Author Archives: Rachel Kohn

About Rachel Kohn

So how did an MIT Ph.D. end up selling refrigerators? When I figured out that a lot more scientists buy lab refrigerators than innovative leading-edge instruments. I hope that my many years of lab experience will help you find the right equipment for your work. Before co-founding Tovatech I worked in business development and project management at Smiths Detection, Photon-X, Cardinal Health, and Hoechst Celanese. And before that I spent 12 years as an R&D chemist at Hoechst Celanese and Aventis working on advanced drug delivery systems, polymer films and membranes, optical disks, and polysaccharides. Some day, eventually, I’ll make enough money to develop an innovative technology that will change the world.

How to Select a Moisture Analyzer for Low-Moisture Plastic Resins

DSC 71P Moisture Analyzer

DSC 71P Moisture Analyzer

When you select a moisture analyzer for low-moisture plastic resins you will need a model that that not only can quickly but also accurately gauge the moisture content of these resins.   And as with many quality control requirements that involve moisture content, you’ll want a moisture balance that can meet standards set by trade associations and professional organizations.

In this post you’ll get a briefing on the following:

  • why low moisture content is important in plastic resins
  • a technical standard that applies to determining moisture in plastics
  • how benchtop moisture analyzers work
  • a standards-compliant moisture analyzer
    for plastic resins

Why Low Moisture Content is  Important

Owners of injection molding companies and operators of injection molding machines are aware that incorrect moisture content in plastic resins can result in an inferior finished product. 

Product shipped from resin suppliers may have the specified moisture content but ambient conditions … Read the rest

How to Select Ultrasonic Cleaner Accessories

Ultrasonic cleaner accessories

Ultrasonic cleaner accessories

Think of selecting ultrasonic cleaner accessories as though you are buying a new car.  You have the choice of standard equipment and equipment or features that are “optional at extra cost.”

The “options” largely depend on the ultrasonic cleaner manufacturer.  This is why it is important for you to have a clear understanding of what you want to accomplish in your ultrasonic cleaning process.  Our post on ultrasonic cleaner application ideas provides a good tutorial on this.

This post is designed to help you select ultrasonic cleaning accessories that are either required to help you quickly and successfully accomplish your ultrasonic cleaning tasks or simply “nice to have.”

Similarly this post does not go into detail on selecting a specific ultrasonic cleaner.  That is generally based on the size of your operations and what you intend to do with the equipment.  We cover this topic in our … Read the rest

How to Select an Ultra-Low Temperature Freezer

Norlake Select ultra-low freezers have 5 internal compartments

Norlake Select ultra-low freezers have 5 internal compartments

A lot of thought should go into specifying an ultra-low temperature freezer and this post is designed to help you sort through the considerations that apply.  These units are not inexpensive; their function is to protect contents of high value and sometimes for long periods of time.  Fortunately, there are a number of ultra-low temperature freezers on the market to ease the selection of a model that best suits your needs.

What is Meant by Ultra-Low Temperature?

Good question.

There are freezers, low-temperature freezers and ultra-low temperature freezers on the market.  Here are some examples that apply to scientific (not commercial or household) freezers.  Note that different manufacturers may define the temperature capabilities of their various models differently.

  • Scientific laboratory and pharmacy freezers can control ranges from -10⁰ to -25⁰C (+14⁰ to -13⁰F)
  • Low temperature freezers, depending on the model and function:
Read the rest

How to Select a Stability Test Chamber

Knowing how to specify a stability test chamber calls for a clear understanding of what stability test chambers do, how they relate to the various components or ingredients that go into the product you manufacture and where these products are used. 

In this post we’ll provide some examples of things to consider when specifying a stability test chamber then share suggestions on what to look for in this critical equipment. 

As a refresher or for readers new to the subject here is an answer to what constitutes a stability test chamber.

What is a Stability Test Chamber?

Most stability test chambers resemble a large scientific refrigerator.  Only instead of keeping contents cool, their function is to replicate variations in temperature, humidity and light over long periods of time. This is critical when pharmaceutical companies, for example, wish to bring new products to market. 

It has everything to do with … Read the rest

How to Calibrate Flow Meters for HPLC Pumping Systems

Calibrating a flow meter for HPLC pumping systems is best left to the experts.  Do not try it at home. But since you landed on this post, we’ll tell you how it is done by the experts. 

HPLC Flow MeterExperts are required to calibrate flow meters for high performance liquid chromatography (HPLC ) pumping systems because it is an exacting exercise involving a high-precision measuring instrument. We’ll explain why in a bit.

But first, a brief introduction to flow meters in general.  If you are familiar with flow meters you can skip to how they are calibrated for HPLC systems.

What do Flow Meters Do?

As the name implies, flow meters measure the rate of flow of a product, usually through a pipeline or processing line.  Gasoline pump flow meters at your local filling station are another common example.  Standards may apply to periodic certification by calibrating flow meters to confirm that … Read the rest

How to Select the Best Flammable Liquid Ultrasonic Cleaner

Ultrasonic Cleaning with Flammable LiquidsFlammable liquid ultrasonic cleaners may often be required when contaminants are difficult to remove and where residues that may remain after using conventional water-based biodegradable cleaning solutions are unacceptable.  Flammable liquid (also called volatile solvent) ultrasonic cleaners can overcome these challenges as we will explain later in this post.

But first a short tutorial.

What is a Flammable Liquid?

They are not all exactly the same.  Flammable liquids have different flashpoints. In brief, the lower the flashpoint the more flammable they are, which is an important consideration when specifying an ultrasonic cleaner for flammable liquids.  

The American Chemical Society publishes a table of  common organic solvents that includes flash points.  Examples of low flash point volatile solvents are 1-propanol at 59⁰F, acetone at -4⁰F and toluene at 39⁰F.  Solvents with higher flashpoints include NEP (N-Ethyl-2-pyrrolidone) or NMP (N -Methyl-2-pyrrolidone) at or above 131˚F.

It’s the Fumes, Stupid!

In chemical terms … Read the rest

How to Choose a Lab Refrigerator or Freezer

How to Choose a Lab Refrigerator or FreezerSelecting a laboratory refrigerator or laboratory freezer is not the same as visiting the local appliance store to pick out a unit for your kitchen.  There are substantial differences.  Not only that, there is a tremendous variety of models available in terms of capacity and performance features. 

This post quickly describes differences between household and laboratory refrigerators and freezers. Then we’ll looks into the many feature options available and help you select the model that meets your requirements.

How to Pick the Best Ultrasonic Cleaner

Selecting the Best Ultrasonic CleanerTips on Selecting the Best Ultrasonic Cleaner

So, you’ve landed here because you’ve heard about ultrasonic cleaning and how wondrous it works in removing almost any contaminant from almost any surface that can be immersed in an aqueous cleaning solution.  The task you have now is how to select the best ultrasonic cleaner for the cleaning challenges you have in mind. 

Here we offer some useful suggestions.

Why Selecting an Ultrasonic Cleaner is Important

If you’re interested in selecting an ultrasonic cleaner for your cleaning operations you’ve probably done a bit of research and found that choices seem endless.  The range of sizes, shapes, features and pricing is further complexified (our word) by prices for the units.  How do you select an ultrasonic cleaner and be assured that it will do the job you expect of it?  

This post does not get into pricing.  What we hope to do here … Read the rest

How to Select an Ultrasonic Cleaning Solution

ultrasonic_cleaing_solution_selection_v3Benchtop and industrial ultrasonic cleaners provide outstanding cleaning results in thoroughness and speed for applications from watch making to jet engine components and virtually anything in between that can be safely wetted.  Largely responsible for this is the variety of ultrasonic cleaning solutions provided by manufactures to target both broadly defined and highly targeted cleaning challenges. Selecting the right ultrasonic cleaning fluid is not a hit-or-miss proposition.  Several considerations come into play.  

Ultrasonic Cleaning Solution Selection Tip No.1

What is the contaminant?  Put another way, what do you want to remove by an ultrasonic cleaning process?  Examples include

  • grease, grime and grit on engine and drive train components
  • salt and other residues on scuba gear
  • soldering residues and other contaminants on PCBs
  • burned on plastic injection mold deposits
  • grit and grime on cherished vinyl LP records
  • contaminants on surgical and dental instruments
  • tarnish or old paint on brass, copper and
Read the rest

How a Digital HPLC Liquid Flow Meter Works

HPLC Liquid Flow MeterBefore explaining how HPLC liquid flow meters work here’s an explanation of what digital HPLC flow meters do:  Digital HPLC flowmeters are used to measure the accuracy of High Performance Liquid Chromatography pumping systems in order to meet FDA and other regulations regarding installation qualification (IQ), operational qualification (OQ) and performance qualification (PQ) of equipment used in the pharmaceutical and biopharmaceutical industries as well as other analytical labs.

The process demands accurate, reproducible column retention time as an analyte (what is being analyzed) is pumped through the HPLC system.

These precision instruments are not to be likened to flow meters used on process lines measuring flow rates in, for example, thousands of gallons per minute but instead in fractions of milliliters per minute.

Why HPLC Pump System Accuracy is Important

As suggested above, meeting regulations (and protecting a company’s reputation) is the reason.  Consistent accurate performance is an absolute necessity. … Read the rest