TOCWaterQualityChecker

TOC Water Quality Checker — Control of Total Organic Carbon in Water

ℹ️  Utility checks the quality of Purified Water (PW) and Water for Injection (WFI) according to USP <643> (TOC) and USP <645> (Conductivity):
     • Total Organic Carbon (TOC): ≤ 500 ppb (µg/L)
     • Conductivity: ≤ 1.3 µS/cm at 25°C (Stage 1)
     • System Suitability (SST): Standard response 85-115% of theoretical
     • Blank: ≤ 100 ppb (background control)

⚠️  CRITICAL: High TOC level (>500 ppb) indicates possible bacterial contamination, resin degradation, or organic leakage!
     Conductivity exceedance indicates insufficient demineralization.

Usage:
  TOCWaterQualityChecker.exe                            → demo mode (console output)
  TOCWaterQualityChecker.exe input.csv output.json      → evaluate your data

Input format:
BatchNumber,WaterType,TOC_ppb,Conductivity_uS_cm,Temperature_C,ResponseStandard_ppb,BlankResponse_ppb

Example:
  WFI-2026-LOOP-001,WFI,120.0,0.9,25.0,480.0,50.0

— WHY IS THIS NEEDED?
Water is the most used component in pharmaceutical manufacturing.
TOC control replaces the obsolete "Oxidizable Substances" test and is a more sensitive indicator of organic contamination.
Conductivity controls the presence of ionic impurities. These two parameters are key for water release into production.

⚠️  CRITICAL:
• TOC ≤ 500 ppb — strict limit for PW and WFI worldwide (USP, EP, JP).
• Conductivity depends on temperature. At 25°C limit is 1.3 µS/cm. For other temperatures, USP <645> tables are used.
• System Suitability (SST) must be performed daily or before a series of measurements using sucrose or benzoquinone standard.
• High background (Blank) makes measurements unreliable.

Key features:
• Simultaneous check of TOC and Conductivity
• System Suitability (SST) control
• Temperature consideration for conductivity interpretation
• Generation of reports for Engineering and QC departments, and LIMS LabWare
• Compliance with USP <643>, USP <645>, Ph. Eur. 2.2.44

Critical parameters:
• TOC: ≤ 500 ppb
• Conductivity: ≤ 1.3 µS/cm (at 25°C)
• Standard Response (SST): 85-115%
• Blank: ≤ 100 ppb

💡 Usage tips:
1. Sampling: Use dedicated TOC taps, flushing the system with water for 2-5 minutes beforehand.
2. Bubbles: Avoid air bubbles in the instrument cell, as CO₂ from air affects conductivity and TOC.
3. Calibration: Calibrate the instrument with sucrose standard (500 ppb C) regularly.
4. Interpretation: If TOC is normal but conductivity is high — problem with ion exchange resins or RO. If vice versa — problem with biofilm or organics.
5. Storage: TOC samples cannot be stored long; analysis should be performed immediately or within 24 hours under refrigeration.

⚠️ Note: USP allows testing in three stages (Stage 1, 2, 3). This utility focuses on Stage 1 (online or lab analysis without complex temperature compensation tables), which is the most common scenario for rapid control.