If the Micro Balance show “————-” display, it means balance is busy. Hazardous materials must be handled in an enclosure having appropriate air filtration. Use containers of size such that the loading capacity of the balance is not exceeded. Weighing read with four decimal places is preferred for weighing near-gram quantities. USP General Chapter 41 (Balances) General Chapter 41 sets three distinct requirements to be applied to materials that must be accurately weighed. Each type of material requires its own special handling. Official 1st Dec 2013, can be applied 3rd June 2013. The following methods are acceptable for good analytical results. Place the empty butter paper / or receiver on the balance in the center of the pan, and press the appropriate tare (Zero) key on the balance (On stabilization of indicator). Many chemicals, such as salts, are corrosive, and materials of this nature should not be spilled on the balance pan or inside the balance housing. Weighings are made on many different types of materials, such as large solids, finely divided powders, and liquids (viscous or nonviscous, volatile or nonvolatile). Repeatability should not be more than 0.001 or 0.10% and the measurements should be within ± 10% or 0.0010. of the actual weight. Add the material to the receiver, slowly so maximum require the volume to the vessel. All other things being equal, a vessel of low mass should be chosen when small amounts of material are to be weighed. USP <791> specifies a minimum of two calibration points. In case the weight prints taken are not considered in the calculation ( e.g due to  unclear  visibility, misprinting, not as per defined statistics mode or weighing mode, etc.). Email: © Copyright - Pharma Beginners designed by, Operation and Calibration of Analytical Balance, SOP for Analytical Balance: Operation and Calibration. Weighing is usually done by difference. Note: In case the calculated standard deviation of 10 replicate measurements is smaller than0.41d value then replace the standard deviation value with 0.41d value. Adjust the level, if not leveled. Fine powders have a tendency to pick up static charge, which will cause the particles to fly around. Perform 10 measurements with the exact same weight; Calculate 2 x the standard deviation (std. Over an extended period of time, balance drift and other day-to-day variations are monitored by weighing a fixed check-weight on a regular basis; this check should be performed after the balance has been calibrated at the ambient laboratory temperature. Put the external weight of 200 g on the pan and note the measurement in the template (Annexure-2). Before weighing or calibration, the balance should exactly in a horizontal position (check the level indicator, which should be in the center). If print facility available attach the print out with a template. QUALITY ASSURANCE PROCEDURE FOR MEASUREMENT OF BALANCE DRIFT. If stretching of the springs is excessive, an expensive balance overhaul may be needed. If the calibration status label is not provided by the certified agency then affix the label on the weight box as per. The balance is placed in a suitable location with sufficiently low levels of vibration and air current. The spilled material must be properly disposed of and must not be swept out onto the balance table where other operators may come in contact with the chemical. The analyst shall always use the calibrated weight box for calibration purposes. Switch ON the balance. Every time after calibration of weight box format of. In addition, the tolerance does not correspond to the value of 0.1%, specified under Weights and Balances 41, for weighing material accurately. They are recommended for calibration of balances using optical or electrical methods for accurately weighing quantities below 20 mg. The second weight represents the sum of the weights of the receiver and the untransferred material; subtract this sum from the sum of the total material weight and the receiver weight to determine the weight of the transferred material. Tare the empty receiver as follows. As per the mandatory requirements, a weighing balance should be calibrated on a daily, weekly and monthly basis. USP General Chapter 41 (Balances) sets three distinct requirements to be applied to materials that must be accurately weighed. Calibration and Performance of a Conductivity System to Meet USP 23 page 4 of 11 Thornton Associates February 1, 2002 The advantages of on-line conductivity testing have been exploited serving pharmaceutical water systems for many years. Sign the printout with the date and paste in the calibration template and complete the entry in Annexure-1. If the standard deviation obtained is less than 0.41d, where d is the scale interval, replace this standard deviation with 0.41d. A balance weight makes a reliable check-weight. Take extra care to weigh such type of material. Check the sample, the balance, and the laboratory environment for the following causes of errors, and eliminate them: Temperatures of the balance and the material to be weighed are not the same. Small quantities of viscous liquids can be handled by touching a glass stirring rod to the surface of the liquid and then carefully touching the rod to the side of the receiving vessel, which allows some of the material to be transferred. SOP for Maintenance of Laboratory Instruments; USP<1251> Weighing on an analytical balance. With 65 years experience in the scale industry, we provide the highest quality service and products for all of your weighing needs. It is important that the balance to warm up for initialization 30 minutes proceeding! “ on ” in pharmaceutical field press the “ print ” key to get on. 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