatest of caution. An ineffective instrument or analyst, or a flaw in the analysis procedure, are the sources of systematic errors. A systematic error-prone technique will always produce a mean value that differs from the actual value. Sometimes, a systematic inaccuracy is defined and described using the term “bias.” When a systematic mistake is present and the computed uncertainty of the measured value is small enough to detect a discernible difference when a comparison of the measured value to Systematic error is the mean that would be obtained, less the true value of the measured, from an endless number of measurements of the same measured taken under repeatability conditions.

Precision

The random or unpredictable error in a measurement or outcome. It is sometimes referred to as variability and can be statistically expressed by the relative standard or standard deviation. When a collection of results agrees with one another, it’s referred to as precision. The typical way to represent precision is as the deviation of a set of results from the set’s arithmetic mean. It is accurately taught to analytical chemistry students that high precision does not equate to high accuracy. It seems logical to assume differently, though. It can be better represented in terms of repeatability and reproducibility. The degree of agreement between the outcomes of multiple measurements of the same measure taken under the same measurement conditions is known as repeatability (of measurement findings). The degree of agreement between the results of measurements of the same measure made under various measuring settings is known as reproducibility (of measurement results).

Concentration

It is a general measuring unit that expresses how much solute is present in a given volume of solution or, alternatively, as the ratio of solute to solution volume. Although we typically think of the terms “solute” and “solution” in relation to liquid samples, they can also be used to refer to gas-phase and solid-phase samples.

Major areas of analytical chemistry

Analytical chemistry has four main subfields that are significant for their applications to many scientific fields. These fields include chromatography, potentiometry, acid-base techniques, and spectroscopy. Quantitative and qualitative problem solving is the focus of analytical chemistry.

Chemical substances can be studied quantitatively as well as qualitatively using spectrometry. They can be employed as a tool to assist in the classification of chemical structures, to identify the elements and isotopes present in a sample, and to calculate molecular weights. This can determine the molar mass and sample purity.

Gravimetric, volumetric, and titrimetric methods are examples of classical analytical techniques; ultraviolet-visible (UV-Vis), infrared (IR), and near-infrared (NIR) spectrophotometry, fluorimetry, atomic spectroscopy (absorption/emission), and electroanalytical chromatography are examples of instrumental techniques.

Role in industry

The pharmaceutical sector heavily relies on analytical chemistry. It is employed to learn more about the stability, purity, and composition of drugs. This helps guarantee that a medication satisfies all required quality requirements and is safe for general consumption.

Real life applications of analytical chemistry

Many branches of science make use of analytical chemistry. It can be used to measure your blood cholesterol levels, identify an unidentified substance discovered at a crime scene, or clean the oil you put in your car.

Two main techniques in analytical chemistry

Wet chemistry, which analyzes samples using other standard chemicals, and instrument methods of chemical analysis, which analyzes chemical compounds using scientific instruments and equipment, are the two most popular analytical chemistry approaches.

Future of analytical chemistry

The study of analytical chemistry is essential to numerous fields, such as forensic science, food safety, pharmaceuticals, and environmental monitoring. It’s possible that new analytical methods will keep developing and being applied in these fields in the future, such as nanotechnology and biosensors.

The rapid progress in science and technology is causing analytical separation methods and detection systems to get smaller. Numerous applications, such as drug testing, environmental testing, and food and beverage analysis, are anticipated to see growth in this area. Approaches in analytical chemistry are moving in the direction of sustainability. Developments in analytical chemistry can be directly impacted by advances in materials science. Other areas of analytical chemistry that have experienced significant advancements are as follows:

Small-scale fluid dynamics
Using mass spectrometry
The transcriptomics of
Infrared and Raman vibrational spectroscopy

It’s possible that new analytical methods will keep developing and being applied in these fields in the future, such as nanotechnology and biosensors.

Also read: Comparison of Conventional Verses Green Synthesis of Nanoparticles

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An Overview on Analytical Techniques in Chemistry

admin — Thu, 30 Nov 2023 14:46:29 +0000

An Overview on Analytical Techniques in Chemistry

Diving into the intricate world of chemistry, an exploration of analytical techniques unfolds, offering a panoramic view of methodologies essential for unraveling the secrets held within chemical substances. Read An Overview on Analytical Techniques in chemistry laboratories for smooth analysis operations.

Author

Izaz Ul Islam

What Is a Quality Control Chemist?

A quality control chemist (QC chemist) is a specific type of laboratory chemist, whose primary duties are to measure and test lab materials and products according to industry-specific standard procedures. Jobs are typically in the pharmaceutical or manufacturing fields. As a QC chemist, you assure adherence to all federal regulations and safety procedures. In addition to performing rigorous quality assurance of samples, some QC chemists are responsible for calibrating and performing maintenance on lab equipment. Relevant qualifications for this career include a bachelor’s degree in chemistry, experience in a chemistry lab setting, and skills like attention to detail and the ability to multitask.

Duties and Responsibilities:

There are the following duties that have to be performed by the Qc chemist officer.

· Organize raw materials

· Test products before, during, and after production

· Coordinate waste management

· Follow all company and governmental safety procedures

· Clean, maintain and store testing tools and equipment

· Create thorough reports on tests and your findings

· Evaluate testing protocols and suggest improvements.

Need to understand Importance of Analytical Chemistry

· In today’s era, the analytical chemist has a significant role, and to carry that role appropriately, they need to have the required skills and stick to an ethical code of conduct.

· Analytical research and development work in laboratories

· Drug formulation and development

· Chemical or forensic analysis

· Process and product development

· Product validation

· Quality control

· Toxicology

· Verify compliance with regulatory requirement

Work in marketing and law

· Teaching

· Food and Agriculture

· Oil and Petroleum

· Design instruments used in analytical analysis.

Important Questions you may ask during the Interview.

this section is a further extension of the topic, An Overview on Analytical Techniques in Chemistry.

Firstly, we have clarity in minds that why we selected analytical chemistry to study in this era of advanced sciences. Let go to sections that are important to understand chemistry.

1.U.V Visible:

Q. Basic Principle of U.V?

When matter absorbs ultraviolet radiation, the electrons present in it undergo excitation. This causes them to jump from a ground state (an energy state with a relatively small amount of energy associated with it) to an excited state (an energy state with a relatively large amount of energy associated with it). It is important to note that the difference in the energies of the ground state and the excited state of the electron is always equal to the amount of ultraviolet radiation or visible radiation absorbed by it.

Q Ranges of U.V and Visible?

200-400 U.V

400-800 Visible Below

200 vacuum region

Q. Calibration of U.V.?

The most commonly used solution for checking absorbance accuracy is potassium dichromate. Method tests absorbance at four wavelengths – 235, 257, 313 and 350 nm using between 57.0 and 63.0 mg of potassium dichromate in 0.005 M sulphuric acid diluted to 1000 mL. Since 2005 a second solution has been added to provide an additional test point at 430 nm. This uses the same amount of potassium dichromate but is made up to 100 mL (i.e. it is ten times more concentrated than the original solution). In both cases the A 1%/1 cm value is recorded and checked against the target range.

Wavelength accuracy is normally assessed by using either a sample containing a series of very sharp peaks such as a solution of holmium perchlorate or a holmium oxide and/or didymium doped glass filter or by measuring the emission from a lamp. If the instrument is equipped with a deuterium (D2) lamp as the UV source, this can be used. An external mercury (Hg) lamp can also be used. This is less convenient than using the previously mentioned methods but methodology exists (e.g. in the Ph. Eur. tests) for its use as an alternative to a glass or liquid standard. The advantage of emission lines is that they are inviolate (i.e. the emission wavelengths don’t change over time)

Q. On which principle U.V works?

It works on Lambets Beer Law

Q. Lamberts Beer Law?

As per the Beer-Lambert law, the greater the number of absorbing molecules (that have the ability to absorb light of a specific wavelength), the greater the extent of absorption of the radiation.

A=C ×L Q.

Transmittance and Absorbance?

Transmittance (T) is the fraction of incident light which is transmitted. In other words, it’s the amount of light that “successfully” passes through the substance and comes out the other side. Absorbance (A) is the flip-side of transmittance and states how much of the light the sample absorbed. It is also referred to as “optical density

Q. which Range of absorbance that follow lamberts Beer Law?

0—2 Absorbance

What kinds of detectors are used in UV-Visible spectroscopy?

A widely used detector in UV-Vis spectroscopy is the Photomultiplier tube. It consists of a photoemissive cathode (which is a cathode that releases electrons when it is hit by radiation photons), multiple dynodes (which is a device that emit multiple electrons for each striking electron), and an anode.

Light Sources

Hydrogen-Deuterium lamps are most widely used and suitable light source as they cover the whole UV region. Tungsten filament lamps are rich in red radiations used in visible Region.

2. FTIR:

Q. Basic Principle of FTIR.

FT-IR stands for Fourier Transform InfraRed, the preferred method of infrared spectroscopy. In infrared spectroscopy, IR radiation is passed through a sample. Some of the infrared radiation is absorbed by the sample and some of it is passed through (transmitted).A the result the molecules goes on vibrating of different types, as the wavelenth becomes longer the energy is not much enough to transist the radiations.

Q. What is Fourier transformer method?

The term Fourier-transform infrared spectroscopy originates from the fact that a Fourier transform (a mathematical process) is required to convert the raw data into the actual spectrum.

Q. Range of FTIR.

The commonly used region for infrared spectroscopy is 4000 ~ 400 cm-1. Near-infrared region (12800 ~ 4000 cm-1 ), mid-infrared region (4000 ~ 200 cm-1 ) and far-infrared region (50 ~ 1000 cm-1 )

Q. Solvents used in FTIR.

Commonly used solvents in IR solution cells are CCl4, CS2, and CHCl3; they are usually transparent in the important absorption region of the spectrum. Many organic compounds and polymers have poor solubility in IR solvents, such as CCl4, CS2

Q. Regions of FTIR.

The region between 400 cm-1 and 1500 cm-1 is known as the fingerprint region, so called because it’s difficult to assign all the absorption bands, and because of the unique patterns found there. Absorption bands in the 4000 to 1450 cm-1 region are usually due to stretching vibrations of diatomic units, and this is sometimes called the group frequency region.

3. HPLC:

Q. Basic Principle of HPLC.

The separation principle of HPLC is based on the distribution of the analyte (sample) between a mobile phase (eluent) and a stationary phase (packing material of the column). Depending on the chemical structure of the analyte, the molecules are retarded while passing the stationary phase.

Q. Types of Column used in HPLC.

Silica gel is the earliest chromatographic column packing used in liquid chromatography. It has a wide range of applications. However, it can only be used under the condition of pH 2.0-7.5.

C18 is the most commonly used non-polar reversed-phase column, and it has a wide range of applications. And the separation effect is good.

Cyano and Diol ion HPLC Columns.(Polar columns).

Q. Difference between C8 and C18 columns

C18 retain non polar compounds (Hydrophobic) while C8 has low hydrophobicity. As the carbon chains increases the polarity of columns will be reduced.

Q. normal and Reverse phase Chromatography and their Columns.

The main difference between normal phase and reverse phase chromatography is that normal phase chromatography has a very polar stationary phase and a non-polar mobile phase whereas reverse phase chromatography has a non-polar stationary phase and a polar mobile phase. Furthermore, the stationary phase of the normal phase chromatography is mainly pure silica, and the mobile phase is a non-aqueous solvent such as chloroform while the stationary phase of the reverse phase chromatography is a modified silica substrate with long hydrophobic long chains and the mobile phase is mainly water, methanol or acetonitrile.

Q. How HPLC gives quantitative and qualitative Analysis.

Peak area gives us quantitative and retention time determines qualitative

Retention time.

The retention time refers to the time which is required for a compound from the moment of injection until the moment of detection. Accordingly, it represents the time the analyte is in the mobile and stationary phase

Difference between HPLC & UHPLC.

The main difference is the size of used particles filled into the column. Particle sizes ≤ 2 µm are commonly used for UHPLC. Particles with a size of 3 µm up to 5 µm are usual for classical analytical HPLC

Q. What are hyphenated Techniques.

Combination of Chromatography and spectroscopy bring to hyphenated methods .e.g LCMS (HPLC-mass spectroscopy)

Components of HPLC.

The HPLC system mainly consists of an infusion pump, a sampler, a chromatographic column, a detector, and a data recording and processing device. Among them, the infusion pump, the chromatographic column, and the detector are key components. In addition, the gradient elution device, online degasser, auto sampler, pre-column or guard column, and column temperature controller can also be configured as required.

Types of Detectors in HPLC.

UV Visible detector

Refractive index detector

Evaporative light scattering detectors

Photodiode array Fluoresce Detector

Conductivity detectors

Q. Role of Equilibrium in separation?

Equilibration buffer is made to equilibrate the system (here it’s a column) with defined condition supposed to favor the first step in affinity chromatography which is to adsorb the molecule of interest onto the solid matrix.

Q. Types of Mobile phase?

Gradient: Polarity of Mobile phase is same during whole analysis

Isocratic: Polarity of Mobile phase is changes during analysis.

Things important for operation of HPLC.

· Degassing of mobile phase

· Proper dissolvation of sample.

· Column Washing

· Column saturation with Mobile phase before starting analysis.

· Fimilarization of nature of sample (to select column)

· Sample Filtration at micro levels.

· After analysis again washing of column.

Column washing and Care.

Start any wash procedure at the end of your day with the replacement of any buffer or modifier. In your case wash the column with 70% water; 15% methanol; 15% acetonitrile. Divert the column eluent to waste not to contaminate your detector(s). Wash the column slowly over to 100% methanol and wash for at least 15 minutes. Wash the column over to 100% acetonitrile and wash for at least 15 minutes. Depending on the type of column you are using you can store the column in 100% organic depending on the manufacturer’s recommendations. We store most of my C18 columns in 100% acetonitrile and the columns last for years.

4. Statistical Data Questions:

this section is an addition to the topic, An Overview on Analytical Techniques in Chemistry.

Accuracy:

Refers to how closely the measured value of a quantity corresponds to its “true” value.

Determinate errors:

These are mistakes, which are often referred to as “bias”. In theory, these could be eliminated by careful technique.

Error analysis:

Study of uncertainties in physical measurements.

Indeterminate errors:

These are errors caused by the need to make estimates in the last figure of a measurement, by noise present in instruments, etc. Such errors can be reduced, but never entirely eliminated.

Mean (m):

Defined mathematically as the sum of the values, divided by the number of measurements.

Median:

Is the central point in a data set. Half of all the values in a set will lie above the median, half will lie below the median. If the set contains an odd number of datum points, the median will be the central point of that set. If the set contains an even number of points, the median will be the average of the two central points. In populations where errors are evenly distributed about the mean, the mean and median will have the same value.

Precision:

Expresses the degree of reproducibility, or agreement between repeated measurements.

Range:

Is sometimes referred to as the spread and is simply the difference between the largest and the smallest values in a data set.

Random Error:

Error that varies from one measurement to another in an unpre- dictable manner in a set of measurements.

Sample:

A substance or portion of a substance about which analytical information is sought.

Sampling:

Operations involved in procuring a reasonable amount of material that is representative of the whole bulk specimen. This is usually the most challenging part of chemical analysis.

Sampling error:

Error due to sampling process(es).

Significant figures:

The minimum number of digits that one can use to represent a value without loss of accuracy. It is basically the number of digits that one is certain about.

Standard deviation (s):

This is one measure of how closely the individual results or measurements agree with each other. It is a statistically useful description of the scatter of the values determined in a series of runs.

Variance (s2):

This is simply the square of the standard deviation. It is another method of describing precision and is often referred to as the coefficient of variation.

5. Some General Questions:

this section is an addition to the topic, An Overview on Analytical Techniques in Chemistry.

Q. Explain What Is Buffer?

A buffer is an aqueous solution which has highly stable pH. It is a blend of a weak acid and its conjugate base or vice versa. On adding small amount of base or acid to buffer, its pH hardly change

Q. What Is Use Of Ion Pair Reagents?

The chemical substances that pair each other, to form complexes. These can use for stabilization of one of the molecule that is more active or to colorifying etc

Question 4. Explain What Is A Base Line?

Base line is nothing but the detectors response to the mobile phase

Q. What Is Use of Acetonitrile Compare to Methanol In Rp-hplc Method Development?

ACN is highly polar as compare to Methanol So provide Better resolution for many compound and it has property to form hydrogen bond so provide better selectivity.

Q. What Is Quality Control?

Quality control means to maintain the quality of product by calculating their content, different physical parameters, as per their specification IP/BP/USP/EP/JP.

Q. When We Get Moisture Content By Kf Higher Than By Lod, What Does This Indicate?

KF titration is the most accurate method in analyzing moisture content. But it is costlier and maintaince is too high. So in analysis of moisture content an alternative experiment is Loss on Drying (LOD), which gives approximate moisture value present in the given substance.

Explain The Term Aliquot And Diluent?

Aliquot: It is a measured sub-volume of original sample Diluent: Material with which sample is diluted.

What is difference between QC and QA

Although QA and QC are closely related concepts, and are both aspects of quality management, they are fundamentally different in their focus:

· QC is used to verify the quality of the output;

· QA is the process of managing for quality.

Q. What is LOD/LOQ

LOD: Minimum amount of analyte that can be detected.

LOQ: Minimum amount of analyte that can be quantified.

Difference between Distilled and Deionized water?

Distilled water is free of inorganic materials, suspended impurities, and most organic contaminants. To make or buy distilled water is expensive. While there may be school laboratory applications where distilled water is required, in many applications, deionized (aka demineralized) water will do just as well. Deionized water, like distilled water, is free of inorganic materials and most suspended contaminants. If you need organic-free water, buy a still or buy distilled water.

Q. Hardness of water:

The greater amount of Ca and Mg determines hardness of water.

What is Good Laboratory Practice (GLP)

Good Laboratory Practice contains a set of principles that provides a framework within which laboratory studies (Activities) are planned, performed, monitored, recorded, reported and archived. GLP help assure regulatory authorities that the data submitted are a true reflection of the results obtained during the study and can therefore be confidence upon when marking risk/safety assessment. This is An Overview on Analytical Techniques in Chemistry.

What is Working & Reference Standard?

A reference standard is the traceable, raw material standard (usually in crystallized form) that we dissolve and volumetrically dilute to make our working standard. The working standard is what we use to “do our work.” and this information makes it traceable and is recorded in the preparation notebook.

A reference standard is prepared for use as the standard in an assay, identification, or purity test and should have a quality appropriate for its use.

Q. What is Assay test?

An assay is an investigative (analytic) procedure in laboratory medicine, mining, pharmacology, environmental biology and molecular biology for qualitatively assessing or quantitatively measuring the presence, amount, or functional activity of a target entity (the analyte).

2.6 .Pharmaceutical Qc Questions:

this section is a further extension for the topic, An Overview on Analytical Techniques in Chemistry.

Disintegration Test:

It is the time required for the Tablet / Capsule to break into particles

Friability Test:

Friability is defined as the percentage of weight loss of powder from the surface of the tablets due to mechanical action.

Types of Tablets:

Coated, Sugar coated, Film coated, Enteric coated, capsules, Chewable tablets

Dissolution test:

Dissolution tests are performed to establish drug (Active Pharmaceutical Ingredient) release characteristics of solid oral products, such as tablets and capsules. The rationale for conducting these tests is that for a product to be therapeutically effective, the drug must be released from the product and should generally be dissolved in the fluid of the gastrointestinal (GI) tract. Q’ is the amount of dissolved active ingredient specified in the monograph which is required to be released in the stated time. This is An Overview on Analytical Techniques in Chemistry.

Which tablets are used in Calibration of dissolution Apparatus?

Non disintegrating (Salicylic Acid) and disintegrating (Prednisone) tablets are used in the calibration of dissolution test apparatus.

What is Out of Specification?

Out of Specification (OOS) means the test result that falls outside the specifications or acceptance criteria which has been specified in the official monographs or the Blend

Inside Qc department:

In process, Raw material, Packing material, Stability and finished product specification.

What is Out of Trend?

Out of Trend (OOT) means the test result that is within the specification limit or acceptance criteria as mentioned in the Blend, in process, Raw material, Packing material, Stability and finished product specification but outside the trend of previously tested batches.

Difference between Humidity and Relative Humidity?

Humidity – Measure of amount of water vapor present in the atmosphere.

Relative humidity– Water vapors amount exists in air expressed as a percentage of the amount needed for saturation at the same temperature

Tablets Test:

Dt test, Friability test, Dissolution test, Weight variation, Physical Apperance, Assay test

All test are performed according United state Pharrmacopeia,British Pharmacopeia and all complies authorties.

Injectables Tests:

Bacterial growth tests, Ph test, Conductivity test, Assay test.

Suspensions Tests:

Color , Odor, Ph Viscosity, Particle size, Redespersbility

7. Lab Accreditations:

this section is an extension of the original topic, An Overview on Analytical Techniques in Chemistry

Pakistan National Accreditation accredited first laboratory in 2004. SO/IEC 17025 is a company level accreditation based on a standard published by the International Organization for Standardization (ISO) titled “General requirements for the competence of testing and calibration laboratories”.17025 is advanced level of 17025.It has 15 Management requirements and 10 Technical requirements.

Also read: Difference Between Research Paper & Review Paper

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