Phthalate Buffer

Buffer Solution (pH 4.00) is a sterile, ready-to-use liquid reagent with a precisely known pH value of 4.00 at 25°C, specifically formulated for the calibration and quality control of pH meters, pH electrodes, and automated analyzers in clinical diagnostic and research laboratories. The solution is typically composed of 0.05M potassium hydrogen phthalate (KHC₈H₄O₄) as the active buffering agent, purified water (>98%), and a preservative to maintain solution integrity.

For the clinical laboratory scientist and medical technologist,Buffer Solution (pH 4.00) serves as the acidic calibration standard for two-point or three-point pH meter calibration (typically in conjunction with pH 6.86 and pH 9.18 buffers), ensuring accurate pH measurement of biological specimens including blood, urine, cerebrospinal fluid, and diagnostic reagents. The solution is classified as a Class I Medical Device (FDA Product Code JCC – General Purpose Reagent) and is 510(K) exempt, with traceability to NIST standards under ISO 17025 accreditation. Each batch is accompanied by a certificate of analysis detailing lot-specific pH value, measurement uncertainty, and expiration date, supporting GLP compliance for regulatory audits.

For the patient undergoing diagnostic testing for metabolic acidosis, diabetic ketoacidosis, renal tubular disorders, or other acid-base disturbances, accurate pH measurement of biological fluids—verified through proper calibration with certified pH 4.00 buffer—ensures reliable test results that guide appropriate treatment decisions across clinical chemistry, blood gas analysis, urinalysis, and pharmaceutical quality control applications. Available in various packaging formats including 30 mL sachets, 100 mL, 500 mL, and 1 L bottles, with color-coded red options for easy identification.