| Meeting tough FDA standards for HPLC system IQ | | | | free-standing and stack system options are the most |
| OQ PQ validation as well as ongoing PV (performance | | | | commonly used although in some instances an |
| verification) calls for properly installed, calibrated, and | | | | adapter kit can be employed to mount the unit on |
| maintained equipment. A digital liquid hplc flowmeter | | | | wide necked reagent bottles. |
| such as the FlowCal 5000 is proven to be a | | | | While GLP requires annual recalibration, flow meter |
| convenient and accurate tool to calibrate HPLC pump | | | | accuracy can quickly deteriorate with improper use. |
| flow rates, simplifying the calibration and validation | | | | For example, dirty sensing tubes can trap bubbles |
| procedures. Pump flow rates from 25 mL/min down | | | | and create false readings. In cases where bubbles are |
| to as low as 0.05 ml/min can be measured with an | | | | observed during operation the quick remedy is turning |
| accuracy of ± 1 % of the flow rate. This type of | | | | the meter off and letting it drain, then return it to |
| tool saves time and labor compared with using a | | | | operation. This suggests that the number one rule is |
| timer while manually collecting the effluent for | | | | to keep the sensing tube clean using supplied |
| measurement by weight or volume. In addition, the | | | | equipment for this important function. Another good |
| data collected is independent of operator technique | | | | practice is to institute a standard operating procedure |
| and is therefore both more accurate and more | | | | specifying that flow meters be cleaned every two |
| precise. | | | | weeks when they are in constant use. Flow meters |
| When checking into digital HPLC flow meters | | | | such as the FlowCal 5000 are shipped with a cleaning |
| laboratory technicians should determine if the models | | | | kit and directions for carrying out this function, a |
| being considered will deliver accurate data at the flow | | | | procedure that is usually completed within 15 to 30 |
| rates typically used and have a traceable calibration | | | | minutes. If flow meters are not to be used over a |
| certificate. In addition, the flow meter must be | | | | week or more they should be flushed with ethanol to |
| compatible with all brands of HPLC systems used in | | | | prevent algae growth. |
| the lab. All wetted parts should be able to safely | | | | Record Keeping |
| handle common HPLC solvents. The flow meter | | | | One method to archive data in order to properly |
| should have an appropriate interface such as an | | | | respond to FDA inquiries involves connecting the flow |
| RS232 port for connection to a printer or PC for | | | | meter to a PC using the RS-232 interface. This allows |
| printing and archiving in accordance with good | | | | operators to record flow meter readings |
| laboratory practices (GLP). | | | | electronically, such as in an Excel document using the |
| Installation and Maintenance | | | | Windows HyperTerminal program. The process |
| Although they are highly accurate, digital flow meter | | | | collects data and displays it using HyperTerminl.exe, |
| performance is adversely affected by improper | | | | copies it on a clipboard and pastes it into Excel for |
| mounting and poor maintenance. Citing the FlowCal | | | | analysis. Step-by-step details for this process are |
| 5000 as an example, several mounting configurations | | | | available from FlowCal equipment providers such as |
| are available and supported by hardware supplied | | | | Tovatech. |
| with the unit. Regardless of the mounting method, | | | | To support labs that choose this approach, some |
| the unit must be within 10 degrees of vertical and | | | | HPLC flow meter suppliers offer an optional miniature |
| with suitable space available for placing the collection | | | | thermal printer to record all readings and error |
| vessel below the flow meter. Wall mounting, | | | | messages output via the RS 232 interface. |