Although this column discusses regulatory requirements and issues, it is important not to forget that the main reason for backing up your application and data is a business one. You'll install your software and then configure the system by defining items such as authorised users, user types, access control privileges, user-defined macros, libraries, and so forth. Imagine the problem if your computer hard disk fails and you have no effective backup. What happens next?   

You'll have to reinstall the base software from CD and then input all of the configuration data manually — assuming that you remember what each one was. Not a pleasant thought, is it? Furthermore, consider the data and electronic records that you have created since the original installation — how are you going to recreate these? The simple answer is that without backup records you cannot. 

Therefore, regardless of the regulations — if you are working in research, development or production — you need an effective backup procedure for business reasons alone. Not convinced yet? Take the example where a spectroscopy laboratory only works with paper. If a regulatory submission is needed and there are spectrometry data to be included you'll have to scan the paper into a format that can be included into the electronic regulatory submission. 

Any standard operating procedure usually has the following sections as a minimum: 					

Generation of documented evidence (to demonstrate that the procedure was followed)

Every company has their own way of writing SOPs and different formats, so we'll focus on the main sections and look at each of these in turn during this column.  

Remember that the procedure is a formal document with management and QA approvals required as well as document controls (pagination in the format of page 

, document identity, version controls, and so forth), although we will not discuss these aspects here. 

The purpose of the procedure should be described in a single sentence or paragraph. Typically, the purpose statement could be written as, "Documenting the procedure for the backup and recovery of the application and electronic records of spectrometer system X," or equivalent. There is no need to go into any more detail if your purpose sentence is simple and explicit. 			

The scope of the backup and recovery procedure can depend upon whether your spectrometer is a standalone or a networked system. If the system is a standalone one, then you — the lucky user — are responsible for everything. However, if it is a networked system then typically we're dealing with the IT department to back up the system on behalf of the laboratory. In the latter case we're crossing departmental boundaries with all of the communication issues that that entail. 

Similar to the purpose statement, there should be a simple scope statement to outline the SOP boundaries and identify what is in the procedure and what is outside of the procedure. Establishing the boundaries of the procedure is important at the beginning of the document to manage the expectations of any reader as to the details of the document.  

Let's now look at the detail of the procedure by considering who is involved and what they should be doing: the roles and responsibilities of all involved in the process. There are two main roles involved with backup and recovery in a networked environment in most organizations: 					

I'm assuming that either the spectrometer is networked or the system operates in a standalone mode and the records that are produced are transferred to a network drive for backup and recovery. End-users are responsible for backup and recovery because it is their system and their data. These facts often are overlooked when a backup schedule is developed. Responsibility often can be abrogated and a default schedule given that is not appropriate to the system or the data held on it. Users must be aware that this is their responsibility and that they are accountable, even though the work is carried out by a third party. Some of the user responsibilities: 

Define the type of backup required: full only, full and incremental or full and differential (as outlined in Part IX of this series)

Define the speed of any data or application recovery in the event of failure

The IT department will carry out the backup and recovery of data on behalf of the end users. The schedule for the backups will be worked out in discussions with the end users and this should be recorded in a service level agreement (SLA) that outlines the roles and responsibilities of all parties and the schedule. IT will also need to have a procedure that covers: 					

How to recover records and the  application

Defining the interface between the laboratory and the IT department

There is a third role that will be involved in the process: quality assurance. QA will be involved in authorizing the SOP as well as checking that any work described in the procedure has been carried out correctly via a periodic audit.  

Table I. Combined process flow and task description			

The procedure for performing a backup should be defined in sufficient detail to ensure that any trained person undertaking a backup can repeat the task. How this is to be achieved depends upon your company's approach to writing a procedure. This can be accomplished through one or a combination of the following ways: 					

From a personal viewpoint, I prefer a flow chart and text as this gives a better understanding of the procedure. At the simplest it can be a flow chart that outlines the main points in the procedure plus a textual description of each step. Figure 1 shows a high level procedural flow chart for a backup of a system.  

Figure 1. High level procedure for backup of a spectroscopy application and data.			

This process flow can be linked to the text by referring to the number in the individual stages of the process. A better approach is to link the two together in a table so that the process flow and work instructions side by side with little room for misinterpretation as shown in Table I. In this approach the process flow and the work instruction are easily and visually linked for easy of interpretation. If further required, any role involved in the process also can be added to the table as a separate column to clearly identify the role with the work instruction. 

The recovery process also needs to be documented in a similar way to the backup process has been described. Therefore if you use the text or process based approach for the backup this must be mirrored in this section for the recovery process. 							

Key in this section is to define what events trigger the recovery process? These can vary from the recovery of a single file to the recovery of a whole disk. In any event, the process for obtaining the latest tape or CD from the media store, loading it on the drive and then transferring the files to be recovered to the spectrometer database. There also needs to be a verification step to ensure that the file or files have been correctly copied back to the system.  

To ensure that there is evidence that the procedure has been followed a backup and recovery logs are required. For practical purposes we'll look at backup only as recovery is simply the mirror image of backup. At its simplest this is a record that each backup has been performed without error by looking at the log or file produced by the backup software after each backup. The person (user of IT depending if the system is standalone or networked) looks at the log file produced by the backup software to check if there are no problems recorded in it. If there are no issues, then the paper backup log is noted for June 10, 11, and 13. However if there is a problem as seen on June 12 with write errors on the tape; then the tape is replaced and the backup is repeated. This is one way to approach the issue of a failed backup.   

Table II. Example of a basic system backup log						

Another way, if documented in the procedure, is that the users may take the view that the backup can go for another 24 h before the backup is repeated. Here, the risks of not backing up immediately following a media failure must be balanced with the time taken out of the working day to ensure that records are preserved. This is your laboratory's judgement call, not mine. 

Whatever requirements are needed for the backup and recovery of a networked spectrometer system, they need to be incorporated in an SLA so that the IT department have a standard to work against. The SLA can also provide a standard or benchmark for QA to audit against, providing that the agreement has specific and measurable performance criteria.  			

The SLA with the internal or outsourced IT department should cover and document the following parameters as a minimum:  					

Definition of the software and records to be backed up and the frequency of each

The content of an SLA is outside of the scope of this discussion and the reader is referred to the book by McDowall (1) for further information. 

Articles

Columns

The author continues his discussion of the principles involved in the backup and recovery of electronic records. This installment looks at the written procedures associated with this process for a spectrometer operating in a regulated laboratory.

Focus on Quality: Validation of Spectrometry Software

The study of photophysical properties of heterocyclic organic molecules has achieved considerable importance recently because many of these molecules form an integral part of biologically important compounds and have various uses. Substituted 2-arylbenzothiazoles, although having industrial and commercial uses as fluorescence whitening agents (1), photoconducting materials (2), and as herbicides in agriculture, have not received much attention.			

				In the last few years, benzoxazoles and related heterocycles benzimidazoles and benzothiazoles were studied extensively for their antitumor, antiviral, and antibiotic properties as the new nonnucleoside topoisomerase I poisons, HIV-1 reverse transcriptase inhibitors, and potent DNA gyrase inhibitors (3–7).

The biochemical reactivity of a drug is a direct consequence of its electronic structure, which manifests itself in several ways. The most straightforward manifestation occurs in the electronic absorption spectra. This manifestation enables the detailed understanding of the forces that govern the electronic structure of the studied molecules. The following article presents a comparative investigation of the electronic absorption spectra of the studied benzazole, 2-phenyl benzazole, and 2-(4-aminophenyl)benzazole. .			

The studied compounds possess two positions that can accept protons, with a subsequent delocalization of the charge, (see Figure 1) and one or two sites that can donate protons to the solvent. Thus the spectral shifts observed depend upon the preferential interaction of the solvents with the solute molecule. The solvent effect thus needs to be investigated thoroughly and analyzed. 

 Figure 1. The studied compounds have two positions that can accept protons with a subsequent delocalization of the charge, and one or two sites that can donate protons to the solvent.

The spectra of large organic molecules usually are very difficult to interpret because most electronic transitions are observed as broad diffuse bands. Computer-deconvolution of these bands therefore is essential. However, theoretical computation of the spectra of the drugs under investigation is essential to get a quantitative understanding of the ground and excited state properties and their polarizabilities. This can be done efficiently either using semiempirical methods specially parameterized to reproduce experimental spectra, such as the ZINDO/S method, or by using the time-dependent density functional theory (TDDFT) method, which is the most widely applicable method nowadays (8–13).			

In the present study, the electronic absorption spectra of some benzazoles, 2-phenylbenzazoles, and 2-(4-aminophenyl)benzazoles were measured in different solvents and calculated theoretically at the TDDFT/B3LYP/6-31G** level of theory. Results are compared with those obtained by the semiempirical ZINDO/S method, which is designed and parameterized to reproduce experimental electronic spectra. Analysis of the charge density distributions and relative polarities of the ground and excited states will enable quantitative understanding of the observed solvent effects. 

The present study is in fact a part of a major project aimed at the development of a quantitative structure–activity relationship (QSAR) for the series of antitumor drugs under investigation. All structure-determining factors will be accounted for in the QSAR study. 			

All calculations were performed using the G98 (14) package of programs. The ground-state structures were optimized at the B3LYP (15)/6-31G** level. TDDFT and ZINDO/S were used to calculate the excitation energies and electronic spectra. The electron-density distributions of the molecular orbitals involved in the electronic transitions were mapped using the hyper chem.V

 software package, which operates in a Microsoft Windows environment. Computer deconvolution of the experimental spectra was performed using Mathcad 7.0 Plus (16) software. 			

 All solvents used in the present work were BDH spec quality, which were used without any further purification. 			

 All the studied compounds (APBO, APBT, APBI) were prepared and purified as reported in the literature (17) (see Figure 2). 

Figure 2. All the studied compounds (APBO, APBT, APBI) were prepared and purified as reported in the literature (17).			

 All absorption spectra reported in this work were measured using a JASCO UV-530 Spectrophotometer through the wavelength 2.48–7.44 eV using 1.0-cm cells. 

Electronic spectra of benzazole and 2-phenyl benzazole.

 It is interesting to examine the electronic spectral characteristics of benzazoles before we discuss that of the composite systems under investigation. Table I presents the experimental and theoretical spectra of benzimidazole (23), benzoxazole (20), and benzothiazole (22). In the case of benzoxazole, the first absorption band centered at ~3.42 eV is derived from the B

 benzene system, and shows its characteristic fine vibration structure. The moderate bathochromic shift and intensification relative to the benzene system at 3.16 eV is a normal result of weak conjugation of the heteroatoms with the phenyl ring. This broad band, which spans the region 3.47-3.1 eV, was attributed experimentally to one transition, the B

 system of the benzene moiety. 										

Theoretical calculation of the spectrum of benzoxazole, however, shows two main band systems in this region, the first centered at 3.56 eV with moderate to weak intensity and a much stronger transition centered at 3.16 eV. The first, S

 state composed of three main configurations: φ

 state centered at 3.16 eV, is composed of two main transitions: φφ

. It is interesting to note that these two configurations are the major components of S

 states involve transitions from the molecular orbital φ which is localized on the benzene ring. On the other hand, the delocalization of φ

 are transitions localized on the benzene ring perturbed to some extent by the heteroatom system. 

It should be noted that while ZINDO/S reproduced the experimental spectra fairly well, the TDDFT method reproduced the right order and origin of S

 although the correspondence between the computed and experimental transition energies is not satisfactory. The TDDFT computations underestimate the wavelength of all states by 0.37 eV. 			

Replacement of the O-heteroatom by NH does not introduce any appreciable changes in the extent of conjugation or polarization of the electronic spectra. Thus, the electronic absorption spectra of benzimidazole are very much similar to that of benzoxazole. Results of the present work confirm that the TDDFT approach underestimates the position of all transitions. The magnitude of this underestimation amounts to 0.37 eV, as in the case of benzoxazole. 

Four overlapping band systems are observed in the spectrum of benzothiazole at 3.65, 3.53, 3.12, and 2.68 eV. The ZINDO/S computation reproduced the experimental spectrum fairly well. Results are presented in Table I. The first (π, π*)

 state is a delocalized transition involving the whole π system. The involvement of the S-atom p

 orbitals in conjugation seems more pronounced in the case of benzothiazole than O- or NH conjugation.			

TDDFT/B3LYP/6-31G** computations of the spectrum of benzothiazole follow the same trend observed in the case of benzoxazole and benzimidazole in that they underestimate considerably the position of electronic transitions by ~0.42 eV. Moreover, the separation between S

, which is observed to be 0.41 eV and predicted by ZINDO/S to be 0.18 eV, is reduced appreciably in TDDFT calculation to 0.04 eV only. 

Table II presents a comparison between the experimentally observed and theoretically computed spectra of the 2-phenyl benzoxazoles studied in the present work as compared with benzoxazoles the phenyl derivatives show, as a general trend, considerable red shift and intensification of the first (π, π*)

 state. This would suggest extended conjugation over the entire molecular framework. In the case of 2-phenylbenzoxazole, the ZINDO/S calculated transition energy for the first (π, π*)

 state is in good agreement with the experimental value. Both methods assigned this state to HOMO–LUMO (highest occupied molecular orbital–lowest unoccupied molecular orbital) transition as a major configuration. This elaborates upon our assumption that this molecule enjoys considerable π–conjugation extended over the whole molecular framework. The same general agreement holds in the case of 2-phenylbenzothiazole where the ZINDO/S calculations agree well with the experimental transition energy for the first (π, π*)

 excited state and in its assignments to a major configuration involves a HOMO–LUMO transition. 			

It should be noted at this point that the first (π, π*)

 state in all the 2-phenylbenzazoles studied are much less polarized than that of the corresponding states in benzazoles. This would suggest that the TDDFT approach underestimates the position of highly polarized excited states. 

This underestimation decreases as the polarization of the excited state decreases. In the case of transitions that involve no charge transfer (CT) character, TDDFT predicts transition energies in the same quality as that predicted by ZINDO/S and are in good general agreement with the experimental spectra. 

The electronic spectra of 2-(4-aminophenyl)benzimidazole (APBI).

 Figure 3 presents the electronic absorption spectra of APBI in different solvents. The spectrum in ethanol shows four diffuse and broadband systems, centered at 3.97 eV, 3.6, 3.21, and 2.6 eV. The high extinction coefficient, and red shift of λ

 with increasing solvent polarity, confirm the π–π* nature of these transitions. The small blue shift observed in water relative to methanol or ethanol indicates that water is acting as a better hydrogen donor solvent to the ion pair of the amino group rather than a hydrogen acceptor. 

Figure 3. Electronic absorption spectra of (a) 2-(4 aminophenyl)benzimidazole, (b) 2-(4-aminophenyl)benzothiazole), and (c) 2-(4-aminophenyl)benzoxazole.			

The two normal band systems of benzimidazole molecule (3.45, 3.73, L

) are kept intact except that both are red shifted (3.97, 3.94, 3.6 eV, L

), whereas the third band system, which, in the case of benzimidazole, is observed in the 210 eV region with a considerable vibrational structure, appears in almost the same position in the case of APBI yet the detailed fine structure is lost. 

Table III presents a comparison between the experimental spectrum and that computed theoretically using ZINDO/S and TDDFT methods. The TDDFT theoretically computed spectra of APBI predicts three (π, π*) states at 300.6, 278.5, and 3.32 eV, while ZINDO/S predicts three (π, π*) states at 320.9, 292.9, and 285.5 eV. 

The first is a long wavelength transition at 320.9 eV, which is in excellent agreement with experimentally observed value (320 eV). This excited state is a (π, π*) and is a mixture of three main configurations: φ

. The HOMO–LUMO transition seems to dominate this state (~40%). This configuration is localized largely on the phenyl ring with a little contribution from the heterocyclic moity (see Figure 4). Therefore, this transition opposes the dipole moment vector and hence the S

 state is less polar than the ground state. This would suggest that the first (π, π*) excited state would show slight red shift upon increasing solvent polarity. 	

Figure 4. Representation of the charge density distributions of the frontier orbitals involved in ZINDO/S calculation for 2-(4-aminophenyl)benzimidazole.

 singlet state of APBI is predicted by TDDFT at 3.72 eV in a less satisfactory agreement with ZINDO/S and experimental spectra (3.97 eV). However, TDDFT agrees with ZINDO/S in the assignment of this band to a HOMO–LUMO transition as a dominating ~40% configurations and also agrees with the polarization changes predicted by ZINDO/S. This is in agreement with the conclusion drawn by Parac and Grime (18) that TDDFT the approach shows strongly size system dependent error for the low-lying π–π* excited states. In the present case, this error is an overestimation of the excitation energy of the first π–π* state amounts to 0.25 eV. 

The two normal band systems of APBI are observed at 3.45 and 3.37 eV (19) and predicted theoretically by ZINDO/S at 3.63 and 3.53 eV; TDDFT, on the other hand, predicts these two transitions at 278.5 and 269.97 in excellent agreement with the experiment. These bands correspond to S

In the case of ZINDO/S calculations, the second (π, π*) 1 excited state is a mixture of the φ

. The later configuration involves an intramolecular CT from the heterocyclic moiety into the phenyl ring, whereas the φ

 configuration is a transition localized on the phenyl ring. This contribution manifests itself as a perturbation only to the main configuration φ

. The third (π, π*) excited state is composed of a major configuration φ

. Both molecular orbitals are more or less delocalized over the entire molecule. Thus, the third state (S

) (π, π*) transition is a delocalized transition involving the entire molecule. S

 states are less polar than the first and the ground states, which explain the sensitivity of their positions to solvent polarity. 

Figure 5. Representation of the charge density distributions of the frontier orbitals involved in ZINDO/S calculation for 2-(4-aminophenyl)benzothiazole.

TDDFT/B3LYP/6-31G** computed spectrum is presented together with the experimental data in Table III. Careful inspection of the data presented in this table reveals the following: 					

The general features of the spectrum computed by TDDFT resembles those predicted by ZINDO/S calculations; it shows a long wavelength absorption at 3.72 eV and two short wavelength bands at 3.45 and 3.34 eV.

) is composed of a major configuration φ

φ, that corresponds to a HOMO–LUMO transition (

 excited state is a combination of two configurations, namely φ

 dominates to a large extent, which corresponds to HOMO–LUMO+1 (

The third (π, π*) excited state is a combination of φ

 configurations. The weight of the former is much greater (~40%). This configuration corresponds to HOMO-1–LUMO transition. Surprisingly, the S

 states always are much less polar than the ground state.

 transition exhibits a weak intensity as compared to that of the L

 state. Since the states are close in energy (L

 state is very often hidden under the more intense 

 band and therefore difficult to detect experimentally.

It is worth noting that TDDFT was superior to ZINDO/S in predicting the excitation energies of S

 Tables IV and V present the experimental and the theoretically computed spectra of APBT and APBO. The similarity of the spectra of APBT and APBO with their respective phenylbenzazole, the type of molecular orbital contributions, and its polarization indicate that the lowest energy transitions in these molecules are of the π–π* character and reflects the extended conjugation in these molecules. 

Figure 6. Representation of the charge density distribution of the frontier orbitals involved in ZINDO/S calculation for 2-(4-aminophenyl)benzoxazole.

The red shift in the longest wavelength band of (APBT or APBO) as compared to that of benzazole and 2-phenylbenzazole, can be explained by the charge transfer interaction of NH

 group with aromatic moiety. Figures 3b and 3c present the electronic absorption spectra of APBT (3b) and APBO (3c), in different solvents. 

Although the general features of these spectra do not differ much from those of the spectrum presented before for APBI, the observed bands in the spectra of APBT and APBO are red shifted and intensified as compared to those observed in the spectrum of APBI. In fact, the general features, peak position, and intensities of the spectrum of APBT resemble those of APBO to a striking extent. The theoretically computed spectra (TDDFT and ZINDO/S) of APBT and APBO are presented and compared with the experimental spectra in Tables IV and V, respectively. 

Table I. Theoretical and experimental spectral characteristics of the studied benzazoles.

The assumption made by Passarini (20) that the phenyl moiety in the studied composite compounds acts as the main chromphore is not entirely correct. The present molecular orbital calculations indicate clearly that the first (π, π*)

 excited state in the spectra of APBT and APBO is a delocalized state involves the entire molecular framework. These (π, π*)

 states are composed of a major configuration that involve the HOMO–LUMO transition. APBT show its first (π, π*)

 state at a longer wavelength than that of APBO. This (π, π*)

 state show red shift by increasing solvent polarity indicating that it is more polar than the ground state. 

Time-dependent density functional theory and ZINDO/S methods have been used to compute and analyze the electronic spectra of benzazoles, 2-phenylbenzazoles, and 2-(4-aminophenyl)benzazoles. The observed spectra of the studied antitumor drugs are diffuse and highly solvent-dependent. Spectral analysis of the charge density distributions and relative polarities of the ground and excited states have enabled understanding of the observed solvent effects.

Theoretical and Experimental Investigation of the Electronic Spectra of Antitumor Compounds

 is proud to present its annual review of products displayed at our industry's premier trade show, the Pittsburgh Conference. The 

 editorial staff spent a good portion of the show investigating and collecting information on exhibitors' offerings, and a sampling of those instruments appear below, including a brief product description and the company's name and Web address. We have made every effort to provide as comprehensive a listing as possible, but as in years past, we cannot claim to have made a complete record of every product shown at the conference. 

Designed by the US Naval Research Lab, the CP-1000 provides in situ determination of heavy and hazardous elements in soil by combining downhole cone penetrometer technology with an XRF sensor. Fully compliant to EPA Method 6200, the instrument's high sensitivity reportedly provides low detection limits for arsenic, barium, cadmium, chromium, lead, mercury, selenium, and silver. 

The VÃTEC-2000 is a two-dimensional X-ray detector for research applications in materials science. The instrument can achieve a 14 Ã14 cm active area with spatial resolution of 70 Äm and dynamic range of 108. With its real-time display and true photon counting capabilities, the VÃTEC-2000 is designed to improve data quality in demanding applications such as small-angle X-ray scattering (SAXS), thin-film investigations, and micro-XRD analysis. 

The Eagle III micro-XRF elemental analyzer uses capillary optics, CCD video imaging cameras, and a motorized xyz stage for nondestructive small-spot analysis correlated with video imaging. Features include simultaneous detection of elements ranging from sodium to uranium, and little or no sample preparation requirements. Typical applications include forensics, failure analysis, coating thicknessâcomposition measurement, quality control, and chemical imaging. 

The Niagara Rapid Rinse Accessory reportedly significantly shortens the analysis cycle time of an unattended ICP spectrometer run, and as a result, achieves higher productivity and faster sample turnaround times. The Niagara begins the rinsing of the nebulizer and spray chamber the instant a sample measurement is completed and continues to rinse until the next sample is ready. Thus the rinse is performed in the time that is usually wasted waiting for the sample and the rinse solutions to flow from the autosampler to the  nebulizer. 

- The Capricorn argon humidifier for ICP analyses is designed to be particularly useful when analyzing samples with high dissolved solids concentrations. It reportedly helps to prevent salt buildup inside the sample introduction system, allowing uninterrupted and maintenance-free operation. Features include plastic construction and a built-in diagnostic pressure gauge. 

The SINDIE-7039 Sulfur in Oil Analyzer has a measurement range of 0.4-3000 ppm, and uses the monochromatic wavelength dispersive X-ray fluorescence method. The instrument, which can be set up for remote diagnostics capability, can store as many as eight separate calibration curves, with six calibration points per curve.  

The ACTIVA ICP spectrometer features simultaneous analysis of all elements and background within a Wavelength Analytical View (WAV). Users can select any elemental wavelength from 160-800 nm, their choice of WAV, and advanced analysis modes. Features include a 0.64-m Czerny-Turner optical system combined with an Advanced Inverted Mode Operation (AIMO) CCD detector system, and ACTIVAnalyst software, which extends the instrument and analysis control of Analyst ICP software in a multitasking platform. 

QXi Micro XRF analyzers perform elemental analysis from chlorine to uranium, use collimated beams of 13â0.1 mm diameter with laser beam focusing, and are designed for testing small or nonhomogeneous samples. Applications range from the analysis of lead-free solders for electrons, circuit boards, and chip studies to precious metals, bronzes, and alloys. Featuring X-ray tube technology that reportedly eliminates radioactive isotopes, the bench-top instrument incorporates a Silicon-PiN Diode detector, and features an optional xyz stage for measurements during batch operations. 

- The Alpha Series of handheld analyzers provide on-the-spot elemental analysis from phosphorus to uranium. Featuring a removable handle that allows it to fit into tight spaces, the Alpha Series analyzers use high Si PiN diode detectors for eliminating radioactive isotopes. Typical applications span material identification for new product quality control and assurance, recycling of metals, and checking levels of impurities. 

Inorganic Ventures offers custom inorganic standards for AA, ICP, ICP-MS, and IC. Standards are made according to the manufacturer's expertise and user's specs. Each custom standard's Certificate of Analysis details NIST traceability, certified values, and trace impurities. 

The EX-Calibur is a liquid nitrogen-free bench-top EDXRF spectrometer with an integrated computer system. The 50-kV, 50-W spectrometer is designed to provide high-count throughputs and features improvements in PIN diode technology, resolution, and peak-to-background ratios. 

The Perl'X 3 is a fusion instrument that performs fully automated bead preparation for XRF analysis. The instrument is reportedly able to handle most minerals and can be used to fuse mineral samples into beads for typical XRF applications in various industries, including cement, industrial minerals, and nonferrous and ferrous metals. Features include an on-board microprocessor with a memory that stores up to 38 user programs. 

- The company has published a white paper describing how its X-ray diffraction (XRD) systems are designed to enable users in the pharmaceutical industry to meet the requirements of the FDA's 21 CFR Part 11 regulations. The paper, which is available on the company's Web site, provides guidance for both existing and new users of the company's XRD systems. 

- The MiniMill 2 is a grinding instrument that reportedly achieves fine grain sizes for XRF analysis. Based on the principle of planetary ball mills, the instrument's grinding bowl is available in sizes ranging from 80-500 mL. The mill delivers short grinding times by reportedly operating at speeds as high as 600 rpm, and features an electronic system with a timer and programmable reversing unit. Applications include ceramics, industrial minerals, plastics, and food. 

The Aerosalt High-Solids concentric nebulizer and a redesigned sub-boiling point still for acid purification are available. The company continues to manufacture replacement torches, spray chambers, nebulizers and injectors for ICP and ICP-MS instruments. All parts are made to OEM specifications and are intended for direct replacement of OEM parts. Additionally, the company now also offers the entire line of Elemental Scientific PFA and PolyPro concentric nebulizers. 

The ZSX Primus II is a 4-kW WDXRF spectrometer with a thin end-window tube  (30 Î¼m) and the analytical capability for Be-U. Features include "tube above" (inverted) optics and small spot and  mapping capabilities. 

PURE Plus high purity acids are designed for trace metal analyses. Users can choose between two grades of high purity acids for ICP-MS, ICP-AES, flame AA, and graphite furnace AA spectroscopy. The acids, designed for environmental and industrial applications, are accompanied by a certificate of analysis that lists lot number, expiry date, and actual concentration levels for over 60 elements.  

The SPECTRO GENESIS CCD ICP is factory calibrated and features the company's Intelligent Calibration Logic (ICAL) system, a software-based system that monitors and controls the state of the instrument independent from external influences. The unit requires no method development and features an Extended Markup Language (XML) LIMS interface. 

- The SPECTRO iQ is a polarized XRF analyzer for multielement analysis of solids, powders, and liquids. The analyzer features C-force optics, which reportedly deliver levels of sensitivity for elements such as Na, Mg, Al, Si, P, S, and Cl. Specific packages are available for the analysis of additives in oils, cement, slags, and refractories, as well as a "low S" version of the analyzer for the analysis of low levels of sulfur in fuels. 

- SPECTROMAXx spectrometers are designed for analyzing all common elements found in metals. Reportedly able to analyze nitrogen levels down to a level of 20 ppm, the spectrometers, which are available as either a bench-top or floor model, feature ICAL, which monitors system integrity and eliminates the need for recalibration samples. 

The PORTA-LIBS-2000 element analyzer integrates portable spectrometers from StellarNet and Kigre's 4-ns pulsed Nd:YAG NIR laser that delivers 6 mW to create a plasma. The portable instrument case is just 18 Ã 14 Ã 7 in. and operates via 12-V adapter or battery, with two high-resolution spectrometers. Depending upon detection requirements, as many as eight spectrometers can be attached via USB-2 computer interface. 

Leeman's ICP spectroscopy toolbox for use with the Prodigy ICP enables functions such as spectral additions and subtractions, which are particularly useful in forensic and quality control applications. Other features include a variety of spectral identifiers, which allow the user to perform tasks such as identifying unknown emission lines, superimposing the spectra from an element on an unknown spectrum, and determining the emission intensity of any emission line in the spectrum. 

- The Z-2000 series of atomic absorption spectrometers, announced in a partnership with Hitachi High Technologies, incorporates a dual detection system that allows the instrument to simultaneously monitor both total absorbance and background absorbance. This approach provides more accurate background correction for transient signals (such as those from graphite furnace) as well as a high degree of coincident noise rejection for flame-based measurements. The result is superior detection limits in both modes of operation when compared with conventional AC Zeeman techniques. 

- The Hydra AF Mercury Analyzer meets all hardware performance and QC requirements of EPA Method 245.7 (determination of mercury by simple atomic fluorescence). The instrument includes an atomic fluorescence-based detection system and calibration factor algorithms, as well as a built-in high capacity autosampler to ensure that it is able to meet the productivity requirements of today's labs. 

The ARL 9900 is a comprehensive X-ray analytical system that combines XRF and XRD technologies. This combination reportedly provides rapid and precise analysis of various samples and detection of as many as 83 elements (BâU) in concentrations ranging from parts-per-million to 100% and their corresponding specific phases. 

- The ARL QUANT'X is an X-ray that utilizes a Peltier cooled detector and Digital Pulse Processing technology, which reportedly improves throughput by ignoring scattered X-rays without the need for complicated polarizers. Typical applications include the non-destructive analysis of most elements, reportedly from a few parts-per-million levels in a variety of inorganic and organic sample types.  

Spectroscopy is proud to present its annual review of products displayed at our industry's premier trade show, the Pittsburgh Conference. The Spectroscopy editorial staff spent a good portion of the show investigating and collecting information on exhibitors' offerings, and a sampling of those instruments appear below, including a brief product description and the company's name and Web address. We have made every effort to provide as comprehensive a listing as possible, but as in years past, we cannot claim to have made a complete record of every product shown at the conference.

Spectroscopy-05-01-2005

Focus on Quality: Validation of Spectrometry Software

Theoretical and Experimental Investigation of the Electronic Spectra of Antitumor Compounds

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