Can NIR Replace Kjeldahl, Soxhlet, and Karl Fischer? AOAC Methods vs. NIR Can NIR replace Kjeldahl, Soxhlet, and Karl Fischer? We compare speed, accuracy, and cost so food and feed labs know exactly when NIR wins. <p>A grain elevator running 200 Kjeldahl digestions a week during harvest — two technicians, nothing else on their plates — can return that same protein result with a single NIR scan in 30 seconds. I've seen that exact situation at a mid-sized elevator in the Midwest, and the math is hard to argue with. But the question isn't just whether NIR is fast enough. It's where NIR genuinely fits into your workflow and where you still need wet chemistry behind it.</p> <p>The comparison between NIR and traditional methods comes down to three factors: speed, accuracy, and cost.</p> <p>NIR can analyze moisture, protein, and fat in under 30 seconds. Kjeldahl, Soxhlet, and Karl Fischer each take 45 minutes or more — and that's before you factor in reagent prep and cleanup.</p> <h2>How Does NIR Compare to Kjeldahl, Soxhlet, and Karl Fischer?</h2> <h2>When to Use NIR Over Traditional Methods</h2> ← Back to NIR Spectroscopy Blog