Laboratory & Chemical
Long-neck borosilicate 3.3 Kjeldahl flasks, 30 ml to 1 L, for sulfuric acid digestion in nitrogen and protein determination.
Specification
Product Knowledge
Background, typical uses and selection points for this product. We can send model drawings, technical data and samples to support your evaluation.
The Kjeldahl flask is made for the Kjeldahl method, the classic way to measure the nitrogen content of a sample and, from it, protein. The sample is boiled in concentrated sulfuric acid with a catalyst until it is fully digested, a hot, fuming step the flask has to withstand run after run.
Its long neck works as an air condenser, letting acid vapor condense and run back into the bulb so the digestion doesn’t boil dry, while keeping fumes away from the operator.
Kjeldahl flasks are used for nitrogen determination and the protein results derived from it in food and feed testing, agricultural and soil analysis, fertilizer analysis and total Kjeldahl nitrogen (TKN) testing of water and wastewater. Brewing and dairy labs use them for protein control, and QC, contract and research labs run them in banks on multi-place digestion racks. Teaching labs also use them to demonstrate classic wet-chemistry methods.
Each flask has a round borosilicate 3.3 bulb and a long, tapering neck, either plain or finished with a ground joint to connect to digestion and distillation units. The round bulb heats evenly and resists the thermal stress of acid digestion, and the neck length gives room for vapor to condense. Capacities from 30 ml to 1 L match common sample sizes and rack formats.
Digestion uses hot concentrated sulfuric acid, so work in a fume hood with full protective equipment, on a digestion rack that holds the flask at an angle. Heat gradually to avoid bumping and foaming up the neck, and never let the flask boil dry. Let it cool before diluting. Inspect each flask for scratches and cracks before every digestion and retire any damaged pieces.
We blow the bulb and draw the long neck from borosilicate 3.3, then anneal each flask for repeated high-temperature digestion. Wall evenness and neck geometry are the key production checks. Options include plain or jointed necks, neck lengths and diameters to suit your digestion block or rack, and packing in counts for lab supply. Send us your capacity and rack model and we’ll match the flask.
Customization
We specify the container, closure, decoration and transit packing as one package, so every part fits and arrives ready for your filling line.
Choose from standard sizes or request a custom capacity. We supply drawings with tolerances, label panel dimensions and nominal and brimful capacity.
We match caps, liners, pumps, droppers and stoppers to the neck finish and check the seal against your contents and filling process.
Flint, amber and colored glass, with frosting, spray coating, screen printing, hot stamping or labels. Material documentation is available on request.
Partitioned cartons, layer pads or bulk pallets, with shipping marks and pallet patterns planned for your route and warehouse.
Applications
Typical markets and uses. Tell us your contents, filling process and storage conditions and we will recommend the right model and components.
We confirm availability of the standard model, and review any changes to size, color, decoration or tooling for feasibility and lead time.
We send samples and specification sheets so you can check dimensions, component fit and finish before you place the order.
Your quotation covers packing design, shipping route, Incoterms and export documents, so landed cost is clear from the start.
Bulk Quote
Tell us the quantity, specifications and destination. We will reply with pricing, lead time, sample options and technical data for your chosen model.