A Primer on HPLC Flowmeters

High performance liquid chromatography – HPLC – is very often the method of choice for analyzing pharmaceutical compounds starting with R&D and continuing into manufacturing.  Among other things it is used to

  • Check candidate drugs for purity
  • Monitor changes in pharmaceutical intermediates during chemical synthesis scale up
  • Test the stability and dissolution of formulations in development and
  • Support quality control in final drug products

Identifying an analyte by HPLC is based on accurate and reproducible column retention time as it passes through an HPLC system.  Reproducible retention time is critical and depends on uniform, reproducible HPLC pump flow rates.  A leak developing or other malfunction in the HPLC system will result in analysis errors.  Obviously, then, continuous testing is necessary to insure that the HPLC system is properly calibrated.  This is called operational qualification. OQ starts before the HPLC system is put into use and as part of ongoing system … Read the rest

An Ultrasonic Cleaner Design for Food Laboratories

Food laboratory technicians charged with cleaning sieves used to inspect raw materials for correct grain size may welcome a specially designed ultrasonic cleaner developed by acoustic R&D engineers at Elma Ultrasonic in collaboration with food lab personnel  at two locations.   

The result of this collaboration is the Elma S50R ultrasonic cleaner available from Tovatech.  It is optimized for sieve cleaning, but also for degassing HPLC solvents and for sample preparation involving difficult-to-dissolve substances.   A unique feature of the S50R is its built-in programming:  food scientists can select three programs by pressing the corresponding key on the cleaner’s control panel:  sieve cleaning, degassing and sample prep. There is also an on-off key for standard cleaning and a timer showing set and remaining time.

Sieve Cleaning Challenges Solved

While ultrasonic cleaning is safer and gentler than using brushes to dislodge particles trapped in lab sieves thoroughness has been a problem due to … Read the rest

How Ultrasonic Cavitation Bubbles Scrub

Pardon us for the take-off on a well-advertised household cleaner.  We have many posts describing how the implosion of cavitation bubbles in an ultrasonic cleaner solution removes contaminants from wetted surfaces. Here we’ll take a look at what happens at the bubble/surface interface in an ultrasonic cleaner.

Airless Bubbles

Let’s start by saying that unlike the household cleaner bubbles cavitation bubbles have no “air” inside.  Instead they have a vacuum.  The nitty-gritty of how is not as important as what happens.

Except to say in brief, cavitation bubbles are created by ultrasonic transducers bonded to the bottom and/or sides of the ultrasonic cleaner tank.  The generator-driven transducers cause a vibration on the tank surface to produce sound waves in the cleaning solution.  This causes compression and expansion in the liquid leading to cavitation bubbles that implode violently and produce shock waves radiating from the site of the collapse.

What is … Read the rest

How to Remove Jewelry Polishing Compounds

Watch case manufacturers, class ring manufacturers, earring manufacturers, body jewelry manufacturers and other quality jewelry manufacturers with broad markets can quickly and efficiently remove jewelry polishing compounds with an industrial ultrasonic cleaner.  Following the removal of jewelry polishing compounds final cleaning can be accomplished with the ultrasonic cleaner and/or steam cleaning before products are shipped.

Why Ultrasonic Jewelry Polish Removal?

In a word: efficiency.  Ultrasonic cavitation, the implosion of microscopic bubbles against the surface of the jewelry, safely and quickly dislodges and carries away jewelry polishing compounds and other dirt from all surfaces including those difficult or impossible to remove by manual methods.  The action is performed in an ultrasonic cleaning tank filled with a biodegradable cleaning solution excited by ultrasonic transducers powered by a generator.

An example of an ultrasonic system to remove jewelry polishing compounds is the dual-frequency Elmasonic X-tra basic line available from Tovatech.  It is available … Read the rest

How to Comply with New CDC Vaccine Storage Guidelines

Ongoing instances of vaccine spoilage due to improper storage and inattention to expiration dates has prompted the CDC to issue its “Interim Vaccine Storage and Handling Guidance.”

The CDC guidance and related documents are designed to help healthcare facilities plan procedures and equipment procurement related to the storage of vaccines.

Compliance is particularly important if clinics participate in government-sponsored vaccination programs such as Vaccines for Children. CDC is currently evaluating the most efficient and cost effective method to phase in the recommendations.  More guidance is coming.

CDC Vaccine Storage Guidelines; Tovatech Suggestions

We summarize the current CDC document here with our own suggestions on how healthcare facilities and clinics can take steps to protect their investment in vaccines from the time of receipt to administering.


Use a biosafe glycol-encased probe or a similar temperature-buffered probe rather than measuring ambient air temperatures; provide a hi/low alarm system to alert personnel … Read the rest

How to Avoid Analytical Balance Weighing Errors

The Kern ABT analytical balance with automatic internal calibration
The Kern ABT analytical balance with automatic internal calibration

Precision weighing with an analytical balance requires care and alertness on the part of the operator. Many factors can influence the performance of an analytical laboratory balance.  Where precision is paramount an error of 0.001gram or smaller can be significant when strict regulations apply.

How Lab Balance Errors Occur

In simple terms, digital analytical balance errors arise when the instrument inaccurately records the weight of the sample due to influences that can occur without the operator’s knowledge, or because of poor weighing practices.  Influences can be external or internal.

Although externally induced errors can be caused by many factors, they are easy to reduce or eliminate.  Usually these causes are traced to lapses in precision balance operating procedures relating to the sample and the laboratory environment.  Here are some suggestions on reducing external sources of balance weighing errors.  Note that some … Read the rest

How to Position Parts in an Ultrasonic Cleaner

Correct parts positioning in an ultrasonic cleaner is as important as the ultrasonic cleaning frequency and ultrasonic cleaning solution formulation.  Yet of these three criteria improper parts positioning is often the cause of unsatisfactory results or extended time in the cleaning solution.

Don’t Fight Cavitation

Better said, don’t impede cavitation action.  Cleaning is accomplished by the violent implosion of minute bubbles created in the cleaning solution by ultrasonic transducers.   The cleaning action occurs on all surfaces wetted by the solution as sound waves migrate upward through the solution from the bottom of the ultrasonic cleaner tank and reflect back down from the solution surface. This suggests that putting too much product in the cleaning baskets is not a good idea because it will impede sound reflection.  At Tovatech we recommend a 1 to 2 inch space between the tank walls and parts in the basket.

Related to this, strive to … Read the rest

Maintaining Technical Cleanliness

An important quality control procedure in the automotive and similar industries is determining if certain components meet standards for technical cleanliness.  These standards relate to the presence or absence of residual contamination on parts after they have been formed, welded, and/or machined as the case may be.

Ultrasonic cleaners are commonly used to clean parts by removing contamination by cavitation action.  An ultrasonic cleaner is also a critical component in an exacting process to determine the amount and nature of residual contamination that may remain on the product after manufacturing.  Information on this is contained in our post on determining technical cleanliness.

Preventing Post-Cleaning Contamination

Once procedures are in place to produce components that pass the cleanliness test the objective is to prevent post-cleaning contamination.  While this may seem a no-brainer there are many instances where handing acceptably clean components re-introduces contaminants to the surfaces.  Additional procedures should be in … Read the rest

Tips on Ultrasonic Rinsing Systems

Here at Tovatech we get many questions on selecting correct ultrasonic cleaners and ultrasonic cleaning solutions.  Sometimes overlooked by customers and prospects is the importance of rinsing the products after they emerge from the ultrasonic cleaning bath.  In fact, in many instances, especially with precision or delicate products, ultrasonic rinsing is just as important as the cleaning operation itself.

Why Consider Ultrasonic Rinsing?

Well, maybe you don’t have to.  Certain parts such as carburetors or oil pumps may not be affected by the small amounts of cleaning solution residue that remains when they are removed from biodegradable water-based ultrasonic cleaner baths.

At the other extreme surgical instruments, PCBs and similar high-precision products must be thoroughly rinsed for sanitary and performance reasons.   In a sentence, the standards that apply to the cleanliness of the product will guide the selection of your rinsing procedures.

Fortunately a variety of rinsing options are available. … Read the rest

Use a Portable Halogen Moisture Analyzer to Save Money

The compact, portable IL 50.001 halogen moisture analyzer
The compact, portable IL 50.001 halogen moisture analyzer

If you perform moisture analysis at more than one location in your facility you’ll soon see the value in the IL 50.001 halogen moisture analyzer now available from Tovatech.  What makes it attractive is its portability – instead of buying multiple halogen moisture analyzers simply pack the IL 50.001 in its custom carrying case and take it to the test location.

Moreover, you’ll find this 50 g capacity moisture balance easy to use because programming choices have been confined to the basics – a feature that has a side benefit in terms of attractive pricing.

Superior Performance in a Halogen Moisture Analyzer

Attractive pricing is not at the “expense” of superior performance in this compact, 5-pound 120-volt moisture analyzer.  Only 6.5” wide, 11” deep and 5” high, it offers the following performance specs:

  • Readability: 0.001 g, 0.01% moisture
  • Repeatability: 0.3% (3 g
Read the rest