XPR Automatic Balance

METTLER TOLEDO’s XPR Automatic Balance is an automatic weighing system that dispenses powdered samples and liquids directly into a container on the balance weighing pan. It can also be used to create solutions with highly accurate concentrations. The dispensing is carried out automatically; simply enter the amount you want to dispense, and the Automatic Balance will do it for you.

Yes, the XPR Automatic Balance can be used for both automated weighing and traditional manual weighing. To change from the automatic powder dispensing system, simply click once on the relevant icon and the dosing head moves to its uppermost position, leaving plenty of free space in the weighing chamber for your manual weighing applications.

Automatic powder dispensing is more accurate than manual weighing. The XPR Automatic Balance dispenses a fine stream of powder particles, allowing the desired sample quantity to be dispensed with a high degree of accuracy and with exceptional repeatability. Manual dosing processes are subject to a high degree of variability, not only because of the influence of the operator, but also due to factors such as opening and closing the draft shield, which causes drafts and temperature fluctuations that can affect accuracy. Achieving the same level of accuracy as the XPR Automatic Balance, with high repeatability, is practically impossible.

METTLER TOLEDO offers a variety of different dosing heads suitable for dispensing powders with a wide range of different particle properties such as size, shape, surface texture, density, and susceptibility to electrostatic charge.

To avoid cross-contamination, one dosing head is dedicated to a single substance or lot number. The dosing head is then mounted on the Automatic Balance. To increase the storage volume, a vial can be attached to the dosing head. The dosing heads are easily interchanged for the automatic dispensing of different powders. To assist in this process, each dosing head has a built in RFID chip, which makes it possible to quickly and easily identify and verify the contents of the dosing head.

When not in use, the dosing head and attached vial can be stored safely as one unit in a dedicated storage box.

Our dosing head guide can help you select the right head according to the characteristics of your various samples.

Quantos Dosing Heads Selection Guide

The XPR Automatic Balance can dispense powders into a variety of different sized vials and bottles as well as capsules. Our specially designed adapters hold your container securely on the balance, while the dosing head has a sensor to automatically detect the top of the container to ensure precise powder dispensing. With the addition of the sample changer, up to 30 samples of different quantities can be dispensed in one run.

Yes, your Automatic Balance can be used to fill capsules of sizes ranging from 000 to 4. Furthermore, by using the sample changer, up to 30 capsules can be filled in one fully automated run.

Automatic Balances (XPRQ models) are supplied with the Q3 dispensing module as standard. The Q3 dispensing module:

• Dispenses powders and liquids
• Utilizes the HeightDetect feature, which automatically detects the correct dosing height
• Connects with the Sample Changer
• Is mounted above the weighing chamber, leaving ample free space for manual weighing and taller vials
• Can be added to all XPR analytical balance models to upgrade to automated weighing as an XPR Automatic Balance

Simple liquid dispensing on your XPR analytical balance can also be achieved through the addition of the QLX3 liquid dispensing module, which still enables you to create highly accurate solutions and concentrations. However, the QLX3 is installed inside the weighing chamber and only offers basic automated liquid dispensing. (Note that the QLX3 does not have the HeightDetect feature and is not compatible with the sample changer or with the XPR106DUH, which has a reduced height draft shield.)

Both the Q3 and QLX3 dispensing modules need to be connected to a pump. Each pump can be connected to up to 3 dispensing bottles to facilitate the dispensing of 3 different liquids. With the XPR Automatic Balance, up to 3 pumps can be connected, enabling you to dispense up to 9 different solvents.

The XPR Automatic Balance uses the weight of the liquid to determine the volume. The density of the liquid in the ambient temperature is required to ensure the calculation is accurate.

Learn more about gravimetric sample preparation in our free white paper:

White Paper: Gravimetric Sample Preparation - Reducing Sample Size and OOS Errors

Yes, your XPR Automatic Balance with the Q3 dispensing module can be used for automatic powder dispensing and automatic liquid dispensing. The XPR Automatic Balance comes with the Q3 dispensing module as standard. For automatic powder dispensing, you will need to purchase the appropriate dosing head(s) according to the particle characteristics of your sample. For automatic liquid dispensing, you will also need a liquid dosing head and at least one pump and bottle. 

In combination with the automatic liquid dispensing accessories, the XPR Automatic Balance enables you to prepare highly precise concentrations down to 0.1 mg/g. To create accurate solutions and standards, the XPR Automatic Balance uses the actual dosed amount of substance to determine the precise amount of solvent needed to obtain the exact concentration you require.

1. Select the automatic solution preparation application
2. Enter the concentration
3. Enter the quantity of solution
4. Place your container on the weighing pan and tare
5. The Automatic Balance dispenses the substance into your container
   • Alternatively, you can dose the substance manually
6. Attach the liquid dosing head
7. The Automatic Balance dispenses the solvent into your container

The XPR Automatic Balance enables you to achieve a dilution factor of up to 10,000 in a single step by automatically dispensing the appropriate quantities of powder and liquid to create the desired concentration. Eliminating intermediate dilution steps drastically reduces the amount of solvent required, which minimizes waste, and results in considerable cost savings.

The highest capacity available on an XPR Automatic Balance is 320 g, which can be achieved with the XPR305D5Q.

The lowest minimum weight of 0.4 mg can be achieved with the XPR106DUHQ Automatic Balance. The automated USP minimum weight with the XPR106DUH is 4 mg.

When you use METTLER TOLEDO’s ErgoClip Vial Adapter or ErgoClip Height Extension accessories, there is no minimum height requirement for your containers. The vial adapters are compatible with all XPRQ Automatic Balance models, including the XPR106DUHQ. Without the ErgoClip, the minimum container height is 75 mm. The ErgoClip Height Extension is not compatible with the XPR106DUHQ, which has a reduced height draft shield.

It is not possible to have the internal ionizer installed at the same time as the Q3 dispensing module. However, the integrable Antistatic Kit for the Automatic Balance can be used to eliminate electrostatic charge in the weighing chamber.

StaticDetect is automatically switched off during automated weighing to avoid any potential disturbance of the dispensing process. StaticDetect works in the usual way during manual dosing procedures, checking for the presence of electrostatic charges and providing a warning if the calculated error breaches the predefined limit.

Vials, bottles and capsules can all be used on the Sample Changer. We offer a range of adapters to accommodate different sized vessels with diameters from 8.5 mm to 52 mm. For containers with a diameter greater than 33.5 mm, only every alternate position on the Sample Changer can be used. We also offer adapters for Falcon tubes (16.4 mm and 29.3 mm), Eppendorf tubes (1.5 mL), and capsules (size 000 – 4).

The speed of dispensing depends largely on the particle characteristics of the powdered sample; free flowing powders can be dispensed faster than powders that have a tendency form clumps. Clearly, larger quantities will take longer to dispense than smaller quantities. The speed of dispensing is influenced by the tolerance limits. When the tolerances are larger, i.e. when a lower level of accuracy is acceptable, the dispensing time is shorter.

Your XPR Automatic Balance can work with asymmetrical tolerance limits. If your container must not be under- or over-filled, simply set the corresponding tolerance limit to 0%.

In the automatic dispensing of small quantities of liquids, evaporation is a key consideration. Evaporation of dispensed liquids can be observed as drifting weight figures on the balance that may be significant enough to prevent the balance from settling. For solvents that evaporate quickly, we would recommend dispensing at least 100 mg (approximately 0.1 mL).

All XPR Automatic Balances are compatible with LabX™. The LabX Balance Instrument License for Excellence balances includes the XPR Automatic Balance.

Explore more about the benefits of LabX:

Streamline processes and reduce system maintenance with LabX™ laboratory software

To ensure the highest accuracy and best performance, the suggested number of doses is 250. However, the heads have been tested to perform satisfactorily well beyond this recommendation. Depending on your application, accuracy requirements, and applicable regulations, the dosing heads can be used as long as they continue to meet your demands. 

The choice of powder dosing head is critical to achieve optimal performance and accurate results. Our dosing head guide provides an overview of the different heads available. Furthermore, our dosing head kit contains a selection of the most commonly used heads, enabling you to try out different heads with your various samples.

You can also send non-toxic powders to our application laboratory, and we will assess which is the most appropriate dosing head. Please contact LabTec Support for further information.

Automatic powder dispensing and automatic liquid dispensing results in considerable savings in sample materials and solvents. Making just one standard per day can give you a return on your investment in the XPR Automatic Balance in as little as 3 months.