Analytical Chemistry

CAPECCE

Choosing a method

Acquiring the sample

Preparing the sample

Eliminating interferences

Calibration

Calculating the result

Evaluation of result

What are the 7 steps in Quantitative Analysis?

Reagent Grade

It is a type of chemical that conform to the minimum standards of purity and used whenevr possible in analytical work.

Primary-Standard Grade

It is a type of chemical that is used to standardize solutions.

SHALS

Stable

High purity

Absence of water

Large molar mass

Soluble in medium

What are the properties of a primary-standard grade?

Special Purpose Reagent Grade

It is a type of chemical that is used for specific instrument (e.g. LC-MS—grade)

Technical Grade Chemicals

It is a type of chemical that has no official standard for purity.

Practical Grade Chemicals

It is a type of chemical that is used for synthesis.

6 months

It is the maximum holding time for acid-preserved samples that will be subjected to determination of chemicals.

Sulfuric acid, nitric acid, and/or perchloric acid

In wet ashing, what are the strong acids and oxidizing agents used to break down and remove the organic matrix of the sample to leave the metals only.

3:1 mixture of HCl and HNO3

Aqua Regia is a combination of and in what ratio?

What is the difference between absolute and relative error?

What is the formula of standard deviation for (a) population and (b) sample?

Formula for relative standard deviation (RSD) and coefficient of variation?

N

What is the formula for uncertainty in (a) sum/difference, (b) product/quotient, and (c) exponential calculations

Instrument blank

It is a type of blank used to establish the baseline of the instrument. It is done by determining the signal without sample added.

Solvent Blank

It is a type of blank used to measure the signal of the solvent.

Method blank

It is a type of blank used to detect contamination from method.

Z-Test

It is a statistical test used when population standard deviation is known and when sample size is large.

T-Test

It is a statistical test used when population standard deviation is unknown and when sample size is small.

Formula for z and t-tests statistical value

Reject

When z/t > z/t (critical), do we accept or reject null hypothesis?

What is the formula for f value in f-test?

What is the formula for Q in Q Test for outlier?

Formula for Internal Calibration

Formula for Single-Point Standard Deviation

Formula for Multiple-Point Standard Deviation

Limit of Detection

It is the smallest concentration from zero that can be reported with a certain level of confidence.

Limit of Quantitation

It is the smallest concentration of a sample with a distinguishable response, and acceptable accuracy and precision.

LOD=3σ/m while LOQ=10σ/m

What is the formula for LOD and LOQ?

The equilibrium lies to the right

What does K>1 denote in chemical equilibrium?

Kp=Kc(RT)^n

What equation shows the relationship of Kp and Kc?

Products

When Q<K, the equilibrium favors ___.

Reactants

When Q>K, the equilibrium favors ___.

Lower

Based on Le Chatelier’s principle, when pressure increases, the equilibrium will shift towards ____ number of moles

Activity

It is the effective concentration of a substance in a system where it behaves like it is available to react.

Weak acid/base and its salt

A buffer solution is a combination of a _______ and _______.

Formula for Henderson-Hasselbalch equation

Ionic strength tells how much of ions are present while activity tells how much an ion behaves like it is ready to react.

What is the difference between ionic strength and activity?

Formula of ionic strength

Formula of Debye-Huckel Equation

Na-Yellow (New York)

K-Purple (HKP)

Rb-Pink (RuBini)

What are the color of flames of the ff: (a) Na, (b) K, and (c) Rb?

What is the shortcut formula for calculating the mass of analyte in titration?