BIOANALYTICAL SYSTEMS LC-4B Amperometric Detector

Circa Mid 1980's to Mid 1990's (ESTIMATED)

A specialized electrochemical instrument designed for Liquid Chromatography/Electrochemistry (LCEC). It is utilized to detect redox-active species with high sensitivity and selectivity. This unit is typically used in conjunction with an electrochemical detection suite, and is only utilized as the controller/processor.

Use Cases:

• Pharmaceutical & Biotech: Detection of drug metabolites, thiols, and carbohydrates.

• Clinical Research: Analyzing neurotransmitters like catecholamines and other clinical biomarkers.

• Environmental Analysis: Measuring reactive oxygen (ROS) and nitrogen species (RNS) or phenols in aqueous samples.

• Academic Research: A standard instrument in university laboratories for electrochemical studies and teaching.

Typical Additional Hardware:

Electrochemical Flow Cell:

This is the housing where your mobile phase meets the electrodes. A complete flow cell consists of two main parts:

• Auxiliary Electrode Block: Typically made of stainless steel, it serves as the counter electrode and provides the fluid inlet/outlet ports.

• Cell Kit: Includes the specific working and reference electrodes required for your analysis.

The Three-Electrode System:

• Working Electrode: The active surface (e.g., Glassy Carbon, Gold, or Platinum) where oxidation or reduction happens.

• Reference Electrode: Provides a stable baseline potential (commonly Ag/AgCl or Saturated Calomel/SCE).

• Auxiliary (Counter) Electrode: Completes the circuit, often integrated into the cell block.

Gaskets:

Thin plastic sheets (usually 25–100 µm) placed between the cell block and working electrode to define the "thin-layer" flow volume.

Historical Significance:

The LC-4B was part of the "new generation" of electrochemical detectors that moved LCEC from specialized research into routine laboratory use. It helped establish subpicogram detection limits as a practical reality, enabling the quantification of trace analytes that were previously invisible to standard UV-Vis detectors. Its rugged design and precise control over potential and current ranges set the standard for analog-controlled electrochemical detection before the shift toward fully software-integrated systems.

(H-8.5cm x W-28cm x D-23cm)