User Guide
Module 1: General Description
1.1 Introduction to the SFRI ISE 4000
The SFRI ISE 4000 is a benchtop analyzer designed to measure key electrolytes in human serum, plasma, and urine samples. It provides precise results for:
Sodium (Na+)
Potassium (K+)
Chloride (Cl-)
Ionized Calcium (iCa)
pH
Total Carbon Dioxide (TCO2) - calculated parameter
1.2 Main Technology and Theory: Ion-Selective Electrodes (ISE)
The core technology used in this analyzer is Ion-Selective Electrode (ISE) Potentiometry.
Theory: Each measuring electrode (Na, K, Cl, Ca, pH) contains a special membrane that is sensitive to a specific ion in the sample solution.
How it Works: When the sample comes into contact with the electrode membrane, a potential (voltage) difference is created between the sample and the inside of the electrode. This voltage is measured against a stable Reference Electrode.
The Nernst Equation: The measured voltage is proportional to the logarithm of the ion's concentration in the sample. The analyzer uses this principle, along with calibration values from known standards (Std A & Std B), to calculate and report the ion concentration in the sample.
Key Components: The system consists of a measuring half-cell (the specific ion electrode) and a reference half-cell, completing the electrical circuit.
Module 2: Pre-Learning Course (For Installation, Repair & Maintenance)
2.1 Key System Components & Their Functions
Understanding the components is crucial for troubleshooting.
| Component | Function |
|---|---|
| Electrode Assembly | The core measuring unit. Contains individual electrodes for Na, K, Cl, Ca, pH, and the Reference electrode. |
| Peristaltic Pump | Creates suction to aspirate samples, standards, and cleaning solutions through the entire fluidic system. |
| Liquid Distribution Valve | A motorized valve that switches the fluid path between aspirating Standard A, Standard B, or the sample. |
| Sample Probe & Lifting Unit | Aspirates the sample from the cup and moves up/down between the sample position and wash block. |
| Wash Block | Cleans the external surface of the sample probe between samples to prevent carry-over contamination. |
| Liquid Positioner (Optical Coupler) | An optical sensor that detects the presence and position of the liquid segment in the tubing to ensure correct aspiration volume and detect bubbles. |
| RS-232 Interface | Allows for data transfer to a Laboratory Information System (LIS) or host computer. |
2.2 Critical Precautionary Measures
SAFETY FIRST! Always follow these guidelines before any service operation.
Electrical Safety: Always disconnect the instrument from the mains power supply before opening any panels or touching internal components.
Biohazard Safety: Samples can contain pathogens. Treat all waste (tubes, reagents, consumables) as biohazardous material and dispose of it according to your lab's safety protocols. Always wear appropriate PPE (gloves, lab coat, safety glasses).
Chemical Safety: Reagents and cleaning solutions can be irritants to the skin, eyes, and respiratory system. Handle them with care in a well-ventilated area. In case of contact, rinse immediately with plenty of water and seek medical attention if necessary.
Electrode & Component Handling:
Electrodes are fragile and expensive. Handle them with care.
Do not touch the sensitive membrane tips.
Never let electrodes dry out.
Keep the serial number labels on electrodes intact for warranty purposes.
Grounding: Ensure the instrument is properly grounded. Poor grounding is a common cause of unstable results, especially for Na+.
2.3 Environmental & Installation Precautions
Before installation, ensure the environment meets these requirements:
Platform: Stable, solid, and free from vibrations.
Environment: Free from excessive dust, corrosive gases, direct sunlight, heat sources, and strong electrical interference.
Ambient Conditions: Temperature 15–32°C, Relative Humidity <85%.
Power Supply: AC 220V/110V ±10%, 50/60 Hz. A power stabilizer is recommended if the line voltage is unstable.
Samples: Use only heparinized serum or plasma (exclusively Lithium Heparin). For urine, specific dilution protocols must be followed.
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