Polarography is a branch of voltammetry which uses a working electrode ________ or _________.

Polarography is invented by a Czech chemist

an electrochemical method in which information about the analyte is obtained by current

Formula for % Moisture Content

➢ when a pair of electrode is placed in a sample solution, it shows the potential difference by the addition of the titrant or changing the concentration of the ions.

➢ also used for the quantitative analysis

➢ it has an endpoint determined by a change in potential of an electrode immerse in solution

➢ Iodine (Titrant) is generated electrochemically in the titration cell

➢ Water is quantified on the basis of the total charge passed, as measured by the current and time.

➢ It can be determined by measuring the quantity of electricity required to electrolyze the susbstance

➢ This does not need standard solution

All statements about coulometric kft are true except

1. This measures water level much lower than the volumetric method.

2. Detects the endpoint of the titration using the double platinum pin indicator electrode.

3. Sensitive because it can measure even the lowest or small portion of water.

which statement is/are true about volumetric kft

1. This measures water level much lower than the volumetric method.

2. Detects the endpoint of the titration using the double platinum pin indicator electrode.

3. Sensitive because it can measure even the lowest or small portion of water.

Volumetric KFT is also known as

➢ Also known as the DIRECT TITRATION (because the analyst approaches the endpoint directly).

➢ Dispenses the titrating reagent (containing iodine) into the cell, using the burette.

➢ Calculates the end result based on the volume of the KF reagent dispensed, using the on-board microprocessor.

Karl Fischer Titration (water %) formula

In Karl Fischer Titration (water %) formula, F means

In Karl Fischer Titration (water %) formula, V means

In Karl Fischer Titration (water %) formula, Wt means

➢ It deals with the study of the rotary power (optical rotation or specific rotation) of substances.

➢ Rotation of linearly polarized light as it travels through certain materials.

In polarimetry, only chiral can be used.

It is stereoisomers that differ in spatial arrangement of atoms. Asymmetric in such a way that the structure and the mirror image are not super imposable.

Chiral are ___________.

Achiral are ___________.

In polarimetry, common samples are

➢ Also known as the “OPTICAL ACTIVITY”

➢ It is the power of rotating plane polarized light when light

passed through solutions of organic substances.

when the direction of the rotation is toward the right [+] = CLOCKWISE (S-ENANTIOMER)

when the direction of the rotation is toward the left [-] = COUNTER CLOCKWISE (R-ENANTIOMER)

Common example is fructose

Common example is glucose

Importance of polarimetry includes

1) Assessment of the PURITY of a liquid compound, in comparison with a known / standard

2) Establish identity of substances (can identify if a substance is a dextro or a levo)

3) Establish purity and concentration of samples

4) Indication of its therapeutic value

Example: measures syrup

Clinical Application: can easily determine the sugar level in diabetic patients

• can be computed to manipulate the polarization

• If the ___________ of a sample did not meet the ones in the monograph, there is a possible presence of impurities

the conditions that involved the malformation of arms and legs of babies

root cause of phocomelia

Thalidomide occurs in two mirror images

contains sedative substance

teratogenic that has effect on the baby

a racemate that has an equal amount of left and right handed enantiomers

o used for nausea or morning sickness

o The separation between R and S enantiomer is ineffective and no use.

Which of the two is the formula for specific rotation that has a concentration of g/100ml

Which of the two is the formula for specific rotation that has a concentration of g/ml

In the formula of specific rotation, the image means

In the formula of specific rotation, a means

In the formula of specific rotation, l means

In the formula of specific rotation, c means

In specific rotation, units are actually cm2 g-1, but usually just given as degrees.

➢ It deals with the study and measurement of index of refraction of substances in order to assess their composition of purity

➢ commonly uses volatile oils as a sample

Principle of Refractometry

In the specific rotation of the substance determined at temperature of ________ using the D-line of sodium [wavelength of 589 n, it is the light source of all polarimetric measurements]

In the specific rotation of the substance determined at temperature of 25C using the D-line of sodium [wavelength of ________, it is the light source of all polarimetric measurements]

Reporting of Refractive Index

The N (Italicized) means

Reporting of Refractive Index

The D means

Reporting of Refractive Index

The 20 means

REFRACTIVE INDEX CHARACTERISTICS INCLUDES

Refractive index normally determined up to a

REFRACTIVE INDEX SIGNIFICANCE EXCEPT

An instrument that measured the extent to which the light is bent or refracted, when it moves from the air or vacuum into the sample

Most common refractometer and a bench top instrument that offers the highest precision.

An abbe refractometer that has the circulating water bath.

An abbe refractometer that has the circulating water bath and has the instant reading of n.

An abbe refractometer which wavelength is equal to 589 nm. Allows the measurement of n at different wavelength.

An abbe refractometer which circulating water bath is no longer required.

Refractometer part no. 1

Refractometer part no. 2

Refractometer part no. 3

Refractometer part no. 4

Refractometer part no. 5

Refractometer part no. 6

Refractometer part no. 7

Its function is to fix the place at the center of the cross or to adjust the reflection borderline at the center of the cross mark.

Its function is to adjust the sharpness.

It is where the volatile oil will be placed, and it is made of glass. When sample is placed it is required to use a plastic dropper or else it can create scratches in the glass.

Once the volatile oil is scattered, it is used as cover

The box part is known as ___________ which means that it is the concentration of sugar. It can be used in wine to determine the percent of sugar in grape wine. Uses refractometer to check degrees Bx.

THE FORMULA FOR ADJUSTING THE RAW REFRACTIVE INDEX VALUE IS:

The box part of the formula means that

In calculating the refractive index, the equation automatically adjusts the correction factor up or down from 20 ̊C.

The formula for pH is/are

The formula for pOH is/are

It is based on the reaction of water with an anhydrous solution of sulfur dioxide and iodine in the presence of a buffer that reacts with hydrogen ions.

The excess reagent is added to the test specimen, sufficient time is allowed for the reaction to reach completion, and the unconsumed reagent is titrated with a standard solution of water in a solvent.

The Iodine is not added in the form of a volumetric solution but is produced in an iodide-containing solution by usually anodic oxidation.

Oven drying is classified as:

Ca carbide method is classified as:

This method has specificity in determining the water content.

Azeotropic-toluene distillation is classified under:

This method is applied to most systems with a moisture content of >0.1%.

Clumping and surface crust formation will lead to erroneous results.

Pans should be dried in an oven and stored in a desiccator prior to use.

pH meter is used for measuring fluid concentrations such as the sugar content.

A refracting prism that contains illuminating prism.

A refracting prism that contains the measuring prism and acts as sample compartment.

An internal measurement scale is used to observe both the total reflection borderline and the instrument’s internal measurement.

A refracting prism that prevents stray light from entering the front of the measuring prism.

➢ It measures the mass of a sample, as it is heated, cooled, or held at constant temperature in a defined atmosphere.

➢ Limitation: do not distinguish weight loss due to vaporization of water from other volatile compounds.

The methods under thermogravimetric includes

The measurement is based on _______ reaction. _________ reaction occurs where the water is separated chemically from the remainder of the sample.

Advantages of chemical in moisture determination

Advantages of chemical in moisture determination except

• In moisture determination under chemical it is a method wherein rapid determination of water content from gas pressure uses calcium carbide.

• Usually used to determine the water content in the soil (calcium carbide +water) producing gas.

a mixture of two or more liquids (chemicals) in such a ratio that its composition cannot be change by simple distillation

In moisture determination under spectroscopic it includes

The most successful of water content determination in foods. Rapid, accurate, non destructive to the sample.

Instrument used for measuring the moisture content in the atmosphere.

The measurement of relatively low concentrations of water in vapor state in a gas. Water forms a fog or mist when suddenly cooled.

• reaction of water with anhydrous Sulfur dioxide and iodine

• you add a standard titrant to the analyte until you reached the endpoint

• Excess reagent is added to the test specimen, the unconsumed reagent is titrated with standard

solution of water in a solvent such as methanol.

• You add an excess of standard titrant to the analyte, and then you titrate the excess titrant to determine how much is in excess.

KF reaction is used, however, iodine is not added in the form of vol.sol. but is produced in an iodine- containing solution by usually anodic oxidation.

Infrared drying is faster and more reliable than conventional oven drying.

Moisture or water content determination is an important parameter in the following aspects of drug manufacture;

USP SPECIFICATION FOR MOISTURE CONTENT: CORNSTARCH AND WHEAT STARCH

USP SPECIFICATION FOR MOISTURE CONTENT: TAPIOCA STARCH

USP SPECIFICATION FOR MOISTURE CONTENT: POTATO STARCH

USP SPECIFICATION FOR MOISTURE CONTENT: ACACIA, USP

USP SPECIFICATION FOR MOISTURE CONTENT: LACTOSE, USP

USP SPECIFICATION FOR MOISTURE CONTENT: REFINED WHITE SUGAR

USP SPECIFICATION FOR MOISTURE CONTENT: TALC, USP

USP SPECIFICATION FOR MOISTURE CONTENT: METHYLCELLULOSE

In IR analyzer, the greater the surface area of material exposed to the environment, the faster the rate of moisture removal.

An type of pan in IR that is used because they are relatively cheap and have a high thermal conductivity.

What type of IR analyzer is available in CEU-Manila?

WARNING AND SAFETY IN USING IR ANALYZER