Behr STI Manual Titration Workstation for Kjeldahl Nitrogen Determination

Overview

The Behr STI Manual Titration Workstation is a precision-engineered component of the complete Kjeldahl nitrogen determination system, designed to support standardized wet-chemical quantification of organic nitrogen in diverse sample matrices—including foodstuffs, agricultural products, feedstuffs, environmental digests, and pharmaceutical raw materials. As a dedicated manual titration module, the STI integrates seamlessly with Behr’s Kjeldahl distillation units to deliver traceable, GLP-compliant nitrogen analysis in accordance with internationally recognized methodologies such as ISO 8968-1, AOAC 984.27, ASTM D1122, and USP . The system operates on the classical Kjeldahl principle: after acid digestion and alkaline distillation, liberated ammonia is captured in boric acid solution and quantified via standardized acid titration. The STI workstation ensures operator-independent endpoint detection through optical optimization—eliminating subjective interpretation bias while maintaining full compliance with manual titration protocols required for method validation and regulatory audits.

Key Features

• Optically optimized titration environment featuring a neutral-gray background shield with angled side wings to eliminate ambient light interference during endpoint observation.
• Precision-machined conical flask holder ensuring consistent flask positioning and vertical alignment of the burette tip relative to the meniscus—critical for reproducible endpoint discrimination.
• Digital-display burette with fine-adjustment stopcock and ergonomic grip, calibrated per ISO 385 and traceable to national metrology institutes.
• Integrated magnetic stirrer with variable speed control (0–1200 rpm), delivering uniform mixing without splashing or vortex-induced error in low-volume boric acid traps.
• Modular design enabling rapid integration with Behr Kjeldahl distillation modules (e.g., K-370/K-375) via standardized condensate delivery tubing and drip-sensor interface.
• Compact footprint (33 × 20 × 60 cm) and lightweight construction (~3.5 kg) facilitate benchtop deployment in QC labs with space constraints or mobile analytical units.

Sample Compatibility & Compliance

The STI workstation supports all standard Kjeldahl-compatible sample types processed under validated digestion protocols—solid, semi-solid, and liquid matrices up to 5 g sample mass or 50 mL digest volume. It is routinely deployed in laboratories operating under ISO/IEC 17025, FDA 21 CFR Part 11 (when paired with compliant lab notebooks), and GMP/GLP frameworks where manual titration remains the reference method for nitrogen certification. Its mechanical design conforms to IEC 61010-1 safety standards for laboratory electrical equipment. All components are constructed from chemically resistant PTFE-coated stainless steel and borosilicate glass, ensuring long-term stability in acidic and alkaline environments typical of Kjeldahl workflows.

Software & Data Management

As a manual titration platform, the STI does not incorporate embedded software or digital data logging. However, it is fully compatible with external LIMS and ELN systems via structured manual entry templates aligned with ISO 17025 documentation requirements. Laboratories may integrate the STI into electronic record workflows using validated spreadsheet templates (e.g., Excel-based calculation sheets with audit-trail-enabled version control) or paper-based logbooks with dual-signature verification per GLP Annex 13. For facilities requiring full 21 CFR Part 11 compliance, the STI is commonly paired with third-party titration data capture tools—such as Mettler Toledo LabX or Thermo Fisher SampleManager—that support instrument-agnostic manual entry with electronic signatures, time-stamping, and change history tracking.

Applications

• Crude protein content determination in cereals, dairy powders, meat products, and plant-based alternatives per AOAC 981.10 and ISO 20483.
• Nitrogen balance studies in soil science and fertilizer efficacy trials under ISO 11261 and EPA Method 350.1.
• Regulatory testing of feed ingredients for compliance with EU Regulation (EC) No 1831/2003 and AAFCO nutrient profiles.
• Method transfer and reference analysis in contract testing labs performing cross-validation against automated Kjeldahl or Dumas instruments.
• Educational use in university chemistry and food science curricula emphasizing foundational wet-chemistry principles and measurement uncertainty concepts.

FAQ

Is the STI compatible with non-Behr distillation units?
Yes—provided the condensate delivery tube diameter (standard 6 mm OD) and drip rate (≤2 mL/min) meet Behr’s mechanical interface specifications. Adapters are available upon request.
Does the STI include a calibrated burette?
Yes—the integrated burette is factory-calibrated to Class A tolerances per ISO 385 and supplied with a calibration certificate traceable to PTB (Physikalisch-Technische Bundesanstalt).
Can the STI be used for non-Kjeldahl titrations?
While optimized for boric acid–HCl titration, its optical and mechanical design supports other visual endpoint titrations (e.g., chloride by Mohr method, acidity in oils), subject to user validation per ISO 8655-6.
What maintenance is required?
Routine cleaning of the glassware and PTFE surfaces with deionized water; annual verification of stirrer speed accuracy and burette graduation integrity using certified reference standards.
Is technical support available outside Germany?
Yes—authorized distributors provide local installation assistance, operator training, and metrological recalibration services aligned with ISO/IEC 17025-accredited calibration laboratories.