The modified limit test for sulfate is based on gravimetric analysis, where sulfate ions (SO₄²⁻) are precipitated as barium sulfate (BaSO₄) using barium chloride (BaCl₂). The precipitate is then collected, dried, and weighed to determine the sulfate concentration. Chemical Reaction: Ba2+(aq) + SO₄2−(aq) → BaSO₄(s) Procedure for Limit Test for Sulfate: Prepare Test Solution: Prepare … Read more
The modified limit test for chloride is based on the Volhard titration method, where chloride ions (Cl⁻) are precipitated with silver nitrate (AgNO₃) and the excess silver nitrate is titrated with ammonium thiocyanate (NH₄SCN). The process involves two key reactions: Chemical Reactions of Limit Test for Chloride: Precipitation of Chloride Ions: Ag + (aq) + … Read more
The limit test for heavy metals is a qualitative test that determines if the concentration of heavy metal ions (e.g., Pb²⁺, Cu²⁺, Cd²⁺) in a sample is below a predefined acceptable limit. The test is based on the reaction between heavy metal ions and sulfide ions (S²⁻) from sodium sulfide (Na₂S), forming colored metal sulfide … Read more
The limit test for lead is a qualitative test that determines whether the concentration of lead ions (Pb²⁺) in a sample is below a predefined limit. It is based on the colorimetric reaction between lead ions (Pb²⁺) and potassium chromate (K₂CrO₄), which forms a yellow-colored precipitate of lead chromate (PbCrO₄). Chemical Reaction: Pb2 + (aq) … Read more
The limit test for arsenic is a qualitative test used to determine if the concentration of arsenic in a sample is below a predefined limit. The test is based on the reduction of arsenic (As) to arsine gas (AsH₃), which reacts with silver nitrate to form a yellow to brown stain on filter paper. Chemical … Read more
The limit test for iron is a qualitative test that checks whether the iron ion (Fe³⁺) concentration in a sample is below a specified limit. It is based on a colorimetric reaction between iron ions (Fe³⁺) and potassium thiocyanate (KSCN), forming a red-colored complex. Chemical Reaction: Fe3+(aq) + 6SCN−(aq) → [Fe(SCN)6]3−(aq) Procedure of Limit test … Read more
The limit test for sulfate is a qualitative test that detects whether the sulfate ion (SO₄²⁻) concentration in a sample is below a predefined acceptable limit. It is based on the precipitation reaction between barium ions (Ba²⁺) and sulfate ions (SO₄²⁻), forming an insoluble white precipitate of barium sulfate (BaSO₄). Chemical Reaction: Ba2+(aq) + SO₄2−(aq) … Read more
The limit test for chloride is a qualitative test that detects whether the concentration of chloride ions (Cl⁻) in a sample is below a predefined acceptable limit. It is based on the principle of a precipitation reaction between silver ions (Ag⁺) and chloride ions (Cl⁻), resulting in the formation of an insoluble white precipitate of … Read more
A limit test is a type of analytical method used to determine whether a specific impurity or substance in a pharmaceutical product is present at a concentration below a predefined acceptable limit. Limit tests are typically employed when the impurity or substance is not expected to be present in significant amounts, or when the impurity … Read more
Impurities in pharmaceutical substances are unwanted chemicals or compounds in pharmaceutical substances that can affect the drug’s quality, safety, and efficacy. They are classified into organic, inorganic, or residual solvent impurities and can originate from various sources. Sources of Impurities in pharmaceutical substances 1) Starting Materials and Reagents: Impurities may arise from impure raw materials, … Read more
