Radioisotopes are used in the following techniques, except: Lok Sewa Aayog 2079

# Radioisotopes are used in the following techniques, except:

(A) Mass spectroscopy 

(B) RIA

(C) ELISA 

(D) Sequencing of nucleic acid

The correct answer is C. ELISA.

Radioisotopes were commonly used in ELISA (Enzyme-Linked Immunosorbent Assay) in the past, but they are no longer commonly used due to safety concerns and advances in technology.

In the past, radioactive isotopes such as iodine-125 and tritium were used to label antibodies or antigens in ELISA. These isotopes emit radiation that can be detected and measured to quantify the amount of labeled molecule in a sample. However, the use of radioisotopes poses risks to laboratory personnel and the environment due to the potential for radiation exposure.

Today, non-radioactive labeling methods such as fluorescent dyes or enzymes are more commonly used in ELISA. These methods are safer and more convenient, and they can provide similar sensitivity and specificity as radioisotope-based assays.