Education in Analytical Chemistry

Chirality

Chirality is a term that describes the lack of mirror symmetry in an object. In other words, chiral objects cannot be superposed on their mirror images. For example, our feet are chiral, as the mirror image of the left foot, the right foot, cannot be superposed on the left foot.

Chiral objects exhibit a sense of handedness when they interact with another chiral object. For example, our left foot can only fit in the left shoe and not in the right shoe. Achiral objects — objects that have superposable mirror images — do not have a sense of handedness. For example, socks are achiral; as such, a sock can be worn on both feet equally well.

Chiral objects are identified by the lack of certain symmetry elements in their structure. Specifically, chiral objects lack a plane of symmetry: an imaginary plane that can divide an object into two equal halves. In addition, chiral objects also lack a center of symmetry: a point from which similar components of the object are equidistant and opposite to each other.

Chiral molecules exist as a pair of non-superposable mirror images. As a rule of thumb, molecules which have only one tetrahedral carbon atom with four different substituents attached to it are always chiral. Such a tetrahedral carbon atom is referred to as a chiral center. In general, to identify whether a molecule is chiral, the molecular geometry should be known. If the molecular geometry lacks a plane of symmetry as well as a center of symmetry, the molecule is chiral.

10 Tips to Jumpstart Your Job Search..

Whether you’re looking for your first professional position or a temporary job to build your bank account over the summer, searching for a job can be overwhelming. While it’s tempting to do nothing and hope a job falls in your lap, that is probably not your best course of action. There are many things you can do right now to increase the chances of finding that perfect position. If you’re just getting moving (or wondering where to begin), the suggestions here will help you jumpstart your job search and put you on the path to professional success.
1. Take one bite at a time

The only way to eat an elephant is one bite at a time. Make it a priority to spend one hour every day working on your job search. Go someplace where your friends can’t find you, turn your phone off (not just silent), and make real progress on your search. You don’t have to do everything today, but you do have to do some work to accomplish your goal.
2. Refresh your résumé

Your résumé is your single most important professional document. It is your marketing tool, where you present yourself to potential employers in the best possible light. In many cases, it is the first impression a potential employer has of you — but hopefully not the last one. You’ve probably been using the same résumé for a long time, updating it in bits and pieces as your situation changes. Now is the time to take a fresh, critical look at the overall picture.

Verify that everything is up-to-date and absolutely current. Are all of your most recent and most relevant skills included?
Look at the overall impression your résumé gives. Now is the time to remove some of your extracurricular activities from high school, especially ones that aren’t relevant to your career path.
Make sure your strongest selling points are up front, and quantify accomplishments where possible. You may need to reorganize the sections, update the headers, and re-write points about your experience to more accurately reflect your recent accomplishments. For example, instead of “Experience with HPLC,” say “Analyzed 25 samples per week using HPLC, including performing routine maintenance and upgrades to equipment”.
Create the best possible basic résumé, then customize it for each position. Your résumé will be one, or at most two, pages, so make every line count.

3. Update your LinkedIn profile

Take a critical look at your professional profile on LinkedIn. This is the first place most industrial employers go to look for candidates, so if you’re not there, you are invisible to most potential employers. If you don’t have an account yet, sign up (it’s free).

Be sure to:

Copy and paste content from your now-awesome résumé in to the appropriate sections of your LinkedIn profile.
Include a photo — a nice headshot with a plain background, taken by a friend (no selfies).
Include all the professional skills (and keywords) that are relevant to your current job search, and make sure they are consistent with what’s on your résumé. Don’t advertise only your analytical chemistry skills on LinkedIn, then send a résumé selling your organic chemistry knowledge. Employers like a coherent story.
Use your LinkedIn profile to go beyond what’s on your résumé. By participating in discussion groups and including links to your own blog and publications, you can expand the reach of your profile.

4. Perfect your intro speech

When you are interviewing for a position, it’s imperative to be prepared. Practice — out loud — your 2- or 3-sentence response to the questions, “Who are you?” and “What kind of a job are you looking for?” Describe not only what you are doing now, but where you want to go. For example, “My name is Alex James, and I am about to graduate from Big State University with a B.S. in chemistry. I especially enjoyed my undergraduate research project conducting HPLC analysis of over 50 steroid analogs, and I’m currently seeking an industrial position that will let me expand my skills in this area.” If you give people enough information so they know what you’re looking for, you can turn your entire network into job search agents (see next tip).
5. Organize your contacts list

Start a database, spreadsheet, text document, Google Doc, or whatever format works for you to track all your networking contacts and job leads.

Meticulously record:

Names of people you contact
Dates the contacts were made
Conversation topics
Information gleaned from the conversation
New job leads
Anything you might have promised to them, and the due date.

Once you have recorded this information, use these documents to follow up with all available leads. This can be especially helpful when your contact Victoria suggests you call her contact James. If you documented the conversation, you can contact Victoria afterwards and let her know how the conversation went and how much you appreciate the lead.

Create another document to track jobs you have applied for, or might want to apply for. Again, keep track of how you heard about the position, who you know at that company, when you applied, which version of your résumé you sent them, and so on. When you meet someone new, you can quickly tell if you’ve applied to their company, and, if so, for what position.
6. Update your references

Keep a references list of the names and contact information for three people who know you well and will speak well of you to potential employers. Make sure to touch base with them regularly. Updating them on your job search progress will force you to make progress, so you’ll have something to tell them. You should also decide if the people you selected are still best suited to talk about your professional skills.
7. Expand your contacts list

Possible sources of new contacts could include:

Current and former employers, teachers, co-workers
Current and former classmates
Speakers who presented on campus and audience members at their presentations
Fellow volunteers at science outreach activities
Friends from social clubs and other campus activities
Scientific recruiters

Think back through your professional history and identify people with whom you’ve lost touch. Use LinkedIn and other tools to reconnect — to rebuild your relationship, not just ask for a job! Ideally, you will have an in-person conversation, and even a short phone call is better than an email exchange, but whatever they have time for is better than nothing. You can ask for ideas for possible career paths, information about organizations, and especially for introductions to other people.

Recruiters and staffing agencies can be a good way for new graduates to get a first position because they use their professional network on your behalf; however, their primary focus is to fill the position, not to find you a job.
8. Research job listing sites

Using “chem” or “scient” will find many openings, often for jobs you’ve never heard of. Ignore the job titles and focus on the descriptions. Learn what skills employers are looking for and identify keywords to use in your résumé and in future searches.

Sites to start searching include:

C&EN Jobs
LinkUp
Indeed
LinkedIn

9. Browse company websites

Study the websites of companies in your local area that hire chemists. Read press releases about new areas of expansion and marketing literature about new products, and sign up for alerts about new information. Will they need people to support their new efforts? Do they sponsor lectures or outreach events where you might meet some of their employees?

You can also inquire about career fairs, where employers come on campus to interview students. The fair may be school-wide or focus on a specific department. If there are none at your school, check nearby schools and ask if you can attend their career fair.
10. Be where the chemists are

Put yourself anywhere that your fellow professional chemists will be. Seminars, student chapter meetings, ACS local section meetings… even science nights at local pubs, science museums, and science cafés can be great places to meet fellow scientists and learn about the job market.

If you’re going to volunteer, why not do it strategically? Find the student chapter or local section near you (webapps.acs.org/lslookup), and ask to help with any of their activities, such as science fairs, tutoring, or outreach events. Volunteering with your fellow professionals showcases your passion for science and your work ethic.

In summary, don’t panic just because you don’t have a position lined up. There are many things you can do to make yourself more visible and attractive to employers. The key is to start now, make a plan, and continue working every day until you reach your goal.
Bonus: Learn a new skill

It’s never too late to learn something new. Look at the skills required for the jobs you’re interested in, determine what you’re missing, and figure out how to get it. Suppose your dream job requires experience collaborating on dynamic teams. You could create a team of students to help each other study for final exams. Assign topics to individual members, arrange meeting times and locations, and find problem sets or sample tests for everyone to work on together. Not only will you be helping yourself, you will be able to add “Organized study team of 10 students” to your résumé!

Locally-Activated Chemo Drug Dodges Hair, Weight Loss..

Sarcoma is an aggressive form of cancer responsible for up to 20% of childhood cancers. Tumors often first appear in the extremities and the abdomen. Surgery is a primary treatment, but it is often combined with chemotherapy. In a recent issue of ACS Central Science, researchers propose a scheme to target chemotherapy medications specifically to sarcomas, leading to greater efficacy and fewer side effects.

Jose Mejia Oneto, Max Royzen, and colleagues developed a technology that shields a toxic and commonly used chemotherapeutic, doxorubicin, until it comes into contact with an activating agent held at the tumor site by a polymer material. While both the traditional delivery of doxorubicin and the new approach were successful in the initial treatment of sarcoma tumors in mice, only the site-activated drug kept the cancer from coming back. In addition to a better therapeutic outcome, the local activation strategy had fewer side effects. In particular, the researchers did not observe a decrease in new red blood cells, a marker of bone marrow suppression, which limits the tolerable dose in patients. Other unpleasant side effects, such as weight loss or changes in hair, were not observed compared with those treated conventionally. The authors intend to leverage the lower toxicity of their treatment to investigate whether shorter courses of their therapy using higher doses are even more effective, and expand this approach to other solid tumors and drugs.

The Culture and Chemistry of Tattoos..

What do Otzi the Iceman, Tofi women of New Guinea, and Kat Von D have in common? Believe it or not, the answer is tattoos! Tattooing has been a part of human history for thousands of years, and for a variety of reasons. Otzi, the 5300-year-old, health-riddled, mummified hunter discovered preserved in a glacier in the Ötztal Alps, has 61 tattoos located near his joints, suggesting they may have been associated with an ancient treatment for arthritis. Tofi women have swirl patterns on their faces, indicating their family lineage. And Kat Von D, a popular American tattoo artist and reality TV star, holds the Guinness World Record for most tattoos given to a single person in 24 hours: a whopping 400!

Whether an expression of religious beliefs, rites of passage, or personal interests, tattoos are here to stay. But have you ever really thought about the chemistry of tattoos? What exactly is in those inks, and how safe are they?
Getting ink into the skin

Permanent tattoos are made by injecting an ink into the skin using needles. When a tattoo needle punctures your skin, it causes a tiny wound. Your body responds to all wounds by sending macrophages to close the wound and swallow up any foreign invaders. In the case of tattoo ink, the pigment particles are too large for the macrophages to destroy, so they get stuck in the dermis.
A tattoo will fade if your immune system ever succeeds in breaking up the pigment particles. If you want to remove a tattoo, you can get a laser treatment to target a single color in your tattoo and break up the pigment particles into something the macrophages can handle.

What’s in tattoo inks?

Tattoo inks are solutions comprised of a carrier and a colorant. The carrier is the fluid that is used to transport the colorant to the application location. It may contain glycerin, water, isopropyl alcohol, and witch hazel.

Tattoo colorants are typically pigments — intensely colored compounds that can reflect light in the visible region of the light spectrum — as opposed to dyes, which require a physical or chemical interaction to be anchored into place. In other words, dyes must react with the surface of the skin to develop their color and stay in place. Conversely, pigments provide color without needing a chemical reaction, and are held in place by intermolecular or physical forces.

Historically, pigments used in tattoo inks derived from mineral or geological sources to produce certain colors and hues. For example, carbon (carbon black) and iron oxide were used to produce a black ink. Cinnabar, a mercury sulfide compound, was used to produce red hues. Cadmium compounds, such as “cadmium red (CdSe)” or “cadmium yellow (CdS or CdZnS),” were used to produce shades of red, orange, and yellow.

For the last 20 years, ink manufacturers have moved away from primarily mineral-based pigments to organic ones. Over 80% of the colorants used today are carbon-based, and approximately 60% of these organic pigments are azo pigments. About 30% of the pigments and dyes are approved for cosmetic use, while a number of others were originally developed for industrial applications, like paints or textiles.

Tattoo inks also include a number of additives, such as surfactants, binding agents, fillers, and preservatives. Many of these additives are employed to keep the pigments in a uniform suspension to avoid microorganism growth in the product after opening.
Potential risks

There are very real risks involved with inks and the tattoo process. The most common of these risks is that of an infection. Other known adverse reactions include allergic-hypersensitivity and auto-immune reactions, granulomas, and interferences with medical diagnoses and treatment.

Also concerning, there are more than 200 colorants and additives in current use to produce tattoo inks, but their long-term outcome in the body is not well understood. This is especially true for industrial pigments, which are not tested for cosmetic use. Azo pigments are known to release carcinogenic aromatic amines as they break down, specifically when exposed to solar and ultraviolet radiation.
Azo Compound

IUPAC defines azo compounds as derivatives of diazene (diimide), HN=NH, wherein both hydrogens are substituted with hydrocarbyl groups.

Government regulations for tattooing are varied and tend to be associated with location, licensing of the tattoo parlor, and consent for minors (see regulations by state). The primary risks monitored under these regulations are the possibility of infection and the transmission of disease through unsanitary procedures or conditions.

Long-term risks are associated with the quantity and type of pigment left in the skin producing the tattoo. An investigation by the Joint Research Centre (JRC) determined that inks may contain up to 60% by weight of the pigment component. But, what does that equate to under the skin? The research showed that, on average, a tattoo contains 2.53 mg of colorant per square centimeter, so a 400 cm2 (approximately 6"x10") will contain 1 gram of pigment. Thus, a little bit of pigment goes a long way, and not all pigments have potentially hazardous ingredients — which means the individual risk associated with a tattoo is highly variable.
Potential Degradation Pathways for Azo Pigments

Azo compounds may undergo reactions that cause the compound to cleave into a aromatic amines. Some degradation products, such as aniline, anisidine, and toluidine, have been identified as potential carcinogens.

For example, solvent Red 1 can cleave at the N=N bond:

Information is important to minimizing any risk. While there is no federal standard, distributors of quality inks now provide lists of ingredients used in their products as well as information about the conditions of use and other warnings. At a minimum, the packaging should reference the name and address of the manufacturer, an expiration date, conditions of use and warnings, batch identification, list of ingredients, and a guarantee of sterility. The ink should also be packaged for single use.

In spite of the risks, tattoos are a part of world culture and its long history. We humans seem to like to add a bit of color and self-expression to our bodies and surroundings. And, it seems the chemical industry is doing quite a bit of investigative research that will make tattooing even more intriguing in the future.

An illustration shows how laser light excites electrons (white spheres) in a solid material, creating vibrations in its lattice of atomic nuclei (black and blue spheres). SLAC’s LCLS X-ray laser reveals the ultrafast “dance” between electrons and vibrations that accounts for many important properties of materials.

At the Department of Energy’s SLAC National Accelerator Laboratory, scientists can study these coupled motions in unprecedented detail with the world’s most powerful X-ray laser, the Linac Coherent Light Source (LCLS). LCLS is a DOE Office of Science User Facility.

“It has been a long-standing goal to understand, initiate and control these unusual behaviors,” says LCLS Director Mike Dunne. “With LCLS we are now able to see what happens in these materials and to model complex electron-phonon interactions. This ability is central to the lab’s mission of developing new materials for next-generation electronics and energy solutions.”

LCLS works like an extraordinary strobe light: Its ultrabright X-rays take snapshots of materials with atomic resolution and capture motions as fast as a few femtoseconds, or millionths of a billionth of a second. For comparison, one femtosecond is to a second what seven minutes is to the age of the universe.

Two recent studies made use of these capabilities to study electron-phonon interactions in lead telluride, a material that excels at converting heat into electricity, and chromium, which at low temperatures has peculiar properties similar to those of high-temperature superconductors.
Turning Heat into Electricity and Vice Versa

Lead telluride, a compound of the chemical elements lead and tellurium, is of interest because it is a good thermoelectric: It generates an electrical voltage when two opposite sides of the material have different temperatures.

“This property is used to power NASA space missions like the Mars rover Curiosity and to convert waste heat into electricity in high-end cars,” says Mariano Trigo, a staff scientist at the Stanford PULSE Institute and the Stanford Institute for Materials and Energy Sciences (SIMES), both joint institutes of Stanford University and SLAC. “The effect also works in the opposite direction: An electrical voltage applied across the material creates a temperature difference, which can be exploited in thermoelectric cooling devices.”

Mason Jiang, a recent graduate student at Stanford, PULSE and SIMES, says, “Lead telluride is exceptionally good at this. It has two important qualities: It’s a bad thermal conductor, so it keeps heat from flowing from one side to the other, and it’s also a good electrical conductor, so it can turn the temperature difference into an electric current. The coupling between lattice vibrations, caused by heat, and electron motions is therefore very important in this system. With our study at LCLS, we wanted to understand what’s naturally going on in this material.”

In their experiment, the researchers excited electrons in a lead telluride sample with a brief pulse of infrared laser light, and then used LCLS’s X-rays to determine how this burst of energy stimulated lattice vibrations.

“Lead telluride sits at the precipice of a coupled electronic and structural transformation,” says principal investigator David Reis from PULSE, SIMES and Stanford. “It has a tendency to distort without fully transforming – an instability that is thought to play an important role in its thermoelectric behavior. With our method we can study the forces involved and literally watch them change in response to the infrared laser pulse.”

The scientists found that the light pulse excites particular electronic states that are responsible for this instability through electron-phonon coupling. The excited electrons stabilize the material by weakening certain long-range forces that werepreviously associated with the material’s low thermal conductivity.

“The light pulse actually walks the material back from the brink of instability, making it a worse thermoelectric,” Reis says. “This implies that the reverse is also true – that stronger long-range forces lead to better thermoelectric behavior.”

The researchers hope their results, published July 22 in Nature Communications, will help them find other thermoelectric materials that are more abundant and less toxic than lead telluride.
Controlling Materials by Stimulating Charged Waves

The second study looked at charge density waves – alternating areas of high and low electron density across the nuclear lattice – that occur in materials that abruptly change their behavior at a certain threshold. This includes transitions from insulator to conductor, normal conductor to superconductor, and from one magnetic state to another.

These waves don’t actually travel through the material; they are stationary, like icy waves near the shoreline of a frozen lake.

“Charge density waves have been observed in a number of interesting materials, and establishing their connection to material properties is a very hot research topic,” says Andrej Singer, a postdoctoral fellow in Oleg Shpyrko’s lab at the University of California, San Diego. “We’ve now shown that there is a way to enhance charge density waves in crystals of chromium using laser light, and this method could potentially also be used to tweak the properties of other materials.”

This could mean, for example, that scientists might be able to switch a material from a normal conductor to a superconductor with a single flash of light. Singer and his colleagues reported their results on July 25 in Physical Review Letters.

The research team used the chemical element chromium as a simple model system to study charge density waves, which form when the crystal is cooled to about minus 280 degrees Fahrenheit. They stimulated the chilled crystal with pulses of optical laser light and then used LCLS X-ray pulses to observe how this stimulation changed the amplitude, or height, of the charge density waves.

“We found that the amplitude increased by up to 30 percent immediately after the laser pulse,” Singer says. “The amplitude then oscillated, becoming smaller and larger over a period of 450 femtoseconds, and it kept going when we kept hitting the sample with laser pulses. LCLS provides unique opportunities to study such process because it allows us to take ultrafast movies of the related structural changes in the lattice.”

Based on their results, the researchers suggested a mechanism for the amplitude enhancement: The light pulse interrupts the electron-phonon interactions in the material, causing the lattice to vibrate. Shortly after the pulse, these interactions form again, which boosts the amplitude of the vibrations, like a pendulum that swings farther out when it receives an extra push.
A Bright Future for Studies of the Electron-Phonon Dance

Studies like these have a high priority in solid-state physics and materials science because they could pave the way for new materials and provide new ways to control material properties.

With its 120 ultrabright X-ray pulses per second, LCLS reveals the electron-phonon dance with unprecedented detail. More breakthroughs in the field are on the horizon with LCLS-II – a next-generation X-ray laser under construction at SLAC that will fire up to a million X-ray flashes per second and will be 10,000 times brighter than LCLS.

Related Article: Research Begins at SLAC’s Newest X-ray Laser Experimental Station

“LCLS-II will drastically increase our chances of capturing these processes,” Dunne says. “Since it will also reveal subtle electron-phonon signals with much higher resolution, we’ll be able to study these interactions in much greater detail than we can now.”

Other research institutions involved in the studies were University College Cork, Ireland; Imperial College London, UK; Duke University; Oak Ridge National Laboratory; RIKEN Spring-8 Center, Japan; University of Tokyo, Japan; University of Michigan; and University of Kiel, Germany. Funding sources included DOE Office of Science; Science Foundation Ireland; Volkswagen Foundation, Germany; and Federal Ministry of Education and Research, Germany. Preliminary X-ray studies on lead telluride were performed at SLAC’s Stanford Synchrotron Radiation Lightsource (SSRL), a DOE Office of Science User Facility, and at the Spring-8 Angstrom Compact Free-electron Laser (SACLA), Japan.

Neutron crystallography is an important complementary technique to X-ray crystallography since it provides details of the hydrogen atom and proton positions in biological molecules. Furthermore, as neutrons are a non-destructive probe, the resulting structures are free from radiation damage even at room temperature. Knowledge of H-bonding networks, water molecule orientations and protonation states, along with details of hydrophobic and electrostatic interactions, can prove vital towards a better understanding of many biological processes, such as enzyme mechanisms and can help guide structure-based drug design. Neutron crystallography aids in drug design. Credit: M. P. Blakeley

CHALCANTHITE

Beautiful blue chalcanthite crystals are composed of copper, sulfur, other elements, and water. Since this mineral contains water, it is very water soluble and can be absorbed in large quantities by any plant, animal or human — weakening and then killing it by shutting down essential body processes.

Chalcanthite is one mineral that can be easily made in the lab or with a home chemistry set, but it should never be tasted to test for salt content because an extremely serious overdose of copper could occur. Releasing small amounts of the blue mineral has killed entire ponds of algae and can have terrible environmental effects.

Don't Touch!
Torbernite..
Torbernite is a vivid green, prism-shaped crystal formed as secondary deposits in granite rocks, and is composed partially of uranium. Torbernite forms though a reaction between phosphorus, copper, water, and uranium.

Because it is so beautiful, many mineral collectors have taken a sample for their collection. Not a good idea — uranium releases lethal radon gas capable of causing lung cancer.

Although torbernite can occur it granite, it is highly unlikely that the stone countertops in many kitchens across the globe contain the mineral.

recently released this fast and sensitive HPLC method for the determination of the agricultural herbicides paraquat and diquat in environmental waters that takes less than 10 mins and, in addition, offers the advantages of full automation, the absence of operator influence, time savings, and strict process control!
Paraquat and diquat are widely used to control crop and aquatic weeds, and frequently contaminate drinking and environmental waters due to run off and soaking into ground water. Their presence in both types of waters are monitored and regulated by regulatory agencies as both herbicides are considered a risk factor for liver, heart, lung, and kidney illnesses.
The method described in Application Note 1051, Sensitive and Rapid Determination of Paraquat and Diquat in Tap and Environmental Waters, (link to downloadable PDF) uses on-line solid phase extraction (SPE) and achieves method detection limits that meet the requirements of both the U.S. Environmental Protection Agency Method 549.2 (link to downloadable PDF) and the European Union 98/83/EC (link to page to download method). The application note includes a flow diagram showing the schematic for the on-line SPE setup.
The HPLC column (Thermo Scientific Acclaim Trinity Q1 column) used in the method has been specifically designed for the separation of the herbicides and provides sufficient retention, excellent resolution, and good peak shape for these herbicides. The method was easily accomplished using our dual rapid separation HPLC system (Thermo Scientific Dionex UltiMate 3000 x2 Dual RSLC system).