Conc H2SO4, NaOH, HCl, mixed acids, and HF all impose strict wetted-parts constraints. Mismatching the material causes rapid corrosion and reduces meter life to months. This guide walks through chemical types.
Chemical Strong Acid / Alkali Density Meter Selection Guide
For strong-acid / strong-base media, density meter selection must start by solving the materials problem. This guide breaks recommendations down by chemical type.
Steps
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Concentrated H2SO4 (98%)
Recommended: PS7400 (PTFE-coated + titanium fork) or PS7110 (sapphire prism is conc-H2SO4 resistant). PS7110's advantage: no metal contact, avoiding any sulfuric-acid catalytic reaction. -
NaOH (32% / 48%)
Recommended: PS7400 (PTFE-coated + 316L base) or PS7100 (fiber-optic separated, controller in safe area). Note: high-concentration hot NaOH (> 50% + > 100°C) MUST use PS7100 or PS7110 — standard 316L stress-corrosion cracks. -
Hydrochloric acid (HCl)
HCl is strongly corrosive to most metals. Recommended: PS7100 (no wetted main body) or PS7110 (sapphire + PTFE connection). Do NOT use a standard 316L fork. -
Mixed acids (H2SO4 + HNO3 / HF + HNO3)
Two or three component concentrations needed — this is a flagship PS7100 spectroscopy use case. MLR multi-component modeling outputs each acid concentration in parallel. -
Hydrofluoric acid (HF)
HF attacks nearly all glass and metals — only PTFE / PFA / sapphire withstand it. Recommended: PS7100 (no wetted parts) or PS7110 (sapphire prism + PTFE flow cell). Semiconductor BOE buffered etchant commonly uses this approach. -
Chlor-alkali sodium hypochlorite (multi-component classic)
Simultaneous available chlorine + free NaOH is the signature PS7100 application. MLR R² > 0.99, reaction endpoint auto-detected, operators don't handle toxic samples.