Usage of Chemicals for Aromas

Different pigments and aroma chemicals are tested by and adjusted in the product by the QC chemist. All cleaning and hygiene products have these sort of "accessory" chemicals that provide the distinct scent or colour, such as green apple-scented and coloured detergent or coconut shampoo. It's also a vital selling point of the product. Compounds like aldehydes and benzene, which although are highly toxic and dangerous, provide a nice, sweet smell to products like detergents. Joe has to be careful when handling these chemicals, but he makes sure that there isn't too high of a concentration of these additives in the sample solution by using other methods such as titration HPLC, and colorimetry. Fatty aldehydes, which are long chains of carbon atoms that have a terminal aldehyde group are the types of aldehydes that are commonly used by QC chemists to adjust the fragrance of the product. Aromatic aldehydes such as benzaldehyde are also compounds that have a pleasant odour and used in Joe's industry. These compounds can be obtained from nature as raw materials, or they can be formed by oxidation of primary alcohols. However, Joe doesn't really perform the oxidation in the lab, as it takes time, and the quality/amount produced is not sufficient enough.

The structure of benzaldehyde.                                             Fatty aldehyde above.

The usage of aromatics and aldehydes' scents to adjust the fragrance in QC reminds me of our study of esters and the specific esters that have a distinct scent used for different purposes in different industries. This was discovered through the esterification lab, and now I have found a place (quality control chemistry!) where these concepts can be applied in the real world.

The structure of ethyl ethanoate is shown above, and it has a distinct "nail polish remover" scent.

Amlyase Test

Some enzymes are added to cleaning products like detergent in order to improve the washing performance and efficiency of the product. Two of the most common enzymes used in detergents that Joe utilizes are proteases and amylases, which are considered active ingredients, because they help break down stains faster and more easily. Amlyase is an enzyme that catalyzes the breakdown of starch into its monomers (this relates to not only catalysts and enzymes in biology, but also to polymer chemistry!). Ogliosaccharides, dextrins, and maltose, which are monomers of starch, are soluble, so it causes the stain to be physically cut off from the surface. Protease is similar to amylase, because it carries out hydrolysis in order to synthesize a large protein molecule by creating peptide bonds to join amino acids together. The proteins synthesized by protease are used to remove protein-based stains that are usually very difficult to get rid of.

Above is part of a starch molecule that can be broken down into maltose monomers by hydrolysis, catalyzed by the enzyme amylase.

Joe, the QC chemist, uses a variety of tests such as amylase test tablets to analyze the activity of amylase or other enzymes in the samples of cleaning products. The tablets are starch polymer chains that are interlinked to form spheres called bio-degradable starch microspheres (DSMs), which are insoluble in water. A water soluble blue dye is also added to the DSMs, but the whole thing still remains insoluble. The tablets are placed into the sample of the cleaning product being tested that has alpha-amylase in it, and the DSMs begin to be degraded by the enzyme. The blue dye will then be isolated from the DSM, and this is the key to measuring amylase activity levels. The dye can be measured in a spectrophotometer (it uses the measurement of reflection/transmission as a function of wavelength), and the concentration of the dye is proportional to amylase activity. Amylase levels must be in the right range to ensure that the product has enough active chemical in order to perform efficiently, but not too much to the point where the breakdown of starch is overpowering, causing other vital components of the detergent to be broken down as well. The use of enzyme as a catalyst and polymers/monomers is applied right here in quality control chemistry.

Here is a picture illustrating how DSM works. In this situation, DSM is used to stimulate blood clotting rather than indicate amylase activity levels. The blue dye is also evident in this picture.

Sodium Chloride & Soap Viscosity

When Joe is performing quality control tests on liquid soap, it is important for him to consider the viscosity of it because it is important for soap to have a certain thickness to it in order for the product to feel nice and comfortable on the consumer's hands. Joe increases the viscosity by adding sodium chloride --a table salt that I have come across many times in my career as a high school chemistry student. So how does it actually work?

First off, soap is prepared through saponification, since natural soaps are sodium or potassium salts of fatty acids. Saponification is the reaction that occurs between an ester and a strong base, such as sodium hydroxide or potassium hydroxide. When the reaction occurs, an alcohol and a salt of the acid is formed. The latter is the soap. For instance, when methyl methanoate reacts with sodium hydroxide, it forms methanol (the alcohol) and a sodium salt of ethanoic acid (the soap).

The saponification of methyl methanoate in the presence of sodium hydroxide (first line of the image)

Sodium chloride can be added to the soap in order to precipitate it, thus making it more viscous. This is related to the common-ion effect, which is responsible for the reduction in solubility of a compound when a soluble compound consisting of one of the ions in the other compound is added to the solution in equilibrium. Therefore, adding sodium chloride to soaps causes it to precipitate, increasing the thickness. Not only is this due to the common-ion effect, but it is also due to increased ionic strength. Since sodium chloride is considered an electrolyte, it can be decomposed into sodium and chloride ions. Therefore there is an increase in ionic strength due to the formation of ions that causes precipitation. The concept of electrolytes, ions, and precipitation which I have learned throughout high school chemistry have been adapted to the adjustment of viscosity in soap in the field of quality control.

How NaCl is an electrolyte since it decomposes into Na+ and Cl- ions.

Colorimeter

The colorimeter is another one of Joe's essential lab equipment. It is a device used in colorimetry to determine the concentration of a solute in a solution that has colour by measuring the absorbance of specific wavelengths of light by the solution. With this device and concept, the Beer-Lambert law is applied. This law states that the concentration of a solute is directly proportional to its absorbance or colour intensity. However, there are many other factors that may affect the above statement. For instance, how intensely a substance absorbs colours may depend on the chemical being used, and its arrangement of electrons and energy levels. Since the concentration of a solute is proportional to its absorbance, then as concentration increases, the spectrum shown has fewer colours. Also, not only does the concentration of the solute affect the results, but so does the thickness of the solution. The absorbance is also directly proportional to the thickness of the substance. So overall, more intensely coloured compounds possess a more intense hue than less concentrated compounds. This was evident in the dilution lab that I did last year, where a series of liquid compounds were prepared through dilution, and each compound had a different concentration, evident by the varying colour intensities.

The increasing intensity of hues (right to left) indicates increasing concentration.

Joe uses the colorimeter by first selecting the appropriate wavelength, depending on the sample, to be measured, and then continues to carry out operating the machine to receive an absorbance value from the meter, and then this value can be used to find the concentration of the solution with Beer's Law.

A typical colorimeter.

The Interview

Here it is! A copy of the interview, questions and answers, I conducted with Joe!

What does a quality control chemist do?

- quality control: testing samples of raw materials or products either in mid-stage or close to final stage to make sure that they are of high enough quality, reaching the standards and qualifications, before the product can be mass produced

- research and development of products

- perform various chemical methods and procedures in the lab

Specifically, what company do you work for, what is your official title/position, and what are your duties?

- lead chemist: works in the lab, chemical reactions, testing the products, analyzing, quality control of raw materials to match all the qualifications/standards, quality control of final product, whereas the chemical engineer does the processing and development of the product

- company: Javo-Mex (soap/detergent/bodywash/handsoap/cleaning products company; manufacture for P&G, Mr. Clean)

Could you describe your typical day at work?

- take samples of raw materials or the finished products to the lab for analysis

- follow different chemical methods to do analysis to make sure samples have reached qualifications

- if not reached qualifications, must tell the supervisors and stop production to find the problem

- Inspect other co-workers

- fill out a sample report (raw materials, final products have different reports)

- if the raw material/final product/mid-stage product is poor: give the report to another department

- once final product is approved, send to packaging department and then they will ship it out

- once raw materials are approved, send to processing/manufacturing department to make the product

What is your work environment like?

- in a company laboratory

- must always be sanitary

- sometimes if there were a problem, had to go to manufacturing department

- go to warehouse to sample the raw material

- get finished products from the production/manufacture line

Who do you work with directly?

- director of the quality control department

- chemists, chemical engineers, mechanical engineers, electrical engineers (if manufacturing has problems, they may consult me, or chemist consults them)

What are some of the challenges you face at work and how do you overcome them?

- understanding all the chemistry, following the manufacturing/production rules and standards

- when something is wrong with the raw materials:

- if sample is not good, call the raw material manufacturing company, and send back the materials

-when something is wrong with the final products:

- if sample is not good, keep hold of product and find out the problem by contacting the different departments

- solving the problem is hard; meeting with different departments to solve the problem

- tracing back to the processing stages of product

Around how many hours do you work per day, and how many days per week?

- during the "high season" (summertime; higher demand) : overtime --> 10 hours or more

- regular season: 8 hrs

- during "slow season" : 8 hrs

What is your favourite part about being a chemical engineer?

- the chemistry knowledge you get to apply

- the technology

What is your least favourite part about being a chemical engineer?

- exposure to toxic/poisonous materials (not healthy for the workers)

- boring routine, doing same thing over and over, monotonous

What are your skills and attributes that make you fit for this job?

- knowledge of chemistry

- chemistry or chemical engineering degree

- communication

- attention to detail

Can you go over the QC chemist-specific technology you use?

- different types of instruments: HPLC (high performance liquid chromatography), Infrared spectrum, viscometer (specifically rotational), colorimeter, pH meter

- use computer analysis with HPLC

What are some of the "chemicals and substances" that you utilize and what are they used for?

- sodium hydroxide --> adjust pH, hydrochloric acid --> adjust pH, sodium chloride --> adjust the viscosity (for hand soap), different kinds of pigments to adjust fragrance and colour, various strong acids and bases, propylene glycol and sodium xylene sulfonate to adjust viscosity, indicators

Could you give me an example of the methods you use in quality control?

- for detergent: check the colour, smell the odour

- check the pH is in the range using pH meter: specific ranges for specific products

- specific gravity is in the range

- check the viscosity with viscometer

- wet chemical method/titration used to check percentage of efficient chemical and concentrations

- micro confirmation test: make sure no bacteria in the product

Can inform me about your educational background and credentials, such as what undergraduate degree you graduated with, master's degree, professional degrees, etc.?

- master's degree in chemistry (specifically in polymer) at University of Detroit

- undergrad degree in organic chemistry in China

Which chemistry courses did you find the most important for your career?

- organic/inorganic chemistry

- analytical chemistry

- physical chemistry

What kind of a chemistry foundation do you need for this career?

- good understanding of organic chemistry, and inorganic chemistry, math/calculations

What specific topics in chemistry does a QC chemist need a good grasp on?

- chemical news, mostly inorganic and organic chemistry

What kind of training is needed before starting the job?

- the company trains me

- specific to the company; must follow the company's methods and tests and their qualifications/standards

- lab skills, and certain methods were required before one could take the job

- familiarize with safety procedures and health hazards during the job

- proper lab technique was perfected with more practice, and consistently doing job

What are some of the health hazards in your workplace, and what are the safety procedures you need to know?

- wear goggles, do reactions in the fume hood, wear gloves, lab coat, safely dispose of chemicals (biohazardous waste)

- benzene, sulphuric acid had to be handled with care

- Material safety data sheets had to read

What do you think is the future for Quality Control Chemists?

- job demand will be strong; because many manufacturing companies need them to "make sure everything is correct"

- demand for high quality/safe products always high

- or else products will not be the right quality and potentially dangerous to the public

- high standards for cleaning/hygiene products calls for more QC chemists

How do you think your field will advance as technology advances?

- using more highly technological instruments rather than traditional lab techniques

- more efficient, more accurate, faster

- have to learn more new technology (computers, instruments)

- will become large part of career

Would you be able to tell me what your annual salary is around?

- varies depending on many factors

- $50,000-100,000

In-Service Training

The company, Javo-Mex, trained Joe and its employees to perform the quality control tests, methods, and procedures properly. The training was very "company-specific", because the company sets the standards and qualifications for the raw materials and products. Most of the training was done prior to the job, and also many lab skills such as operating the machinery and traditional chemistry lab methods were required. Safety procedures and health hazards were also gone over before Joe started, and he continued to familiarize himself with them as he worked in the environment. Proper lab technique and handling of equipment and substances were perfected through practice and constant use everyday. Communication with not only fellow chemists, but the supervisor and people from different departments was a skill that was sharpened as Joe continued doing his job.

Career History

Unfortunately, this will be a rather short post. Here's some general information on Joe's path to his current career as a QC chemist. He started off by obtaining his undergraduate degree in chemistry in China, he became a school teacher for a while. Then he went to America to work on his master's degree. After graduating, he was hired by Javo-Mex as a quality control chemist, and he worked his way up to lead chemist, which is his current position.