For Research and Development (R&D) Use Only — Not for diagnostic, clinical, human therapeutic, or veterinary use.
0.22 µm Hydrophobic-Filtered · Ready-to-Use 0.5X
Chloride Ionic Strength Adjuster [0.5X]
Also referenced as Chloride ISAB (Ionic Strength Adjustment Buffer), Chloride ISA, or Chloride Background Electrolyte Solution
A ready-to-use potentiometric reagent engineered to equalize the ionic background of aqueous samples and calibration standards during chloride ion-selective electrode (Cl- ISE) measurements. This 0.5X working-strength formulation requires dilution prior to use. In addition to helping standardize ionic strength, the formulation may help reduce interference from certain anionic species in chloride ISE workflows, depending on R&D sample matrix and method conditions.
Filtered with a 0.22 µm hydrophobic filter for a clean, low-blank potentiometric reagent.
0.5X strength.
Supports EPA SW-846 Method 9212 and SMEWW 4500-Cl-.
Every lot of Chloride Ionic Strength Adjuster [0.5X] is filtered through a 0.22 µm hydrophobic membrane, delivering a particulate-reduced, low-blank reagent that minimizes extraneous background chloride and supports stable, reproducible electrode response. The product is supplied non-sterile in an amber glass bottle.
Scientific Rationale
Why an Ionic Strength Adjuster Is Required
Chloride ISEs do not measure free ion concentration directly — they respond to thermodynamic ion activity, which is governed by the total ionic composition of the solution. In real-world samples, ionic strength can vary significantly from sample to sample. These differences can shift the activity coefficient of chloride between samples and calibration standards, introducing systematic bias that is not fully addressed by electrode recalibration alone.
Adding a high-concentration ionic strength adjuster to all standards and samples saturates the total ionic background to a uniformly high level, making activity coefficients essentially identical across the entire sample set. This helps create a more consistent ionic background across the measurement set and supports accurate, reproducible chloride potentiometry in chloride ISE workflows, including EPA SW-846 Method 9212 and related laboratory methods.
EPA 9212
SW-846 potentiometric determination of chloride
SMEWW 4500-Cl-
Standard Methods for the Examination of Water & Wastewater
Composition
Formulation & Ingredient Roles
Ingredient
Role
Sodium bromate (NaBrO3)
Strong oxidant used to help suppress iodide, bromide, sulfide, and cyanide interference.
Nitric acid (HNO3), concentrated
Acidifies the matrix and helps maintain a stable measurement environment; may also help reduce hydroxide and carbonate effects.
Ultrapure Water
Low-background solvent used to minimize extraneous chloride contamination.
Laboratory Note: A sodium bromate and concentrated nitric acid buffer is documented for reducing bromide, iodide, sulfide, and small cyanide interferences in chloride ion-selective electrode measurements
Recommended Usage Protocol
Standard ISA Addition & Measurement
4 mL : 100 mL
Add 4 mL of this reagent per 100 mL of each calibration standard and sample before ISE measurement.
Apply to all solutions uniformly — including the blank, calibration standards (serial decade series: e.g., 1, 10, 100, 1,000 ppm Cl-), and unknown samples. Stir all solutions at a consistent, moderate rate during measurement to maintain a stable liquid junction potential and reproducible electrode response.
Compatible ISE Measurement Workflows
METHOD 1
Direct Measurement (Calibration Curve)
Standard approach for routine sample batches with consistent matrix.
METHOD 2
Standard Addition
Preferred for complex or variable-matrix samples; minimizes matrix-effect bias.
METHOD 3
Analyte Addition (AA) / Sample Addition
Useful when sample volume is limited or electrode behavior is slightly non-Nernstian in the sample matrix.
TIP
Uniform Treatment
Treat blank, standards, and samples identically for the most reproducible activity coefficients.
Applications
Research Applications
Environmental & Water Science
Stormwater runoff chloride monitoring — road salt (NaCl, CaCl2) contamination studies for R&D.
Soil extract chloride analysis for agricultural salinity profiling and remediation research.
Industrial process water and other complex aqueous matrices used in research studies.
Life Science & Biochemical Research
Cell culture media and buffer verification — chloride ion concentration QC for physiological buffer formulation (PBS, HBSS, Ringer's solution, DMEM).
Tissue extract chloride measurement (animal, plant, fish tissue) following wet-ashing or acid digestion.
Fermentation and process stream chloride monitoring in research settings.
Food Science & Nutritional Analysis
Chloride analysis in food and beverage research and formulation studies.
Cheese, bread dough, fermentation brine, and cured product chloride profiling.
Analytical Method Development & Validation
Establishing linear dynamic range, electrode slope verification, detection limit, and precision/reproducibility for new chloride ISE methods.
ISE electrode conditioning and stabilization of new or regenerated AgCl/Ag2S sensors prior to analytical runs.
Proficiency testing and inter-laboratory comparison sample preparation.
Corrosion science: precise chloride threshold determination for pitting corrosion initiation studies in materials research.
Related Literature
Chloride ISE Methodology & Applications
The peer-reviewed references below (indexed in PubMed) describe the analytical methodology, ionic strength adjustment principles, and sample-preparation context underlying chloride ion-selective electrode measurements. They are provided as background on the technique and its applications and do not report on this specific product.
Sekerka I, Lechner JF. Ion selective electrode for determination of chloride ion in biological materials, food products, soils and waste water. J Assoc Off Anal Chem. 1978 Nov;61(6):1493–1495. PMID: 730656
Cerklewski FL, Ridlington JW. Chloride determination in foods with ion-selective electrode after isolation as hydrogen chloride. J Assoc Off Anal Chem. 1987 Sep-Oct;70(5):924–926. PMID: 3680135
Lindner E, Pendley BD. A tutorial on the application of ion-selective electrode potentiometry: an analytical method with unique qualities, unexplored opportunities and potential pitfalls. Anal Chim Acta. 2013 Jan 31;762:1–13. doi: 10.1016/j.aca.2012.11.022. PMID: 23327940
Pietrzak K, Morawska K, Malinowski S, Wardak C. Chloride ion-selective electrode with solid-contact based on polyaniline nanofibers and multiwalled carbon nanotubes nanocomposite. Membranes (Basel). 2022 Nov 16;12(11):1150. doi: 10.3390/membranes12111150. PMID: 36422143
Safety & Handling
Laboratory Personnel Precautions
Corrosive, Strongly Oxidizing Acid Solution
Contains concentrated nitric acid and sodium bromate — classified as a corrosive, strongly oxidizing acid solution (UN 1826 / UN 1494 analogue, Oxidizer Class 5.1).
Handle exclusively in a chemical fume hood; risk of bromine vapor (Br2) generation during dispensing.
Wear chemical-resistant gloves (nitrile or neoprene), splash-rated safety goggles, and an acid-resistant lab coat.
Do not use with cyanide-containing samples unless a formal risk assessment and appropriate safety controls are in place.
Do not store with reducing agents, organic solvents, or flammables.
Neutralize waste with sodium bicarbonate before disposal per institutional EHS hazardous waste protocols for oxidizing acids.
Store sealed in the original amber glass bottle; do not freeze; avoid temperatures above 30°C.
Frequently Asked Questions
Common Questions
No. This is a 0.5X working-strength formulation that requires no further dilution prior to use. Add 2 mL of the reagent per 100 mL of each calibration standard and unknown sample before ISE measurement.
Chloride ISEs respond to thermodynamic ion activity, not free ion concentration, and activity depends on the total ionic composition of the solution. Because ionic strength varies between samples, the chloride activity coefficient can shift and introduce systematic bias. Adding a high-concentration ISA to all standards and samples saturates the ionic background to a uniformly high level, making activity coefficients essentially identical across the sample set.
It supports the foundational ionic strength adjustment step used in recognized chloride potentiometry methods, including EPA SW-846 Method 9212 and SMEWW 4500-Cl-. It is compatible with Direct Measurement (calibration curve), Standard/Known Addition (KA), and Analate Addition (AA) workflows.
The reagent is non-sterile and is filtered with a 0.22 µm hydrophobic filter. This produces a clean, low-blank reagent that minimizes extraneous background chloride. It is supplied in an amber glass bottle.
Store in a cool, dry area, protected from direct sunlight, tightly closed in the amber glass bottle. Do not freeze and avoid temperatures above 30°C. Unopened shelf life is 18 months. The product ships at room temperature.
Manufacturing & Compliance
Quality & Origin
ISO 13485 & CE
Manufactured under ISO 13485-certified and CE-approved facilities (Suppliers of Diagnocine Precision).
QA & Final Testing
All final packaging, quality assurance, and testing performed at the Diagnocine R&D and Quality Testing Center.
Assembled in the USA
Customization and assembly completed at Diagnocine Precision in Totowa, New Jersey, USA.
For Research and Development (R&D) Use Only. Not intended for diagnostic, clinical, human therapeutic, or veterinary use. This product is manufactured under ISO 13485-certified and CE-approved facilities (Suppliers of Diagnocine Precision). All final packaging, quality assurance, and testing are done at the Diagnocine R&D and Quality Testing Center. All specific customization requests and assembly were accomplished at Diagnocine Precision in Totowa, New Jersey, USA.
