Posts by Rachel Kohn
A Moisture Analyzer for Shampoo Quality Control
Most everyone has their favorite shampoo and probably pays little attention to what’s inside the tube or bottle – only that it does a good job cleaning hair. Chances are the thickness of the shampoo is important as well – cheaper brands that are thin and watery usually don’t pass muster. Yet water, specifically deionized water – comprises about 70 to 80% of the shampoo formulation with the actual target specified by the manufacturer. Keeping formulations on target is eased with a moisture analyzer for shampoo quality control.
While formulations vary, the approximately 25% non-water contents of shampoo include detergents and surfactants, foam boosters, thickeners and conditioners. Preservatives and modifiers, fragrances and dyes are typically added to the batch then mixed. After the mixing period samples are sent to the quality control lab. Among other tests QC personnel can use a moisture analyzer to determine that the water content is … Read the rest
How Accurate is your HPLC Pump?
As researchers know a critical if not the most critical aspect of an HPLC pump system is providing uniform and reproducible column retention times as analytes are pumped through a liquid chromatography system. This in turn relies on uniform and reproducible HPLC pump flow rates. After initial operational qualification (OQ) periodic calibration checks of HPLC pump systems must be undertaken to confirm OQ and to identify and correct flow rate variances that may develop due to factors such as worn pump seals or sediments that interfere with flow rates. These calibration tests are performed by checking flow rates while pumping solvent through the HPLC system.
HPLC Troubleshooting – the Hard Way and Easy Way
Several of our posts on the FlowCal 5000 digital liquid flow meter explain how the system works in comparison to manual methods. Taking a paragraph from our Flow Meter Buyers Guide researchers “can measure flow rates … Read the rest
Ultrasonic Cleaner Operating Tips
New ultrasonic cleaners are usually shipped with operating instructions. These may be misplaced. If you purchase a used sonic cleaner the manual may not be included. Improperly using this equipment can quickly damage it, which is why we’re presenting this post on ultrasonic cleaner operating tips. They are not in order of importance because all are important.
These tips are not comprehensive but they do cover a majority of cases. If you have questions please contact us whether or not we supplied the unit.
Cleaning Baskets
Parts being cleaned should never be in contact with the ultrasonic cleaner tank. Why? The ultrasonic vibrations caused by transducers mounted to the tank will cause parts to wear against the tank surface. Eventually this may result in a leak. Instead position what you are cleaning in parts baskets that are designed to fit the tank. … Read the rest
Ultrasonic Nanoparticle Dispersion
Sonication in laboratory ultrasonic cleaners is a widely accepted process for the dispersion or separation of nanoparticles in liquids – that is breaking up nanomaterial agglomerates. It is an effective alternative to other dispersion methods such as rotor-stator homogenizers, piston homogenizers and wet milling. A number of factors should be considered when selecting ultrasonic equipment to break up agglomerates whether you use a solvent-based or aqueous suspension.
As an introduction you must keep in mind that the optimum performance settings of the ultrasonic equipment may vary depending on the agglomerates being dispersed. In other words if you are working with a variety of nanoparticles you should investigate equipment with adjustable operating parameters.
Here we provide some guidelines on ultrasonic equipment selection for nanoparticle dispersion.
Ultrasonic power:
In this case power refers to the ultrasonic power input into the bath. In this post we use the 3-quart capacity dual frequency … Read the rest
Lab Freezer Alarm Crucial to Biological Sample Protection
An October news item reported that a lab freezer door left open at a medical research institute resulted in compromising some 26,000 specimens being used in the study of Parkinson’s disease. The article reported that the required storage temperature for the specimens is at a temperature below -80⁰C (-112⁰F). “This incident along with others mentioned in our posts, clearly indicates human error is an unfortunate cause of such instances and that many if not all losses can be avoided with a lab freezer alarm,” says Tovatech director Dr. Rachael Kohn.
Lab Freezer Alarm Systems
Ultra-low temperature freezers – those designed to maintain temperatures to -86⁰C such as the NorLake Select series available from Tovatech – come equipped with sophisticated alarming systems that signal when a door is left ajar or other temperature excursions that can be caused by power failures. “Indeed alarming systems are … Read the rest
Semi-Micro Analytical Balance Simplifies High Resolution Weighing
The LF-225 DR multi-function dual-range semi-micro analytical balance offered by Tovatech is an ideal solution when highly accurate weighing is required on a regular basis. This balance is crafted in Japan with exceptional quality workmanship. Researchers, jewelers and others can benefit from the readability of 0.01 mg up to a 92 g capacity or 0.1 mg up to a 220 g capacity. Linearity in these ranges is ±0.03 and ±0.02 mg; repeatability is ±0.02 and ±0.1 mg respectively.
The USB port on this Windows® compatible balance simplifies transfer of data to a pc or printer.
Featuring a one-key calibration function the LF-225 DR semi-micro balance has internal weigh chamber dimensions of 6 x 6.25 x 9 inches, an unusually tall space. The novel sliding door mechanism permits users to open the right side glass door with the left hand while placing samples on the weighing … Read the rest
Vaccine Refrigerators for the 2014 Flu Season
The fast-approaching 2014 flu season serves as a reminder for healthcare facility operators to review their vaccine storage practices especially relating to the ability of their vaccine refrigerators to maintain the correct storage temperature. As reported in previous Tovatech posts costs related to loss of vaccine potency due to human error and mechanical failure can be very substantial. Most of these losses occur at the end of the vaccine cold chain – when they arrive at clinics and stored prior to being administered to patients.
Minimizing Vaccine Storage Losses
Human error can be lessened and hopefully eliminated by establishing comprehensive vaccine storage and handling guidelines as suggested in the CDC’s Vaccine Storage and Handling Toolkit. Losses related to improper storage temperatures can be minimized or eliminated when refrigeration equipment is designed to maintain tight temperature tolerances. The proper storage temperature for refrigerated vaccines is provided by the manufacturer but normally … Read the rest
How to Clean Lab Glassware
Cleaning volumetric lab glassware such as burets, pipettes, flasks, and graduated cylinders can be a daunting task for two reasons: laboratory glassware is susceptible to breakage and associated replacement costs, and complex configurations make thorough cleaning difficult. But all lab personnel know this.
The task is made easier with an ultrasonic cleaner – equipment widely used in labs for a variety of reasons. One of these is being an excellent means to thoroughly remove tenacious contaminants from delicate laboratory glass. The secret to effective sonic cleaning lab glassware is selecting the right cleaner, cleaning solution formulation and establishing a consistent cleaning procedure.
Cleaning is accomplished by cavitation action, the implosion of millions of minute air bubbles created by generator powered transducers bonded to the bottom of the cleaning tank and vibrating at ultrasonic frequencies such as 37,000 cycles per second (37 kHz). The imploding bubbles safely and effectively remove contaminants … Read the rest
Ultrasonic Cleaner Maintenance Tip: Tank Discoloration
A Tovatech customer asked us about the cause and removal of a discoloration inside his Elmasonic ultrasonic cleaning tank. The location and size of the tank discoloration suggested to us that it was caused by the heater. We present here a tip on how to prevent discoloration (sometimes called “furring”) and if it occurs how to remove it.
Furring can show up in a variety of colors in an ultrasonic tank. It can occur if the unit’s heater is activated when the ultrasound is not activated. This causes the solution adjacent to the heater to reach very high temperatures resulting in discoloration. (It’s somewhat like placing an empty stainless steel pot on the stove and turning on the burner. You’ll soon get a discoloration.)
So, even though the tank may be filled, if the solution is not circulating there will be a significant temperature differences that can result in discoloration.… Read the rest
An Introduction to Ultrasonic Transducers
Most of our posts on ultrasonic cleaning describe the role of ultrasonic transducers in producing cavitation in the cleaning solution. We thought it would be a good idea to provide a short tutorial on ultrasonic transducer design configurations.
What Transducers do:
Ultrasonic transducers turn electrical energy into mechanical energy measured in thousands of cycles per second (kHz). Benchtop ultrasonic cleaners have transducers bonded to the outside of the bottom and/or sides of the cleaning tank and connected to the unit’s ultrasonic generator. Mechanical energy passes through the tank material – typically stainless steel – to create cavitation bubbles that do the cleaning. Here we’ll briefly describe the types available and variations on those types.
The Piezoelectric Transducer
The term is derived from the Greek piezo, meaning to squeeze or press and electron, standing for amber, which is ancient source of electrical charge. As described in Wikipedia, … Read the rest
