the analytical chemist as expert witness

494 Vends in analyfical chemistry, vol. 7.5, no. 70, 7996

The analytical chemist as expert witness

Diana Simpson Thorpe-le-Soken, UK

In the current litigious age, expert witnesses are increasingly required for the courts. This article gives examples of both civil and criminal cases that have come into the author’s purview.

1. Confidence

On the occasions when I have been asked to pre- pare an article for publication or to give a lecture based on experience in consulting practice, it has always been necessary to point out that our work is confidential and we do not reveal even the names of our clients except in the most exceptional circum- stances - and then only with their permission. Because of this, although the essential details remain, all work described in this paper has been ‘scrambled’ to a certain extent to preserve such confidentiality.

Some references to analytical work, incidents and legal aspects of consulting practice have been made in earlier publications [ l-4 1. They are fields in which, if anything, both scientific and popular interest are still growing. Analysts have available a remarkable array of scientific procedures which can be of assistance in resolving intricate problems; the difficulties, in essence, are that while for a variety of reasons the work they do cannot always be conclu- sive, on occasions it has been accepted as if it were.

The references mentioned above include some general observations about giving evidence and two of them contain bibliographies with further reading. This article is intended to bring us to more recent times; for the most part it is anecdotal in nature and makes mention of both civil and criminal forensic cases.

Currently in the United Kingdom the Woolf Inquiry is in the process of proposing reforms on expert evidence. While it is not known yet what changes are to be made it is hoped that the professional societies will be able to safeguard the services to the public provided by their members.

In particular, the analytical chemist has much to offer to a court in the position of a wholly independent, unbiased expert, as a witness of the court assist- ing it in reaching decisions based on factual results.

2. Satisfactory evidence and maintaining standards

The references provide some earlier information about continued procedures in our practice and our approach to presenting scientific evidence, while examples cited elsewhere in this paper supplement this material. Usually, each case is different and is an opportunity to learn something new - maybe not only in the scientific sense, but also about human behaviour - but aside from this, and no matter how different a single case might seem at first, a certain underlying approach is always applicable.

Expressed in brief and simple terms, the objective is to tell the court exactly what we found or saw. Usually, in the first instance, the relevant report summarizes the situation as stated in the documents, followed by our description of the scene and of the exhibits or samples either as received at our premises or when we inspected them at the official establishment concerned.

Next comes a record of any preparative techniques applied to the samples, the methods of examination or analysis, a report of results obtained and conclusions as appropriate.

When information is derived from court papers or published sources, full references are included. Additionally, there may be photographs or draw- ings (or our comments about photographs and other items supplied to us). The objective is to be comprehensive, open and clear (not, of course, repetitive, or offering hearsay), so that if it should wish to do so the court may examine any aspect of the work. Similarly, the report should put other experts in a position to be able to assess the standard of the work done. All records (such as laboratory notebooks) are kept carefully and are available to be produced if required.

It might be that on occasion the actual circum- stances dictate some changes from procedures that

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trends in analytical chemistry, vol. 75, no. 10, 1996 495

would be desirable (perhaps, say, because the samples available are very small), but when this has been so we believe it should be stated clearly, with the reasons. On other occasions, particularly when the samples have been exhausted beforehand, or were perishable, all that is possible is to review the report or reports by experts for the prosecution in criminal cases, or for plaintiff or defendant in civil cases.

It is my impression that there might be merit in the recent proposal to improve training at school in how words should be used, and I find often when reviewing papers and the scientific literature that even well-qualified scientists can write with undue obscurity. However, irrespective of whether the general standards of expression are rising or falling, it is indisputable that for a court the most effective scientific report will be the one that can be understood readily. In other words, time and care are needed when preparing the report, as well as during the investigation proper.

In short, it is of particular importance that the independent expert should be experienced, well- qualified and conscious at all times of the importance of setting high standards, and of keeping to them.

3. ‘Chutzpah’ is not enough

On 28 May 1996, the legal pages of The Times newspaper included an article entitled Who Checks Forensics ?, in which quotations were given of remarks by a member of a consultancy practice, the forensic scientists of which all were formerly members of Metropolitan Police and/or Home Office establishments. According to the quotations there were no checks, ‘anyone with a white coat’ could set himself up, and there were ‘no minimum standards, no minimum qualifications and no set procedures.’ The only thing necessary was ‘a bit of chutzpah’ on the part of the individual.

It is true that over a period of time an attitude of mind has developed in which a defence might just accept whatever the man or woman from the official laboratory might say; obviously it has happened, and obviously it is a danger. Sad though it might be to feel obliged to write it, perhaps it is necessary to point out that science is no one’s monopoly.

If the remarks quoted were true, why (in contrast with independent practitioners) have there been what can only be described as ‘scandals’ on the government side, and might they be merely the tip of an iceberg’?

Speaking for myself after being instructed by defence in criminal cases, and by both sides in civil suits, I do not believe that ‘a bit of chutzpah’ is quite enough to sustain an independent practi- tioner. The reality, I think, is that the independent forensic scientist must be more careful, more objective, in fact ylzore scientific than the official. He or she is often at the disadvantage of being called on late, even after samples have been destroyed, may be required to work at the government laboratory or in a local police station when the authorities are reluctant to release samples for independent examination, and sometimes even after a hearing has begun.

In magistrates’ courts especially I find the incli- nation often is just to accept the official evidence (one finds, for example, that one is questioned closely as to whether one used the same techniques as the official expert, the implication being that he or she sets the standard), and at any level in the hierarchy it is of the utmost importance for the out- sider such as myself to establish his or her credibil- ity as a witness of‘the court.

There is a great body of experience and know- ledge which would and ought to be at the service of justice; it would be wrong morally and unwise from the legal point of view if scientific evidence were to be available only from approved officials.

I might mention in this connection that independent legal references are required before an expert

trends in analytical chemistry, vol. 15, no. 70, 7996

can be included in the Law Society’s list of expert witnesses (and for other lists of comparable stand- ing), and that there are still independent professional institutes awarding qualifications for merit and experience, together with and proof of continued professional development. To give one example, The Royal Society of Chemistry publishes Indicative Registers, including those for certifi- cated analytical chemists, health and safety specia- lists and professional water chemists, for all of whom continued professional development is a condition of inclusion.

More to the point, the courts and the legal profes- sion have ample means of indicating dissatisfaction with any person attempting to practice on the basis suggested (of ‘chutzpah’). The professional institutes have disciplinary procedures, which are enforced if need be. What is needed desperately, I believe, is not regimentation as implied by The Times article, but fresh air.

It would be neither right nor proper of me to comment with any particularity on cases that have been reported in the media (and some still may be sub j&ice). Nor is it for me to comment adversely on the work of any particular forensic scientist employed by the prosecution. I must add that when I have visited any laboratory in order to carry out analytical work (not always easy in a different environment) and met police and prose- cuting scientists I have never found anything other than courtesy extended to me.

In general when I read in the press about what appears to be an elementary point of sampling or analysis having been overlooked, my immediate reaction is to become incensed at the apparent lack of care, but then I do not know all the facts. Press reports of this kind reflect badly on all scientists. As it is, judges often have mixed views of ‘experts’ and (as an illustration) I recall one case with which I was involved when the prosecution scientist replied quite properly that a certain matter was outside his field and the judge called an adjournment until the prosecution found another person who was prepared to answer.

It is very important not merely to have a white coat but to offer evidence only on subjects in which one is qualified and has a great deal of experience. Otherwise, one risks being tied in knots. The first and second requests to be made in an examination are for one’s qualifications and a summary of experience in the type of work on which evidence is to be given. Close questioning in relation to experience is usual.

4. Selected examples of expert witness work

In recent years, understandably enough, the defence in criminal cases has been showing more interest in engaging experts - a trend which should help in reducing any scientific problems over prosecution data. Naturally, as individuals, some solic- itors will be more at ease with a report by an expert than are others; the capacities to accept and to make proper use of the information differ. There is little the expert can do about this (other than, as usual, by trying to explain everything carefully and clearly), but he or she is not likely to respond well to the occasional briefing beginning in terms such as: ‘What I want from you is...’ (it might have to be stated emphatically that what the report says will be what is found).

The examples that follow are based on my own cases, mainly because with others less complete details necessarily would be available. It was mentioned before that it still is not unusual to be tele- phoned while a case is being heard. Whether this happens because of pressure of other work in the lawyers’ offices I do not know, but most analysts will appreciate that a definite period of time may be needed - as when samples have to be conditioned or extracted over a period - so some questions simply cannot be answered ‘off the cuff.’

A scientific problem can emerge in the course of a hearing but I doubt whether this was the explana- tion when I was asked in a telephone call from the Old Bailey - ‘I have a white powder here - what could it be?’

The first example 1 will outline concerned an accusation by a manufacturer of colorants in the cosmetics trade against a person who had left his

trends in analytical chemistry, vol. 7.5, no. 70, 7996 497

employment and was alleged to have taken with him the former employer’s formulations in order to start a business of his own. My involvement arose when I was consulted by the defendant’s solicitor in order to investigate the allegations, as the defendant was in receipt of a court order preventing him from furthering his new business, and wished to appeal against it.

I was presented with a large number of colorants, representing the formulations of both the defendant and the plaintiff, for investigation and comparison.

The techniques I employed included comparison microscopy, thin-layer chromatography and ex- traction procedures. The results obtained indicated clearly that the formulations were dissimilar. In some instances it could be seen by the naked eye that the comparable colours of so-called ‘identical’ formulations were not the same. Thin-layer chromatography also confirmed the presence of different components. When the appeal was to be heard in the High Court I took along the thin-layer chromatographic plates together with large microscope slides containing for comparison streaks of each formulation. My cause was helped considerably by the fact that the plaintiff’s submissions included no analyses, merely a perusal of the stated formulations of the plaintiff and the defendant. The plaintiff settled on the third day.

In the second example, a medium-sized com- pany in the south of England had been accused of depositing harmful waste on a marsh area that it owned and part of which had been employed as a wharf for a long time. It was summoned to appear in a Magistrates’ Court six weeks later for a large number of alleged offences, all of which were essentially the same (that is, similar offences at differing dates and times).

I visited the area concerned, obtained brief details of its history and local maps, took photographs and samples of the ‘harmful waste,’ which at first sight appeared to be general dust and dirt. On the way back to the practice I also took samples of general road dust and dirt, some from a lay-by a few miles from the site. At the laboratory the samples were separated carefully by eye and with the help of lenses and the different components identified by means of techniques including infrared and atomic absorption spectrometry. A report was prepared describing briefly the site, the operations of the defendant, the results of analysis and my conclusions. The findings were a little puzzling inasmuch as the samples from the marsh area were similar in many respects to the road samples taken, except

that the former contained ceramic fragments. No obviously hazardous components were found. The client, through his solicitor, informed us that he had obtained the waste from a ceramics factory that had ceased trading, which waste was said to contain tiny fragments of pottery and calcium salts. The client had used the waste to provide a level surface on the marsh with a view to preventing accidents to vehicles and drivers.

At the hearing I gave my evidence and pointed out the similarities between the various components found in the samples. The magistrates were offered the opportunity to visit the site to obtain a first-hand impression, and did so. During the inspection one of the magistrates was heard to comment that some parts of where they were walking really needed more of the filling of the surface than had actually been applied! On returning to the Court the magistrates found for the defendant.

,,. -, ‘,

For a third example I refer to samples received under the Road Traffic Act for determination of ethyl alcohol in blood or urine-a more usual aspect of the work, which is done using a well-established gas chromatographic procedure.

A somewhat more problematic issue in connection with some of these samples is that of the retrospective alcohol calculation. In such calculations so many assumptions have to be made that it is a moot point as to how much credence should be placed on them. My own view is that results of this nature can only be very approximate but, as they are accepted from the prosecution, they must also be accepted from the defence.

Retrospective calculations are based on the sur- mise that the rate of elimination of alcohol from the blood would vary according to the individual between about 10 and 30 mg per 100 ml per hour; it is generally accepted practice to take a figure of

498 fiends in analytical chemistry, vol. 15, no. 70, 7996

15 mg per 100 ml per hour. In addition to this calculation a factor known as the ‘Widmark factor’ is used. This is based on a factor, body weight and the weight of alcohol imbibed. The result is particularly difficult to obtain with any accuracy when drinks are said to have been ‘spiked.’ One instance was especially difficult when one of the witnesses, who agreed that he had added spirit to some stout was asked in court how much he had added. He replied that he had added ‘one glug,’ and later on a ‘glug glug.’ I was asked during my evidence how much I thought a ‘glug’ was!

I had taken a measuring cylinder with me and using it in conjunction with the court’s water jug fortunately was able to improvise a reply. Fortu- nately also I had a pocket calculator and was able to work out quickly the possible effects of drinks of different alcoholic strength taken at different times.

Another joy for an expert witness is giving evidence at a tribunal. Some time ago a request was received to take samples at the premises of a boat- builder, who had been given planning permission which subsequently was withdrawn. Apparently a playschool in a local residential area was said to be ‘uninhabitable’ because of the smell from the factory. On investigating it was found that the odour was styrene and monitoring of the unit was performed. Samples were taken from atmosphere on to activated carbon, desorbed and analysed using gas chromatography. The level of styrene was very low and well within the approved occupational exposure standards. Unfortunately, the odour of styrene is detectable by nose at a very low level and the proprietor of the playschool took the matter to a tribunal.

One difference between a civil or criminal Court of Law and a Tribunal is that the latter often has a large number of vociferous attendees. In this instance they were local residents and mothers concerned for their children’s health, and not a few people from some distance away. The boat-builder had attempted to disguise the smell of styrene by the use of a counter-odorant, the main property of which appeared to be to cause interference with the analytical method employed.

It is difficult to point out that the levels found were extremely low when styrene may be detected at a very few parts per million by nose. After, among other things, an examination on its possible and alleged effects, it was recommended that the boat-builder be allowed to continue his business provided he fitted a filter to collect any odour, and this was agreed. Unfortunately, following the

fitting of the filter (which could deal with the styrene admirably) the relevant inspector found on his next visit that it had not been switched on.

5. Not coming to court

There are, of course, occasions when, although one is engaged as an expert witness, the case does not reach court for a variety of reasons. In other examples it might not be necessary or even desired by the solicitor concerned for me to attend - perhaps because my analysis has shown his client to be guilty of the offence alleged and the plea has had to be changed from ‘not guilty’ to ‘guilty.’ In civil disputes especially it often is possible to arrive at acceptable settlements without formal hearings, which sometimes are lengthy and expensive.

An occasion when 1 was pleased not to have to attend was after the visit of a wife in tears because she suspected her husband of a liaison with another woman. Especially when a client appears with no warning it is difficult to refuse such work (in this instance the lady had been informed by a kind solicitor that she would receive a sympathetic hearing from me ‘because I too was a woman’). She had brought her husband’s shirt so that I could see the blonde hairs on it. Fortunately I was able later, after a certain amount of microscopy, to report that they were dog hairs. The client, now all smiles, said: ‘Oh, they must be from our golden retriever.’

Sometimes it is not considered necessary to have analytical work done and I may be required merely to comment on documents received, perhaps because of the cost of analytical investigation, because no samples are available, or when a considerable time has elapsed since the incident alleged and the commencement of the case.

One such example (but where I did attend) was the proprietor of a very small restaurant in a remote place who had used a machine to wash vegetables and allowed the washings, including any soil, to pass into a ditch or small stream just beyond the bottom of his garden. He was prosecuted because of alleged ‘pollution’ of the stream. It appeared from reading the documents that a local government official had taken one sample ‘upstream’ and one ‘downstream’ and based the case on analyses that had been performed by a laboratory in the part of the country where the alleged pollution had occurred. He brought the samples to court, one of which was described as ‘crystal clear’ the other ‘looking as though it was low in oxygen.’ As the

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‘crystal clear’ sample had been recorded as having a not insignificant amount of suspended solids pres- ent, and in answer to a hissed request in my ear from the solicitor as to what questions he should ask, I suggested that he ask the person who had prepared part of the analytical report and who had brought his laboratory notebook with him what was the appearance of the samples as received. The answer: ‘Oh, we don’t record the appearance.’ There is little one can do in the face of such a reply.

In general in criminal cases, I have found the officials, including the police, to be friendly and helpful but it is not always easy for an expert engaged by the defence to obtain samples for analysis. Often he or she is at the disadvantage of being called on late, sometimes even after the samples have been destroyed by the prosecution, and may be required to work at the laboratory used by the prosecution (or, when the authorities are reluctant to release samples for independent examination, even at a police station). Such a system does not apply under Scottish law, where both defence and prosecution forensic scientists are able to take and examine samples.

Some years ago I was asked to perform analyses for a solicitor with clients who had been arrested and charged with attempted safe-breaking. The case against them was considered so clear and posi- tive that the police refused to allow the evidence to be returned to the Home Office laboratory for any subsequent work. Nevertheless, in view of his clients’ vehement assertions that they were not guilty, the solicitor considered that he should insist on further work and he asked me to attend at the police station (a considerable distance away) to do whatever examination was considered necessary.

As a safe had been mentioned, a colleague accompanied me should heavy lifting by two persons be needed, and we presented ourselves at the appropriate place. We were received courteously although with a certain amount of mystification as there seemed little doubt about the guilt of the accused. Two persons indeed were needed to move the safe and it was necessary also to examine the tools which had been found in the possession of the accused. These comprised three small screw- drivers (unpainted), a hammer (unpainted), a large chisel (painted partially with black paint), a tyre lever (unpainted), various cloths, etc.

Although it was necessary I had taken with us reluctantly one of our expensive microscopes

(reluctantly because they do not travel well) and was able to compare scratch marks on the tools with those on the safe. Some scratch marks could have appeared similar but on the whole I found them inconclusive. The black paint on the chisel blade appeared similar to that on the safe and I was allowed to take away scrapings from each. Nothing of significance appeared to be obvious on the other tools. The safe was very heavy and the small screw- drivers seemed unsuitable for forcing it open.

Subsequently the paint from the chisel and from the safe were analysed and compared, using infrared and atomic absorption spectrometry and separation techniques. I found the two types of paint to be fairly similar with regard to polymeric components, but the fillers used in the paints were not the same. I prepared and sent the relevant report to the solicitor, and prepared to attend court in the usual way. However, before the commencement of the trial the prosecution informed the court that it would not be putting forward any further evidence and the case was dismissed.

6. The female analytical chemist as expert witness

Women have been employed by the Forensic Science Service for many years but sometimes it still seems to come as a surprise when a woman appears either as an expert called by the defence or in certain of the civil courts. A couple of examples of dialogues experienced:

( 1) Judge: ‘I have Dr. Simpson’s report here. He says that...’

1 st Barrister: ‘My Lord, Dr. Simpson is a lady.’ 2nd Barrister: ‘My Lord, it is Dr. Mrs. Simpson.’ Judge: ‘What does he say though?’ (2) Barrister: ‘Dr. Simpson, please would you

tell the court your qualifications?’ D. Simpson: ‘MPhil, PhD,...’ Judge (interrupting): ‘Yes, thank you, we all

know that you are a clever woman.’ To be fair, these are the sort of incidents that stay

in the memory, and it is by no means always like this. From what one has seen of the courts in the capacity of an expert, a generous supply of patience is essential for judges and the professional lawyers. Although the woman expert witness cannot help being female, the analytical chemist can be alert to their need for clarity and objectivity.

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References

[ l] D. Simpson, Anal. Proc., 21 (1984) 385. [ 21 D. Simpson and W.G. Simpson, An Introduction

to Applications of Light Microscopy in Analysis, Royal Society of Chemistry, London, 1988, p. 164.

[ 31 D. Simpson and W.G. Simpson (Editors), The COSHH Regulations: A Practical Guide, Royal Society of Chemistry, Cambridge, 199 1, p. 1.

[ 41 D. Simpson, Chromatography, 39 (Oct./Nov.) (1995) 9.

Dr. Diana Simpson is at Analysis For Industry, Factories 213, Bosworth House, High Street, Thorpe-le-Soken, Essex CO16 OEA, UK. She has over 30 years experience as an industrial analytical chemist in various fields covering food, water, plastics, pharmaceuticals and occupational hygiene. The practice of Analysis For Industry was established in 1975 with Dr. Simpson and her husband as Principal Consultants and she has been involved in forensic science and expert witness work since that time.

Using dynamic data exchange- to exchange information between Visual Basic and Matlab

Application to a diode array spectrophotometer

Eduardo 0. de Cerqueira, Ronei J. Poppi* Campinas, Brazil

Photodiode array spectrometers are increasingly being coupled to flow analysis and separation techniques. Computer programs are needed to control the data acquisition from each photodiode and to handle the data. The Microsoft Visual Basic programming language is used along with a DLL library and dynamic data exchange (DDE) to allow communication with the MATLAB com- putational environment.

1. Introduction

Photodiode array spectrophotometers are increasingly being used in analytical chemistry because they contain no moving parts and a full spectrum can be obtained in a few milliseconds [ 11, making possible their application with techniques such as high performance liquid chromatography [ 21 and flow injection analysis [ 3 1. Com- mercial instruments have been used frequently although home-made prototypes are also described in the literature [ 41.

*Corresponding author.

0165-9936/96/$15.00 PUSO165-9936(96)00052-O

In our work, a photodiode array spectrophotometer was mounted for use in flow injection analysis systems, using a monochromator in conjunction with a silicon photodiode array detector placed on the focal plane. For this implementation it was necessary to develop a computer program to control the data acquisition for each photodiode and to handle the data from the FIA manifold.

The computer program was developed in Visual Basic version 3.0, a programming language for the Windows environment that has been widely accepted by chemists [ 5,6]. Actually, Visual Basic does not support intrinsic functions capable of writing a byte into a specific microcomputer out- put device address, or of reading a byte from a microcomputer input device address. These functions are necessary to control the data acquisition, and to overcome this serious Visual Basic limita- tion a DLL library called INPOUT.DLL written in Assembler was employed. This library is available as public domain software in the Internet sites that offer Windows applications (for example, the Indi- ana University Windows repository site: ftp.cica. indiana.edu).

An important characteristic of Visual Basic is related to the multi-tasking operating environment of Windows. If Visual Basic and another application are running at the same time, automatic data exchange between programs is possible using dynamic data exchange (DDE). By using this fea-

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the analytical chemist as expert witness

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