An automatic photometric method with high precision by gradually diluting a sample.

Area of Science:

• Analytical Chemistry
• Spectrophotometry

Background:

• Traditional photometric methods can suffer from precision limitations.
• Optimizing sample-reagent mixing is crucial for accurate spectrophotometric analysis.

Purpose of the Study:

• To develop an automatic photometric method for enhanced measurement precision.
• To minimize sample and reagent consumption while maximizing sampling rate.

Main Methods:

• Utilizes a rotary valve for precise injection of small sample volumes.
• Employs a syringe piston pump for controlled reagent delivery into a glass reaction cell.
• Achieves optimal absorbance (0.434) for lowest relative concentration error.

Main Results:

• Demonstrates uniformly high precision with relative standard deviations below 0.4% for cobalt determination (0.21-1.43 g L⁻¹).
• Achieves a high sampling rate of 30 samples per hour.
• Requires minimal sample and reagent volumes.

Conclusions:

• The proposed automatic photometric method offers a robust and efficient approach for precise chemical analysis.
• The method is characterized by ease of calibration and minimal equipment constraints.
• It is particularly effective for trace element determination, such as cobalt.