Bottle-mounted FlowCal 5000 HPLC Flowmeter

A CNNMoney article in August 2010 stated that recalls of prescription and over the counter drugs are surging, raising questions about the quality of drug manufacturing in the United States. The article mentioned FDA reports of more than 1,742 recalls in 2009 up from 426 in 2008. Because HPLC (high performance liquid chromatography) is frequently the method of choice for analyzing pharmaceutical compounds from research through development and manufacturing, HPLC systems should be regularly checked for consistency and accuracy by using a digital HPLC flowmeter. 

The role of factory-calibrated HPLC flow meters such as the FlowCal 5000 available from Tovatech is relatively simple but also highly precise.  It is used to identify malfunctioning valves and seals in HPLC flow systems that can lead to inaccurate formulations.  The FlowCal 5000 is a fast and accurate tool to support HPLC calibration and HPLC validation.  Record-keeping is simplified by transferring HPLC pump test data to a PC.

How the FlowCal 5000 Digital Flowmeter Simplifies HPLC Validation

The FlowCal 5000 flowmeter is used at the end of a flow system to measure the pump output rate.  It contains a glass tube (140 µL in volume) with two optical sensors.  As the liquid meniscus passes the first sensor it actuates a timer.  When the liquid fills the tube and the meniscus passes the second sensor the time is calculated and displayed.  A valve is opened to drain the tube.  This process continually repeats, each time refreshing the digital reading.  Other characteristics include:

• A single chip microcontroller displays flow rate from 0.05 to 25 ml/min rounded to 4 digits
• Measuring is by volume independent of liquid type up to a viscosity of 10 centipoises
• Data are transferred as a 6-digit reading for archiving via an RS232 interface
• It is supplied gravimetrically calibrated at customer-specified flow rates
• It works with any HPLC pump

The FlowCal 5000 UKAS (NIST-equivalent) traceable single point flow calibration certificate is supplied as standard to comply with government standards including the FDA.  Standard calibration is at 1 ml/min. Calibrations at customer-specified flow rates are also available.

Mounting and Maintaining your FlowCal HPLC Liquid Flow Meter

A precise instrument, the FlowCal 5000 digital flow meter must be properly mounted in order to give accurate results.  Regardless of how it is mounted the device must be within 10 degrees of vertical.

Several mounting options are available.  Instructions and hardware come with the kit.  For example:

1. it can be wall mounted using the supplied L-shaped brackets
2. with the a base plate and adhesive feet it can be free standing on a work counter
3. the stack system mounting option allows placement of the flowmeter on the left, front or right side of the stacked pump and detection system
4.  the bottle top adapter lets you mount the flow meter directly onto wide-necked reagent bottles

Maintenance requires regular cleaning of the sensing flow tube using the supplied cleaning kit and directions.  This is accomplished without disassembly of the sensing tube, an action that will invalidate the factory calibration. 

HPLC Calibration

Initial HPLC calibration is performed by the manufacturer.  Recalibration of the flowmeter should be done on an annual basis or if there is reason to suspect that it is not performing properly.  This procedure should not be done in house.  Instead the FlowCal 5000 digital liquid flow meter should be returned to Tovatech for recalibration.   

In summary, the digital FlowCal 5000 flow meter is a quality control tool to confirm uniform and reproducible HPLC pump flow rates in laboratories and manufacturing facilities, and to support GLP and GMP. These precision instruments must be properly mounted and maintained.  Permanent record-keeping is essential.  Contact the scientists at Tovatech for information on using digital flowmeters in your facility.

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How do you measure the accuracy of HPLC equipment in your lab or manufacturing operation?  Is information on using and maintaining equipment available in your operations manual?

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