NVG-10 BURETTES WITH STRAIGHT BORE PTFE (TEFLON) KEY STOPCOCK

Design and Features

The NVG-10 burette is a high-quality, precision instrument made from borosilicate glass, which is highly resistant to thermal shock and chemical corrosion. The burette has a long cylindrical body, marked with graduations along its length to allow precise readings of the liquid volume being dispensed. The graduations are often printed with high-contrast ink, which makes reading measurements easy and minimizes the risk of parallax errors.

The distinguishing feature of this burette is its straight bore stopcock made from PTFE (Polytetrafluoroethylene), commonly known by the brand name Teflon. PTFE is well known for its excellent chemical resistance, non-stick properties, and high tolerance to temperature variations. This makes the NVG-10 burette ideal for use with a wide range of reagents, including acidic, basic, and organic solutions, as PTFE is virtually inert to most chemicals found in laboratory settings.

The straight bore design of the stopcock allows the liquid to flow smoothly through the valve, reducing the potential for blockages or irregularities in dispensing. The stopcock can be easily rotated to control the flow rate of the liquid being dispensed, allowing for fine control during titrations. The PTFE stopcock is also leak-proof, providing confidence in accuracy and ensuring no loss of solution during use.

Uses and Applications

The NVG-10 burette with a PTFE key stopcock is primarily used for volumetric analysis, particularly in titration experiments. Titration is a common analytical procedure used to determine the concentration of a solution by reacting it with a solution of known concentration, called a titrant. The burette’s accuracy and easy control make it essential for various laboratory applications, including:

1. Acid-Base Titrations: Acid-base titrations are among the most common uses of the NVG-10 burette. In these experiments, the burette is used to accurately dispense an acid or base solution into a flask containing the analyte and an indicator. The precise control offered by the PTFE stopcock allows the titrant to be added dropwise as the endpoint is approached, ensuring the reaction is stopped at the exact point where neutralization occurs.
2. Redox Titrations: Redox titrations involve the transfer of electrons between reactants and are used to determine the concentration of oxidizing or reducing agents in a solution. The NVG-10 burette is particularly suitable for dispensing the titrant in redox reactions, where precise volume control is necessary to accurately determine the equivalence point.
3. Complexometric Titrations: In complexometric titrations, a chelating agent, such as EDTA, is used to form a complex with metal ions. The NVG-10 burette is used to dispense the chelating agent while monitoring the formation of the complex, typically with the use of an appropriate indicator. The accuracy of the NVG-10 ensures that even trace concentrations of metal ions can be accurately determined.
4. Quality Control in Industrial and Research Settings: Industries such as pharmaceuticals, food and beverage production, and water treatment often rely on titration for quality control and product analysis. The NVG-10 burette is ideal for these settings, providing the precision needed to ensure that products meet stringent quality and safety standards.

Advantages of PTFE (Teflon) Key Stopcock

The PTFE key stopcock is a critical feature of the NVG-10 burette that provides several advantages:

1. Chemical Resistance: PTFE is highly resistant to a wide range of chemicals, including strong acids, alkalis, and organic solvents. This ensures that the stopcock remains unaffected by the chemical reagents being dispensed, reducing the risk of degradation or contamination. This chemical resistance makes the NVG-10 burette versatile and suitable for use with a wide range of reagents.
2. Smooth and Reliable Flow Control: The straight bore design of the PTFE stopcock ensures a smooth, unrestricted flow of liquid. The non-stick properties of PTFE minimize friction, allowing for easy and precise adjustments to the flow rate, which is essential during titration. This smooth control is particularly useful when approaching the endpoint, where dropwise addition of the titrant is required.
3. Leak-Proof Operation: The PTFE stopcock is designed to provide a secure, leak-proof seal. This prevents loss of the titrant and ensures the accuracy of the titration process. The tight seal also minimizes the risk of contamination by preventing external substances from entering the burette.
4. Ease of Cleaning and Maintenance: PTFE is easy to clean due to its non-stick properties. Residues from previous experiments do not adhere to the PTFE surface, making it easy to rinse and clean the stopcock between uses. This feature helps to maintain the accuracy and reliability of the burette over time.

Calibration and Accuracy

The NVG-10 burette is calibrated to ensure high accuracy, which is crucial for titrations and other volumetric analyses. The graduations are marked clearly, allowing the user to accurately measure the volume of the dispensed liquid. The accuracy of the burette is often expressed as a percentage of the total volume, and the NVG-10 burette typically meets or exceeds the standards required for Class A accuracy. This level of precision is vital in quantitative analyses where even a slight deviation in volume could lead to incorrect results.

Handling and Maintenance

Proper handling and maintenance of the NVG-10 burette are crucial to ensuring its longevity and accuracy:

1. Cleaning: After each use, the burette should be thoroughly cleaned to prevent any residues from affecting future titrations. The PTFE stopcock can be easily removed and cleaned separately to ensure that no chemicals are left inside the bore. For cleaning, the burette should be rinsed with deionized water, followed by the solvent appropriate to the reagents used.
2. Storage: The burette should be stored in an upright position to prevent the stopcock from becoming damaged or blocked. It is also essential to keep the stopcock open when not in use to avoid unnecessary stress on the sealing surfaces.
3. Calibration Check: Regular calibration checks are recommended to ensure that the burette maintains its accuracy. Calibration should be done periodically or if the burette is suspected to be inaccurate.