FAQs
What is a tungsten ICP standard used for?
It is a single-element calibration standard containing 1,000 ppm tungsten, used to calibrate inductively coupled plasma (ICP) and atomic absorption instruments and to verify their performance. Accurate standards like this are essential for reliable quantitative measurement of tungsten in trace-metal analysis.
Why does the standard contain trace ammonium hydroxide?
The standard is prepared as 1,000 ppm tungsten in water with a trace of ammonium hydroxide (NH4OH). The trace base helps keep tungsten stable in solution, since some elements require a specific matrix to remain dissolved and avoid precipitation over the standard's shelf life.
What do the CAS numbers refer to?
The LabPro listing gives CAS numbers 7732-18-5 (water), 11120-25-5 (the tungsten source), and 1336-21-6 (ammonium hydroxide), reflecting the components of the standard's matrix. Confirming these helps ensure you have the correct standard and lets you reference the Safety Data Sheet for handling.
What sizes are available?
The standard is offered in 100 mL and 500 mL sizes. Choosing a size that matches your calibration throughput helps manage shelf life, since standards are best used within a reasonable period after opening to maintain their certified concentration for accurate results.
How should the standard be stored?
Store the standard according to the manufacturer's guidance on the Safety Data Sheet and the certificate, keeping the container closed to avoid contamination or evaporation that could shift the concentration. Proper storage preserves the certified value so your calibrations and quality-control checks remain accurate.
