Lesson 2


                                        Spectrophotometer 2


Vocabulary warm-up : match the words on the left with their Czech equivalents:


1 wavelength                                                                                     a)
odečtení absorbance

2 light beam
b) propláchnout

3 measurement                                                                                 c)
další pipetování

4 absorbance reading                                                                      d) vlnová
délka

5 pathlength
e) světelný paprsek

6 life expectancy
            f) detekce sraženiny

7 pressure sensor                                                                               g)
délka dráhy (šířka kyvety)

8 clot detection                                                                                 h)
životnost

9 flush
    i) tlakový senzor

10 further pipetting                                                                           j)
měření


Read the text and fill in the gaps with the articles THE or ZERO ARTICLE:


For each cuvette slot, ___ (1) spectrophotometer measures ____ (2) light intensity at 12 different
wavelengths. The light beam from ____ (3) halogen lamp passes through ___ (4) cuvette and then into
a photodiode array where the measurements are made.

The spectrophotometer makes both ____ (5) absorbance and turbidimetric measurements (typically for
clinical chemistry and specific proteins).

The absorbance readings are linear in ___ (6) range of 0.0 to 2.0 absorbance with less than 1 %
deviation at a pathlength of 0.5 cm.

The measurement system uses blank positions on ___ (7) rotor to monitor the background signal for
the electronic adjustment of drift.

The measurements are taken without removing the cuvette from the analyser rotor.

The life expectancy of the halogen lamp is 800 hours. The system informs you when you need to
replace the lamp.

The spectrophotometer makes ___ (8) measurements at the following wavelengths:

340 nm * 480 nm * 552 nm * 652 nm

378 nm * 512 nm * 583 nm * 659 nm

409 nm * 520 nm * 629 nm * 800 nm


All wavelengths are measured at ____ (9) same time, but only one wavelength (for monochromatic
measurements) or two wavelengths (for ___ (10) bichromatic measurements) are used.


Clot detection

For each sample probe, one pressure sensor for clot detection is mounted at the rear of the
pipetting module. They detect clots during aspiration of samples, during the washing of probes, or
when initialising the system.

When a clot is detected, the probe is flushed, and a message is displayed. The run continues but no
further pipetting is done from the sample cup that led to clot detection or with the probe that is
blocked. No results are printed for the sample cup associated with the clot.

When an aspirated clot clogs the probe and the automatic washing steps cannot remove it, the system
stops sampling and goes into the standby mode as soon as all of the currently scheduled
measurements are finished.


Read the text on clot detection and decide if these statements are TRUE or FALSE:


1 The pressure sensor is located at the back of the pipetting module.

2 Clots can form only during aspiration of samples.

3 When the sensor detects a clot, the device sends a sound signal and stops working.

4 Clotted samples show no results.

5 The probe can work even if there is a clot.