Ektachem

In 1978, Kodak were the first to introduce the multilayer film technique to the laboratory of the clinical pathologist and clinical chemist. This innovation had been decisively promoted by the development of the instant-image camera for space travel. 

Approximately 10-11 al of the sample or specimen to be assayed (serum or plasma, and for some chemistries urine or cerebrospinal fluid) are applied to the reagent carrier slide. The specimen will diffuse into the slide within a short time, where it reacts with a reagent that is present in a gelatine or agarose matrix. The dye that forms can be measured reflectometrically. The electrolytes (sodium, potassium, chloride and carbon dioxide) are assayed by means of single use ion-selective electrodes. 

The lowermost, last layer is the carrier layer made from a transparent polyester plastic (e.g. polyethylene terephthalate). Reflectometric measurement can be effected from this side and through this layer. 

All the layers are stratified on top of each other, cross-sectioned and embedded in a plastic mantle casing. The casing bears a visually and machine-readable coding of the slide (only Ektachem DT-60). 

Storage, changes taking place in the gelatine matrix (reagent layer) will render the slides unusable. 

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SYNCHRON CX3 Kodak EKTACHEM 300 max 600 26 10, II 37 R Beckman Hquid cahbrators and controls dry chemistry sHdes,... 

Figure 6.4 Cross-section through a dry reagent slide for use in the Vitros Chemistry System, previously known as the Kodak Ektachem analyser. A range of slides, which vary in the nature, number and composition of the layers, is available for a variety of analytes in blood serum. The sample (approximately 10 /d) is applied to the spreading layer and reactions take place as it permeates through the various layers. Detection is by reflectance photometry.

Bioanalyzer can be considered another version of commercial biosensors for off-line analysis. It was developed to have capabilities of complete analysis, short response time, specificity, and sensitivity that allows a quick clinical test. Abbott Vision, Boehringer-Mannheim Reflectron, and Kodak Ektachem DT60 (IBI Biolyzer is the new name) are used for cholesterol measurement in doctors offices. Bioanalyzer consists of biological and transducing component that are not physically connected. The uniqueness of this separation provides the versatility of analysis, i.e., use of disposable and different biological component for multi-components measurements. In authors laboratory, Kodak Ektachem DT60 was used successfully to determine cholesterol in some food matrices as well as in off-line process control. The analysis time was only 10 minutes compared to 1-2 days for the GC and HPLC methods. Complicated... 

Fig. 10. The cross section and chemistry of Eastman Kodak s Ektachem slide for serum creatinine determination.

Fig. 11. The cross sections and chemistries of (a) Seralyzer strip (Miles Diagnostics, Inc.) for serum AST determination and (b) Eastman Kodak s Ektachem slide for scrum ALT determination.

Seralyzer products package inserts, Miles Diagnostics. Kodak Ektachem Products News, Vol. 2, 1983. 

Ektachem produtts package inserts, Eastman Kodak. 

Artifactual hypoglycemia occurred in patients taking G-CSF when blood glucose was analysed on the Ektachem 700 analyser (SEDA-20, 339). 

Fuji evolved their system on a multilayer film technique basis. The primary goal has always been the determination of components of the blood without requiring external separation of serum or plasma (i.e. a centrifuge). Hence, it was necessary to develop a layer that would retain the coarse corpuscular blood components (erythrocytes, leukocytes etc.). The principles of the construction of the slides and the method of measurement are in accordance with the instructions that have been given for the use of Kodak instruments (see p. Ektachem system). The instrument is not available in Europe or on the American continent. It has also not yet been presented at exhibitions or congresses. So far, only the slides (reagent carriers) for the measurement of glucose and urea have been described in detail (D1-D6). 

Fig. 12. Dependence on the volume of sample as illustrated by glucose determination with the Ektachem.

The reflectometric evaluation procedure of the Ektachem system differs considerably from that of other dry chemistry systems. Ulbricht s sphere is not required in this reflectometric measurement. Measurement is effected from the underside of the slides. The arrangement of the measurement makes it possible to eliminate interfering substances that can influence the reflectometric measurement signal by their colour only. 

Fig. 14. Representation of a slide for the assay of electrolytes by the Ektachem system.

The slide of the Ektachem analyzer is used to measure the activity of the selected ion in serum water or plasma water. This applies to all potentiometric methods where the sample is not diluted. 

Ektachem DT-60 II (Fig. 15) was developed for the small laboratory of the practising physician and also for emergency analysis in a hospital laboratory. The slides for this system are packed individually and are used once only. Each slide bears a bar code marking and an inscription that can be read by the user. All the necessary reagents are already contained in the slide the user is only required to add 10 or 11 pi of patient sample. 

Ektachem DT-60 II is the basic instrument (further extensions are the DTE module for electrolytes and the DTSC module for enzymes) the course of the analysis is monitored from the Ektachem DT-6011, the dialogue with the user is effected via a keyboard and display and the result is computed and printed out. The user selects the slide required for the desired analysis, removes it from the packing and inserts it into the sample receiver unit. The undiluted serum is applied to the slide by means of an automatic pipette (Fig. 16). Pipetting of the sample is monitored via an optical detector. Subsequently, the time cycle for the period of incubation and measurement is started. Incubation for 5 minutes is effected at 37°C in the incubator to which the slide has been transported automatically. 

Fig. 16. Automatic pipette of the Ektachem DT-60 II system with pipette tips.

Kodak were the first to introduce a fully mechanised analysis system, the Ektachem 400 (Fig. 19). The Ektachem 500 and the Ektachem 250 (Fig. 20) were developed for smaller laboratories in hospitals. However, only the Ektachem 700 (Fig. 21) will be described here. Fundamentally, the instruments are similar, but Ektachem 250 also enables immunorate assays. 

The Ektachem 700 analyzer has been constructed in such a manner that mechanical parts can be monitored by computer. This results in easy operation, maintenance and problem-free servidng. Colorimetric, potentiometric and kinetic measurements can be performed. All the steps required for the reaction take place in the slides. These enable a quantitative determination of constituents of serum or plasma samples and some constituents of urine or cerebrospinal fluid. The slides are stored in cartridges (Fig. 22) that are sealed in aluminium foil. Each slide can be used for only one assay and is ejected directly after the measurement. 

Fig. 23. Schematic representation of the internal components of the Ektachem 700.1 slide storage I, 2 slide delivery, 3 slide storage II, 4 sample dosage unit, 5 reference solution dosage unit, 6 incubator for kinetic measurements, 7 reflectometer for kinetic measurements, 8 diskette drives, 9 reflectometer for colorimetric measurements, 10 incubator for colorimetric measurements, 11 slide rotor, 12 incubator for electrolyte slides, 13 electrometer, 14 sample rotor.

Ektachem 700 can be used as a selective and a batch instrument. Up to 540 analyses per hour can be performed. Samples from emergency cases can be inserted at any time the stored program steps of the other samples are preserved in storage. The computer can store data for a total of 800 samples. This allows the user to program assays of samples to be analysed at a later date. 

Fig. 24. KineticaDy measuring reflectometer in the Ektachem. 1 stepping motor, 2 lens system, 3 filter rotor, 4 lens system (collimator), 5 slide in the incubator, 6 filter, 7 aperture, 8 spheric mirror, 9 quartz halogen lamp, 10 objective lens system, 11 infrared filter, 12 mirror, 13 diaphragm, 14 photodetector.

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